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Middleware API

This chapter describes the Middleware API for SIP SIMPLE client SDK that can be used for developing a user interface (e.g. Graphical User Interface). The Middleware provides a non-blocking API that communicates with the user interface asynchronously by using Notifications. For its configuration, the Middleware uses the Configuration API.

SIPApplication

Implemented in sipsimple/application.py

Implements a high-level application responsable for starting and stopping various sub-systems required to implement a fully featured SIP User Agent application. The SIPApplication class is a Singleton and can be instantiated from any part of the code, obtaining a reference to the same object. The SIPApplication takes care of initializing the following components:

the twisted thread
the configuration system, via the ConfigurationManager
the core Engine using the settings in the configuration
the AccountManager, using the accounts in the configuration
the SessionManager, in order to handle incoming sessions
two AudioBridges, using the settings in the configuration

The attributes in this class can be set and accessed on both this class and its subclasses, as they are implemented using descriptors which keep single value for each attribute, irrespective of the class from which that attribute is set/accessed. Usually, all attributes should be considered read-only.

methods

__init__(self): Instantiates a new SIPApplication.

start(self, config_backend): Starts the SIPApplication which initializes all the components in the correct order. The config_backend is used to start the ConfigurationManager. If any error occurs with loading the configuration, the exception raised by the ConfigurationManager is propagated by this method and SIPApplication can be started again. After this, any fatal errors will result in the SIPApplication being stopped and unusable, which means the whole application will need to stop. This method returns as soon as the twisted thread has been started, which means the application must wait for the SIPApplicationDidStart notification in order to know that the application started.

stop(self): Stop all the components started by the SIPApplication. This method returns immediately, but a SIPApplicationDidEnd notification is sent when all the components have been stopped.

attributes

running: True if the SIPApplication is running (it has been started and it has not been told to stop), False otherwise.

alert_audio_mixer: The AudioMixer object created on the alert audio device as defined by the configuration (by SIPSimpleSettings.audio.alert_device).

alert_audio_bridge: An AudioBridge where IAudioPort objects can be added to playback sound to the alert device.

alert_audio_device: An AudioDevice which corresponds to the alert device as defined by the configuration. This will always be part of the alert_audio_bridge.

voice_audio_mixer: The AudioMixer object created on the voice audio device as defined by the configuration (by SIPSimpleSettings.audio.input_device and SIPSimpleSettings.audio.output_device).

voice_audio_bridge: An AudioBridge where IAudioPort objects can be added to playback sound to the output device or record sound from the input device.

voice_audio_device: An AudioDevice which corresponds to the voice device as defined by the configuration. This will always be part of the voice_audio_bridge.

notifications

SIPApplicationWillStart: This notification is sent just after the configuration has been loaded and the twisted thread started, but before any other components have been initialized.
timestamp:
A datetime.datetime object indicating when the notification was sent.

SIPApplicationDidStart: This notification is sent when all the components have been initialized. Note: it doesn't mean that all components have succeeded, for example, the account might not have registered by this time, but the registration process will have started.
timestamp:
A datetime.datetime object indicating when the notification was sent.

SIPApplicationWillEnd: This notification is sent as soon as the stop() method has been called.
timestamp:
A datetime.datetime object indicating when the notification was sent.

SIPApplicationDidEnd: This notification is sent when all the components have been stopped. All components have been given reasonable time to shutdown gracefully, such as the account unregistering. However, because of factors outside the control of the middleware, such as network problems, some components might not have actually shutdown gracefully; this is needed because otherwise the SIPApplication could hang indefinitely (for example because the system is no longer connected to a network and it cannot be determined when it will be again).
timestamp:
A datetime.datetime object indicating when the notification was sent.

SIPApplicationFailedToStartTLS: This notification is sent when a problem arises with initializing the TLS transport. In this case, the Engine will be started without TLS support and this notification contains the error which identifies the cause for not being able to start the TLS transport.
timestamp:
A datetime.datetime object indicating when the notification was sent.
error:
The exception raised by the Engine which identifies the cause for not being able to start the TLS transport.

SIP Sessions

SIP sessions are supported by the sipsimple.session.Session class and independent stream classes, which need to implement the sipsimple.streams.IMediaStream interface. The Session class takes care of the signalling, while the streams offer the actual media support which is negotiated by the Session. The streams which are implemented in the SIP SIMPLE middleware are provided in modules within the sipsimple.streams package, but they are accessible for import directly from sipsimple.streams. Currently, the middleware implements two types of streams, one for RTP data, with a concrete implementation in the AudioStream class, and one for MSRP sessions, with concrete implementations in the ChatStream, FileTransferStream and DesktopSharingStream classes. However, the application can provide its own stream implementation, provided they respect the IMediaStream interface.

The sipsimple.streams module also provides a mechanism for automatically registering media streams in order for them to be used for incoming sessions. This is explained in more detail in MediaStreamRegistry.

SessionManager

Implemented in sipsimple/session.py

The sipsimple.session.SessionManager class is a singleton, which acts as the central aggregation point for sessions within the middleware. Although it is mainly used internally, the application can use it to query information about all active sessions. The SessionManager is implemented as a singleton, meaning that only one instance of this class exists within the middleware. The SessionManager is started by the SIPApplication and takes care of handling incoming sessions and closing all sessions when SIPApplication is stopped.

attributes

sessions: A property providing a copy of the list of all active Sesssion objects within the application, meaning any Session object that exists globally within the application and is not in the NULL or TERMINATED state.

methods

__init__(self): Instantiate a new SessionManager object.

start(self): Start the SessionManager in order to be able to handle incoming sessions. This method is called automatically when SIPApplication is started. The application should not call this method directly.

stop(self): End all connected sessions. This method is called automatically when SIPApplication is stopped. The application should not call this method directly.

Session

Implemented in sipsimple/session.py

A sipsimple.session.Session object represents a complete SIP session between the local and a remote endpoints. Both incoming and outgoing sessions are represented by this class.

A Session instance is a stateful object, meaning that it has a state attribute and that the lifetime of the session traverses different states, from session creation to termination. State changes are triggered by methods called on the object by the application or by received network events. These states and their transitions are represented in the following diagram:

Although these states are crucial to the correct operation of the Session object, an application using this object does not need to keep track of these states, as a set of notifications is also emitted, which provide all the necessary information to the application.

The Session is completely independent of the streams it contains, which need to be implementations of the sipsimple.streams.IMediaStream interface. This interface provides the API by which the Session communicates with the streams. This API should not be used by the application, unless it also provides stream implementations or a SIP INVITE session implementation.

methods

__init__(self, account): Creates a new Session object in the None state.
account:
The local account to be associated with this Session.

connect(self, to_header, routes, streams): Will set up the Session as outbound and propose the new session to the specified remote party and move the state machine to the outgoing state. Before contacting the remote party, a SIPSessionNewOutgoing notification will be emitted. If there is a failure or the remote party rejected the offer, a SIPSessionDidFail notification will be sent. Any time a ringing indication is received from the remote party, a SIPSessionGotRingIndication notification is sent. If the remote party accepted the session, a SIPSessionWillStart notification will be sent, followed by a SIPSessionDidStart notification when the session is actually established. This method may only be called while in the None state.
to_header:
A sipsimple.core.ToHeader object representing the remote identity to initiate the session to.
routes:
An iterable of sipsimple.util.Route objects, specifying the IP, port and transport to the outbound proxy. These routes will be tried in order, until one of them succeeds.
streams:
A list of stream objects which will be offered to the remote endpoint.

send_ring_indication(self): Sends a 180 provisional response in the case of an incoming session.

accept(self, streams): Calling this methods will accept an incoming session and move the state machine to the accepting state. When there is a new incoming session, a SIPSessionNewIncoming notification is sent, after which the application can call this method on the sender of the notification. After this method is called, SIPSessionWillStart followed by SIPSessionDidStart will be emitted, or SIPSessionDidFail on an error. This method may only be called while in the incoming state.
streams:
A list of streams which needs to be a subset of the proposed streams which indicates which streams are to be accepted. All the other proposed streams will be rejected.

reject(self, code=603, reason=None): Reject an incoming session and move it to the terminating state, which eventually leads to the terminated state. Calling this method will cause the Session object to emit a SIPSessionDidFail notification once the session has been rejected. This method may only be called while in the incoming state.
code:
An integer which represents the SIP status code in the response which is to be sent. Usually, this is either 486 (Busy) or 603 (Decline/Busy Everywhere).
reason:
The string which is to be sent as the SIP status reason in the response, or None if PJSIP's default reason for the specified code is to be sent.

accept_proposal(self, streams): When the remote party proposes to add some new streams, signaled by the SIPSessionGotProposal notification, the application can use this method to accept the stream(s) being proposed. After calling this method a SIPSessionGotAcceptProposal notification is sent, unless an error occurs while setting up the new stream, in which case a SIPSessionHadProposalFailure notification is sent and a rejection is sent to the remote party. As with any action which causes the streams in the session to change, a SIPSessionDidRenegotiateStreams notification is also sent. This method may only be called while in the received_proposal state.
streams:
A list of streams which needs to be a subset of the proposed streams which indicates which streams are to be accepted. All the other proposed streams will be rejected.

reject_proposal(self, code=488, reason=None): When the remote party proposes new streams that the application does not want to accept, this method can be used to reject the proposal, after which a SIPSessionGotRejectProposal or SIPSessionHadProposalFailure notification is sent. This method may only be called while in the received_proposal state.
code:
An integer which represents the SIP status code in the response which is to be sent. Usually, this is 488 (Not Acceptable Here).
reason:
The string which is to be sent as the SIP status reason in the response, or None if PJSIP's default reason for the specified code is to be sent.

add_stream(self, stream): Proposes a new stream to the remote party. Calling this method will cause a SIPSessionGotProposal notification to be emitted. After this, the state machine will move into the sending_proposal state until either a SIPSessionGotAcceptProposal, SIPSessionGotRejectProposal or SIPSessionHadProposalFailure notification is sent, informing the application if the remote party accepted the proposal. As with any action which causes the streams in the session to change, a SIPSessionDidRenegotiateStreams notification is also sent. This method may only be called while in the connected state.

remove_stream(self, stream): Stop the stream and remove it from the session, informing the remote party of this. Although technically this is also done via an SDP negotiation which may fail, the stream will always get remove (if the remote party refuses the re-INVITE, the result will be that the remote party will have a different view of the active streams than the local party). This method may only be called while in the connected state.

cancel_proposal(self): This method cancels a proposal of adding a stream to the session by sending a CANCEL request. A SIPSessionGotRejectProposal notification will be sent with code 487.

hold(self): Put the streams of the session which support the notion of hold on hold. This will cause a SIPSessionDidChangeHoldState notification to be sent. This method may be called in any state and will send the re-INVITE as soon as it is possible.

unhold(self): Take the streams of the session which support the notion of hold out of hold. This will cause a SIPSessionDidChangeHoldState notification to be sent. This method may be called in any state and will send teh re-INVITE as soon as it is possible.

end(self): This method may be called any time after the Session has started in order to terminate the session by sending a BYE request. Right before termination a SIPSessionWillEnd notification is sent, after termination SIPSessionDidEnd is sent.

attributes

state: The state the object is currently in, being one of the states from the diagram above.

account: The sipsimple.account.Account or sipsimple.account.BonjourAccount object that the Session is associated with. On an outbound session, this is the account the application specified on object instantiation.

direction: A string indicating the direction of the initial negotiation of the session. This can be either None, "incoming" or "outgoing".

transport: A string representing the transport this Session is using: "udp", "tcp" or "tls".

start_time: The time the session started as a datetime.datetime object, or None if the session was not yet started.

stop_time: The time the session stopped as a datetime.datetime object, or None if the session has not yet terminated.

on_hold: Boolean indicating whether the session was put on hold, either by the local or the remote party.

remote_user_agent: A string indicating the remote user agent, if it provided one. Initially this will be None, it will be set as soon as this information is received from the remote party (which may be never).

local_identity: The sipsimple.core.FrozenFromHeader or sipsimple.core.FrozenToHeader identifying the local party, if the session is active, None otherwise.

remote_identity: The sipsimple.core.FrozenFromHeader or sipsimple.core.FrozenToHeader identifying the remote party, if the session is active, None otherwise.

streams: A list of the currently active streams in the Session.

proposed_streams: A list of the currently proposed streams in the Session, or None if there is no proposal in progress.

notifications

SIPSessionNewIncoming: Will be sent when a new incoming Session is received. The application should listen for this notification to get informed of incoming sessions.
timestamp:
A datetime.datetime object indicating when the notification was sent.
streams:
A list of streams that were proposed by the remote party.

SIPSessionNewOutgoing: Will be sent when the applcation requests a new outgoing Session.
timestamp:
A datetime.datetime object indicating when the notification was sent.
streams:
A list of streams that were proposed to the remote party.

SIPSessionGotRingIndication: Will be sent when an outgoing Session receives an indication that a remote device is ringing.
timestamp:
A datetime.datetime object indicating when the notification was sent.

SIPSessionGotProvisionalResponse: Will be sent whenever the Session receives a provisional response as a result of sending a (re-)INVITE.
timestamp:
A datetime.datetime object indicating when the notification was sent.
code:
The SIP status code received.
reason:
The SIP status reason received.

SIPSessionWillStart: Will be sent just before a Session completes negotiation. In terms of SIP, this is sent after the final response to the INVITE, but before the ACK.
timestamp:
A datetime.datetime object indicating when the notification was sent.

SIPSessionDidStart: Will be sent when a Session completes negotiation and all the streams have started. In terms of SIP this is sent after the ACK was sent or received.
timestamp:
A datetime.datetime object indicating when the notification was sent.
streams:
The list of streams which now form the active streams of the Session.

SIPSessionDidFail: This notification is sent whenever the session fails before it starts. The failure reason is included in the data attributes. This notification is never followed by SIPSessionDidEnd.
timestamp:
A datetime.datetime object indicating when the notification was sent.
originator:
A string indicating the originator of the Session. This will either be "local" or "remote".
code:
The SIP error code of the failure.
reason:
A SIP status reason.
failure_reason:
A string which represents the reason for the failure, such as "user_request", "missing ACK", "SIP core error...".

SIPSessionWillEnd: Will be sent just before terminating a Session.
timestamp:
A datetime.datetime object indicating when the notification was sent.

SIPSessionDidEnd: Will be sent always when a Session ends as a result of remote or local session termination.
timestamp:
A datetime.datetime object indicating when the notification was sent.
originator:
A string indicating who originated the termination. This will either be "local" or "remote".
end_reason:
A string representing the termination reason, such as "user_request", "SIP core error...".

SIPSessionDidChangeHoldState: Will be sent when the session got put on hold or removed from hold, either by the local or the remote party.
timestamp:
A datetime.datetime object indicating when the notification was sent.
originator:
A string indicating who originated the hold request, and consequently in which direction the session got put on hold.
on_hold:
True if there is at least one stream which is on hold and False otherwise.
partial:
True if there is at least one stream which is on hold and one stream which supports hold but is not on hold and False otherwise.

SIPSessionGotProposal: Will be sent when either the local or the remote party proposes to add streams to the session.
timestamp:
A datetime.datetime object indicating when the notification was sent.
originator:
The party that initiated the stream proposal, can be either "local" or "remote".
streams:
A list of streams that were proposed.

SIPSessionGotRejectProposal: Will be sent when either the local or the remote party rejects a proposal to have streams added to the session.
timestamp:
A datetime.datetime object indicating when the notification was sent.
originator:
The party that initiated the stream proposal, can be either "local" or "remote".
code:
The code with which the proposal was rejected.
reason:
The reason for rejecting the stream proposal.
streams:
The list of streams which were rejected.

SIPSessionGotAcceptProposal: Will be sent when either the local or the remote party accepts a proposal to have stream( added to the session.
timestamp:
A datetime.datetime object indicating when the notification was sent.
originator:
The party that initiated the stream proposal, can be either "local" or "remote".
streams:
The list of streams which were accepted.
proposed_streams:
The list of streams which were originally proposed.

SIPSessionHadProposalFailure: Will be sent when a re-INVITE fails because of an internal reason (such as a stream not being able to start).
timestamp:
A datetime.datetime object indicating when the notification was sent.
failure_reason:
The error which caused the proposal to fail.
streams:
The streams which were part of this proposal.

SIPSessionDidRenegotiateStreams: Will be sent when a media stream is either activated or deactivated. An application should listen to this notification in order to know when a media stream can be used.
timestamp:
A datetime.datetime object indicating when the notification was sent.
action:
A string which is either "add" or "remove" which specifies what happened to the streams the notificaton referes to
streams:
A list with the streams which were added or removed.

SIPSessionDidProcessTransaction: Will be sent whenever a SIP transaction is complete in order to provide low-level details of the progress of the INVITE dialog.
timestamp:
A datetime.datetime object indicating when the notification was sent.
originator:
The initiator of the transaction, "local" or "remote".
method:
The method of the request.
code:
The SIP status code of the response.
reason:
The SIP status reason of the response.
ack_received:
This attribute is only present for INVITE transactions and has one of the values True, False or "unknown". The last value may occur then PJSIP does not let us know whether the ACK was received or not.

As an example for how to use the Session object, the following provides a basic Python program that initiates an outgoing SIP session request see Minimalist Session Example code.

IMediaStream

Implemented in sipsimple/streams/__init__.py

This interface describes the API which the Session uses to communicate with the streams. All streams used by the Session must respect this interface.

methods

__init__(self, account): Initializes the generic stream instance.

new_from_sdp(cls, account, remote_sdp, stream_index): A classmethod which returns an instance of this stream implementation if the sdp is accepted by the stream or None otherwise.
account:
The sipsimple.account.Account or sipsimple.account.BonjourAccount object the session which this stream would be part of is associated with.
remote_sdp:
The FrozenSDPSession which was received by the remote offer.
stream_index:
An integer representing the index within the list of media streams within the whole SDP which this stream would be instantiated for.

get_local_media(self, for_offer): Return an SDPMediaStream which represents an offer for using this stream if for_offer is True and a response to an SDP proposal otherwise.
for_offer:
True if the SDPMediaStream will be used for an SDP proposal and False if for a response.

initialize(self, session, direction): Initializes the stream. This method will get called as soon as the stream is known to be at least offered as part of the Session. If initialization goes fine, the stream must send a MediaStreamDidInitialize notification or a MediaStreamDidFail notification otherwise.
session:
The Session object this stream will be part of.
direction:
"incoming" if the stream was created because of a received proposal and "outgoing" if a proposal was sent. Note that this need not be the same as the initial direction of the Session since streams can be proposed in either way using re-INVITEs.

start(self, local_sdp, remote_sdp, stream_index): Starts the stream. This method will be called as soon is known to be used in the Session (eg. only called for an incoming proposal if the local party accepts the proposed stream). If starting succeeds, the stream must send a MediaStreamDidStart notification or a MediaStreamDidFail notification otherwise.
local_sdp:
The FrozenSDPSession which is used by the local endpoint.
remote_sdp:
The FrozenSDPSession which is used by the remote endpoint.
stream_index:
An integer representing the index within the list of media streams within the whole SDP which this stream is represented by.

validate_update(self, remote_sdp, stream_index): This method will be called when a re-INVITE is received which changes the parameters of the stream within the SDP. The stream must return True if the changes are acceptable or False otherwise. If any changed streams return False for a re-INVITE, the re-INVITE will be refused with a negative response. This means that streams must not changed any internal data when this method is called as the update is not guaranteed to be applied even if the stream returns True.
remote_sdp:
The FrozenSDPSession which is used by the remote endpoint.
stream_index:
An integer representing the index within the list of media streams within the whole SDP which this stream is represented by.

update(self, local_sdp, remote_sdp, stream_index): This method is called when the an SDP negotiation initiated by either the local party or the remote party succeeds. The stream must update its internal state according to the new SDP in use.
local_sdp:
The FrozenSDPSession which is used by the local endpoint.
remote_sdp:
The FrozenSDPSession which is used by the remote endpoint.
stream_index:
An integer representing the index within the list of media streams within the whole SDP which this stream is represented by.

hold(self): Puts the stream on hold if supported by the stream. Typically used by audio and video streams. The stream must immediately stop sending/receiving data and calls to get_local_media() following calls to this method must return an SDP which reflects the new hold state.

unhold(self): Takes the stream off hold. Typically used by audio and video streams. Calls to get_local_media() following calls to this method must return an SDP which reflects the new hold state.

deactivate(self): This method is called on a stream just before the stream will be removed from the Session (either as a result of a re-INVITE or a BYE). This method is needed because it avoids a race condition with streams using stateful protocols such as TCP: the stream connection might be terminated before the SIP signalling announces this due to network routing inconsistencies and the other endpoint would not be able to distinguish between this case and an error which caused the stream transport to fail. The stream must not take any action, but must consider that the transport being closed by the other endpoint after this method was called as a normal situation rather than an error condition.

end(self): Ends the stream. This must close the underlying transport connection. The stream must send a MediaStreamWillEnd just after this method is called and a MediaStreamDidEnd as soon as the operation is complete. This method is always be called by the Session on the stream if at least the initialize() method has been called. This means that once a stream sends the MediaStreamDidFail notification, the Session will still call this method.

attributes

type (class attribute): A string identifying the stream type (eg: "audio", "video").

priority (class attribute): An integer value indicating the stream priority relative to the other streams types (higher numbers have higher priority).

hold_supported: True if the stream supports hold

on_hold_by_local: True if the stream is on hold by the local party

on_hold_by_remote: True if the stream is on hold by the remote

on_hold: True if either on_hold_by_local or on_hold_by_remote is true

notifications

These notifications must be generated by all streams in order for the Session to know the state of the stream.

MediaStreamDidInitialize: Sent when the stream has been successfully initialized.

MediaStreamDidStart: Sent when the stream has been successfully started.

MediaStreamDidFail: Sent when the stream has failed either as a result of calling one of its methods, or during the normal operation of the stream (such as the transport connection being closed).

MediaStreamWillEnd: Sent immediately after the end() method is called.

MediaStreamDidEnd: Sent when the end() method finished closing the stream.

MediaStreamRegistry

The MediaStream registry is a collection of classes which implement IMediaStream. This collection is used by the Session to select a stream class for instantiation in the case of an incomming session. The streams are included in the collection in the descending order of their priority. Thus, streams with a higher priority will be tried first by the Session. This object is a Singleton so references to the same object can be obtained by a simple instantiation.

There are several pre-built streams based on the IMediaStream API:

sipsimple.streams.rtp.AudioStream - Audio stream based on RTP
sipsimple.streams.msrp.ChatStream - Chat stream based on MSRP
sipsimple.streams.msrp.FileTransferStream - File Transfer stream based on MSRP
sipsimple.streams.msrp.DesktopSharingStream - Desktop Sharing stream based on VNC over MSRP

Other streams which are created by the application must be registered in this registry. For a simple way of doing this, see MediaStreamRegistrar.

methods

__init__(self): Instantiate the MediaStreamRegistry. This will be called just once when first (and only) instance is created.

__iter__(self): This method allows the registry to be iterated through and will return classes which were registered to it.

add(self, cls): Add cls to the registry of streams. The class must implement the IMediaStream interface.

MediaStreamRegistrar

This is a convenience metaclass which automatically registers a defined class with the MediaStreamRegistry. In order to use this class, one simply needs to use it as the metaclass of the new stream.

from zope.interface import implements

from sipsimple.streams import IMediaStream, MediaStreamRegistrar


class MyStream(object):
  __metaclass__ = MediaStreamRegistrar

  implements(IMediaStream)
  
[...]

AudioStream

Implemented in sipsimple/streams/rtp.py

The AudioStream is an implementation of IMediaStream which supports audio data using the AudioTransport and RTPTransport of the SIP core. As such, it provides all features of these objects, including ICE negotiation. An example SDP created using the AudioStream is provided below:

Content-Type: application/sdp
Content-Length:  1093

v=0
o=- 3467525278 3467525278 IN IP4 192.168.1.6
s=blink-0.10.7-beta
c=IN IP4 80.101.96.20
t=0 0
m=audio 55328 RTP/AVP 104 103 102 3 9 0 8 101
a=rtcp:55329 IN IP4 80.101.96.20
a=rtpmap:104 speex/32000
a=rtpmap:103 speex/16000
a=rtpmap:102 speex/8000
a=rtpmap:3 GSM/8000
a=rtpmap:9 G722/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15
a=crypto:1 AES_CM_128_HMAC_SHA1_80 inline:esI6DbLY1+Aceu0JNswN9Z10DcFx5cZwqJcu91jb
a=crypto:2 AES_CM_128_HMAC_SHA1_32 inline:SHuEMm1BYJqOF4udKl73EaCwnsI57pO86bYKsg70
a=ice-ufrag:2701ed80
a=ice-pwd:6f8f8281
a=candidate:S 1 UDP 31 80.101.96.20 55328 typ srflx raddr 192.168.1.6 rport 55328
a=candidate:H 1 UDP 23 192.168.1.6 55328 typ host
a=candidate:H 1 UDP 23 10.211.55.2 55328 typ host
a=candidate:H 1 UDP 23 10.37.129.2 55328 typ host
a=candidate:S 2 UDP 30 80.101.96.20 55329 typ srflx raddr 192.168.1.6 rport 55329
a=candidate:H 2 UDP 22 192.168.1.6 55329 typ host
a=candidate:H 2 UDP 22 10.211.55.2 55329 typ host
a=candidate:H 2 UDP 22 10.37.129.2 55329 typ host
a=sendrecv

As an implementation of IAudioPort, an AudioStream can be added to an AudioBridge to send or to read audio data to/from other audio objects. It is connected to the voice AudioMixer (SIPApplication.voice_audio_mixer) so it can only be added to bridges using the same AudioMixer. It also contains an AudioBridge on the bridge attribute which always contains an AudioDevice corresponding to the input and output devices; when the stream is active (started and not on hold), the bridge also contains the stream itself and when recording is active, the stream contains a WaveRecorder which records audio data.

methods

start_recording(self, filename=None): If an audio stream is present within this session, calling this method will record the audio to a .wav file. Note that when the session is on hold, nothing will be recorded to the file. Right before starting the recording a SIPSessionWillStartRecordingAudio notification will be emitted, followed by a SIPSessionDidStartRecordingAudio. This method may only be called while the stream is started.
filename:
The name of the .wav file to record to. If this is set to None, a default file name including the session participants and the timestamp will be generated using the directory defined in the configuration.

stop_recording(self): This will stop a previously started recording. Before stopping, a SIPSessionWillStopRecordingAudio notification will be sent, followed by a SIPSessionDidStopRecordingAudio.

send_dtmf(self, digit): If the audio stream is started, sends a DTMF digit to the remote party.
digit:
This should a string of length 1, containing a valid DTMF digit value (0-9, A-D, * or #).

attributes

sample_rate: If the audio stream was started, this attribute contains the sample rate of the audio negotiated.

codec: If the audio stream was started, this attribute contains the name of the audio codec that was negotiated.

srtp_active: If the audio stream was started, this boolean attribute indicates if SRTP is currently being used on the stream.

ice_active: True if the ICE candidates negotiated are being used, False otherwise.

local_rtp_address: If an audio stream is present within the session, this attribute contains the local IP address used for the audio stream.

local_rtp_port: If an audio stream is present within the session, this attribute contains the local UDP port used for the audio stream.

remote_rtp_address_sdp: If the audio stream was started, this attribute contains the IP address that the remote party gave to send audio to.

remote_rtp_port_sdp: If the audio stream was started, this attribute contains the UDP port that the remote party gave to send audio to.

remote_rtp_address_received: If the audio stream was started, this attribute contains the remote IP address from which the audio stream is being received.

remote_rtp_port_received: If the audio stream was started, this attribute contains the remote UDP port from which the audio stream is being received.

local_rtp_candidate_type: The local ICE candidate type which was selected by the ICE negotiation if it succeeded and None otherwise.

remote_rtp_candidate_type: The remote ICE candidate type which was selected by the ICE negotiation if it succeeded and None otherwise.

recording_filename: If the audio stream is currently being recorded to disk, this property contains the name of the .wav file being recorded to.

notifications

AudioStreamDidChangeHoldState: Will be sent when the hold state is changed as a result of either a SIP message received on the network or the application calling the hold()/unhold() methods on the Session this stream is part of.
timestamp:
A datetime.datetime object indicating when the notification was sent.
originator:
A string representing the party which requested the hold change, "local" or "remote"
on_hold:
A boolean indicating the new hold state from the point of view of the originator.

AudioStreamWillStartRecordingAudio: Will be sent when the application requested that the audio stream be recorded to a .wav file, just before recording starts.
timestamp:
A datetime.datetime object indicating when the notification was sent.
filename:
The full path to the .wav file being recorded to.

AudioStreamDidStartRecordingAudio: Will be sent when the application requested that the audio stream be recorded to a .wav file, just after recording started.
timestamp:
A datetime.datetime object indicating when the notification was sent.
filename:
The full path to the .wav file being recorded to.

AudioStreamWillStopRecordingAudio: Will be sent when the application requested ending the recording to a .wav file, just before recording stops.
timestamp:
A datetime.datetime object indicating when the notification was sent.
filename:
The full path to the .wav file being recorded to.

AudioStreamDidStopRecordingAudio: Will be sent when the application requested ending the recording to a .wav file, just after recording stoped.
timestamp:
A datetime.datetime object indicating when the notification was sent.
filename:
The full path to the .wav file being recorded to.

AudioStreamDidChangeRTPParameters: This notification is sent when the RTP parameters are changed, such as codec, sample rate, RTP port etc.
timestamp:
A datetime.datetime object indicating when the notification was sent.

AudioStreamGotDTMF: Will be send if there is a DMTF digit received from the remote party on the audio stream.
timestamp:
A datetime.datetime object indicating when the notification was sent.
digit:
The DTMF digit that was received, in the form of a string of length 1.

AudioStreamICENegotiationStateDidChange: This notification is proxied from the RTPTransport and as such has the same data as the RTPTransportICENegotiationStateDidChange.

AudioStreamICENegotiationDidSucceed: This notification is proxied from the RTPTransport and as such has the same data as the RTPTransportICENegotiationDidSucceed.

AudioStreamICENegotiationDidFail: This notification is proxied from the RTPTransport and as such has the same data as the RTPTransportICENegotiationDidFail.

MSRPStreamBase

Implemented in sipsimple/streams/msrp.py

The MSRPStreamBase is used as a base class for streams using the MSRP protocol. Within the SIP SIMPLE middleware, this hold for the ChatStream, FileTransferStream and DesktopSharingStream classes, however the application can also make use of this class to implement some other streams based on the MSRP protocol as a transport.

methods

Of the methods defined by the IMediaStream interface, only the new_from_sdp method is not implemented in this base class and needs to be provided by the subclasses. Also, the subclasses can defined methods of the form _handle_XXX, where XXX is a MSRP method name in order to handle incoming MSRP requests. Also, since this class registers as an observer for itself, it will receive the notifications it sends so subclasses can define methods having the signature _NH_<notification name>(self, notification) as used throughout the middleware in order to do various things at the different points within the life-cycle of the stream.

attributes

The attributes defined in the IMediaStream interface which are not provided by this class are:

type
priority

In addition, the following attributes need to be defined in the subclass in order for the MSRPStreamBase class to take the correct decisions

media_type: The media type as included in the SDP (eg. "message", "application").

accept_types: A list of the MIME types which should be accepted by the stream (this is also sent within the SDP).

accept_wrapped_types: A list of the MIME types which should be accepted by the stream while wrapped in a message/cpim envelope.

use_msrp_session: A boolean indicating whether or not an MSRPSession should be used.

notifications

While not technically notifications of MSRPStreamBase, these notifications are sent from the middleware on behalf of the MSRPTransport used by a stream in the former case, and anonymously in the latter.

MSRPTransportTrace: This notification is sent when an MSRP message is received for logging purposes.
timestamp:
A datetime.datetime object indicating when the notification was sent.
direction:
The direction of the message, "incoming" or "outgoing".
data:
The MSRP message as a string.

MSRPLibraryLog: This notification is sent anonymously whenever the MSRP library needs to log any information.
timestamp:
A datetime.datetime object indicating when the notification was sent.
message:
The log message as a string.
level:
The log level at which the message was written. One of the levels DEBUG, INFO, WARNING, ERROR, CRITICAL from the application.log.level object which is part of the python-application library.

ChatStream

Implemented in sipsimple/streams/msrp.py

sipsimple.streams.msrp.ChatStream implements session-based Instant Messaging (IM) over MSRP. This class performs the following functions:

automatically wraps outgoing messages with Message/CPIM if that's necessary according to accept-types
unwraps incoming Message/CPIM messages; for each incoming message, the ChatStreamGotMessage notification is posted
composes iscomposing payloads and reacts to those received by sending the ChatStreamGotComposingIndication notification

An example of an SDP created using this class follows:

Content-Type: application/sdp
Content-Length:   283

v=0
o=- 3467525214 3467525214 IN IP4 192.168.1.6
s=blink-0.10.7-beta
c=IN IP4 192.168.1.6
t=0 0
m=message 2855 TCP/TLS/MSRP *
a=path:msrps://192.168.1.6:2855/ca7940f12ddef14c3c32;tcp
a=accept-types:message/cpim text/* application/im-iscomposing+xml
a=accept-wrapped-types:*

methods

__init__(self, account, direction='sendrecv'): Initializes the ChatStream instance.

send_message(self, content, content_type='text/plain', recipients=None, courtesy_recipients=None, subject=None, timestamp=None, required=None, additional_headers=None): Sends an IM message. Prefer Message/CPIM wrapper if it is supported. If called before the connection was established, the messages will be queued until the stream starts. Returns the generated MSRP message ID.
content:
The content of the message.
content_type:
Content-Type of wrapped message if Message/CPIM is used (Content-Type of MSRP message is always Message/CPIM in that case); otherwise, Content-Type of MSRP message.
recipients:
The list of CPIMIdentity objects which will be used for the To header of the CPIM wrapper. Used to override the default which depends on the remote identity. May only differ from the default one if the remote party supports private messages. If it does not, a ChatStreamError will be raised.
courtesy_recipients:
The list of CPIMIdentity objects which will be used for the cc header of the CPIM wrapper. May only be specified if the remote party supports private messages and CPIM is supported. If it does not, a ChatStreamError will be raised.
subject:
A string or MultilingualText which specifies the subject and its translations to be added to the CPIM message. If CPIM is not supported, a ChatStreamError will be raised.
required:
A list of strings describing the required capabilities that the other endpoint must support in order to understand this CPIM message. If CPIM is not supported, a ChatStreamError will be raised.
additional_headers:
A list of MSRP header objects which will be added to this CPIM message. If CPIM is not supported, a ChatStreamError will be raised.
timestamp:
A datetime.datetime object representing the timestamp to put on the CPIM wrapper of the message. When set to None, a default one representing the current moment will be added.

These MSRP headers are used to enable end-to-end success reports and to disable hop-to-hop successful responses:
Failure-Report: partial
Success-Report: yes

send_composing_indication(self, state, refresh, last_active=None, recipients=None): Sends an is-composing message to the listed recipients.
state:
The state of the endpoint, "active" or "idle".
refresh:
How often the local endpoint will send is-composing indications to keep the state from being reverted to "idle".
last_active:
A datatime.datetime object representing the moment when the local endpoint was last active.
recipients:
The list of CPIMIdentity objects which will be used for the To header of the CPIM wrapper. Used to override the default which depends on the remote identity. May only differ from the default one if the remote party supports private messages. If it does not, a ChatStreamError will be raised.

notifications

ChatStreamGotMessage: Sent whenever a new incoming message is received,
timestamp:
A datetime.datetime object indicating when the notification was sent.
message:
A ChatMessage or CPIMMessage instance, depending on whether a CPIM message was received or not.

ChatStreamDidDeliverMessage: Sent when a successful report is received.
timestamp:
A datetime.datetime object indicating when the notification was sent.
message_id:
Text identifier of the message.
code:
The status code received. Will always be 200 for this notification.
reason:
The status reason received.
chunk:
A msrplib.protocol.MSRPData instance providing all the MSRP information about the report.

ChatStreamDidNotDeliverMessage: Sent when a failure report is received.
timestamp:
A datetime.datetime object indicating when the notification was sent.
message_id:
Text identifier of the message.
code:
The status code received.
reason:
The status reason received.
chunk:
A msrplib.protocol.MSRPData instance providing all the MSRP information about the report.

ChatStreamDidSendMessage: Sent when an outgoing message has been sent.
timestamp:
A datetime.datetime object indicating when the notification was sent.
message:
A msrplib.protocol.MSRPData instance providing all the MSRP information about the sent message.

ChatStreamGotComposingIndication: Sent when a is-composing payload is received.
timestamp:
A datetime.datetime object indicating when the notification was sent.
state:
The state of the endpoint, "active" or "idle".
refresh:
How often the remote endpoint will send is-composing indications to keep the state from being reverted to "idle". May be None.
last_active:
A datatime.datetime object representing the moment when the remote endpoint was last active. May be None.
content_type:
The MIME type of message being composed. May be None.
sender:
The ChatIdentity or CPIMIdentity instance which identifies the sender of the is-composing indication.

FileSelector

The FileSelector is used to contain information about a file tranfer using the FileTransferStream documented below.

methods

__init__(self, name=None, type=None, size=None, hash=None, fd=None): Instantiate a new FileSelector. All the arguments are also available as attributes.
name:
The filename (should be just the base name).
type:
The type of the file.
size:
The size of the file in bytes.
hash:
The hash of the file in the following format: hash:sha-1:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX, where X is a hexadecimal digit. Currently, only SHA1 hashes are supported according to the RFC.
fd:
A file descriptor if the application has already opened the file.

parse(cls, string): Parses a file selector from the SDP file-selector a attribute and returns a FileSelector instance.

for_file(cls, path, content_type, compute_hash=True): Returns a FileSelector instance for the specified file. The file identified by the path must exist. Note that if compute_hash is True this method will block while the hash is computed, a potentially long operation for large files.
path:
The full path to the file.
content_type:
An optional MIME type which is to be included in the file-selector.
compute_hash:
Whether or not this method should compute the hash of the file.

attributes

sdp_repr: The SDP representation of the file-selector according to the RFC. This should be the value of the file-selector SDP attribute.

FileTransferStream

Implemented in sipsimple/streams/msrp.py

The FileTransferStream supports file transfer over MSRP according to RFC5547. An example of SDP constructed using this stream follows:

Content-Type: application/sdp
Content-Length:   383

v=0
o=- 3467525166 3467525166 IN IP4 192.168.1.6
s=blink-0.10.7-beta
c=IN IP4 192.168.1.6
t=0 0
m=message 2855 TCP/TLS/MSRP *
a=path:msrps://192.168.1.6:2855/e593357dc9abe90754bd;tcp
a=sendonly
a=accept-types:*
a=accept-wrapped-types:*
a=file-selector:name:"reblink.pdf" type:com.adobe.pdf size:268759 hash:sha1:60:A1:BE:8D:71:DB:E3:8E:84:C9:2C:62:9E:F2:99:78:9D:68:79:F6

methods

__init__(self, account, file_selector=None): Instantiate a new FileTransferStream. If this is constructed by the application for an outgoing file transfer, the file_selector argument must be present.
account:
The sipsimple.account.Account or sipsimple.account.BonjourAccount instance which will be associated with the stream.
file_selector:
The FileSelector instance which represents the file which is to be transferred.

notifications

FileTransferStreamDidDeliverChunk: This notification is sent for an outgoing file transfer when a success report is received about part of the file being transferred.
timestamp:
A datetime.datetime object indicating when the notification was sent.
message_id:
The MSRP message ID of the file transfer session.
chunk:
An msrplib.protocol.MSRPData instance represented the received REPORT.
code:
The status code received. Will always be 200 for this notification.
reason:
The status reason received.
transferred_bytes:
The number of bytes which have currently been successfully transferred.
file_size:
The size of the file being transferred.

FileTransferStreamDidNotDeliverChunk: timestamp:
A datetime.datetime object indicating when the notification was sent. This notification is sent for an outgoing file transfer when a failure report is received about part of the file being transferred.
message_id:
The MSRP message ID of the file transfer session.
chunk:
An msrplib.protocol.MSRPData instance represented the received REPORT.
code:
The status code received.
reason:
The status reason received.

FileTransferStreamDidFinish: This notification is sent when the incoming or outgoing file transfer is finished.
timestamp:
A datetime.datetime object indicating when the notification was sent.

FileTransferStreamGotChunk: This notificaiton is sent for an incoming file transfer when a chunk of file data is received.
timestamp:
A datetime.datetime object indicating when the notification was sent.
content:
The file part which was received, as a str.
content_type:
The MIME type of the file which is being transferred.
transferred_bytes:
The number of bytes which have currently been successfully transferred.
file_size:
The size of the file being transferred.

IDesktopSharingHandler

This interface is used to describe the interface between a IDesktopSharingHandler, which is responsible for consuming and producing RFB data, and the DesktopSharingStream which is responsible for transporting the RFB data over MSRP. The middleware provides four implementations of this interface:

InternalVNCViewerHandler
InternalVNCServerHandler
ExternalVNCViewerHandler
ExternalVNCServerHandler

methods

initialize(self, stream): This method will be called by the DesktopSharingStream when the stream has been started and RFB data can be transported. The stream has two attributes which are relevant to the IDesktopSharingHandler: incoming_queue and outgoing_queue. These attributes are eventlet.coros.queue instances which are used to transport RFB data between the stream and the handler.

attributes

type: "active" or "passive" depending on whether the handler represents a VNC viewer or server respectively.

notifications

DesktopSharingHandlerDidFail: This notification must be sent by the handler when an error occurs to notify the stream that it should fail.
context:
A string describing when the handler failed, such as "reading", "sending" or "connecting".
failure:
A twisted.python.failure.Failure instance describing the exception which led to the failure.
reason:
A string describing the failure reason.

InternalVNCViewerHandler

This is a concrete implementation of the IDesktopSharingHandler interface which can be used for a VNC viewer implemented within the application.

methods

send(self, data): Sends the specified data to the stream in order for it to be transported over MSRP to the remote endpoint.
data:
The RFB data to be transported over MSRP, in the form of a str.

notifications

DesktopSharingStreamGotData: This notification is sent when data is received over MSRP.
data:
The RFB data from the remote endpoint, in the form of a str.

InternalVNCServerHandler

This is a concrete implementation of the IDesktopSharingHandler interface which can be used for a VNC server implemented within the application.

methods

send(self, data): Sends the specified data to the stream in order for it to be transported over MSRP to the remote endpoint.
data:
The RFB data to be transported over MSRP, in the form of a str.

notifications

DesktopSharingStreamGotData: This notification is sent when data is received over MSRP.
data:
The RFB data from the remote endpoint, in the form of a str.

ExternalVNCViewerHandler

This implementation of IDesktopSharingHandler can be used for an external VNC viewer which connects to a VNC server using TCP.

methods

__init__(self, address=("localhost", 0), connect_timeout=3): This instantiates a new ExternalVNCViewerHandler which is listening on the provided address, ready for the external VNC viewer to connect to it via TCP. After this method returns, the attribute address can be used to find out exactly on what address and port the handler is listening on. The handler will only accept one conenction on this address.
address:
A tuple containing an IP address/hostname and a port on which the handler should listen. Any data received on this socket will then be forwarded to the stream and any data received from the stream will be forwarded to this socket.

attributes

address: A tuple containing an IP address and a port on which the handler is listening.

ExternalVNCServerHandler

This implementation of IDesktopSharingHandler can be used for an external VNC server to which handler will connect using TCP.

methods

__init__(self, address, connect_timeout=3): This instantiates a new ExternalVNCServerHandler which will connect to the provided address on which a VNC server must be listening before the stream using this handler starts.
address:
A tuple containing an IP address/hostname and a port on which the VNC server will be listening. Any data received on this socket will then be forwared to the stream and any data received form the stream will be forwarded to this socket.
connect_timeout:
How long to wait to connect to the VNC server before giving up.

DesktopSharingStream

Implemented in sipsimple/streams/msrp.py

This stream implements desktop sharing using MSRP as a transport protocol for RFB data.

There is no standard defining this usage but is fairly easy to implement in clients that already support MSRP. To traverse a NAT-ed router, a MSRP relay configured for the called party domain is needed. Below is an example of the Session Description Protocol used for establishing a Desktop sharing session:

m=application 2855 TCP/TLS/MSRP *
a=path:msrps://10.0.1.19:2855/b599b22d1b1d6a3324c8;tcp
a=accept-types:application/x-rfb
a=setup:active

methods

__init__(self, acount, handler): Instantiate a new DesktopSharingStream.
account:
The sipsimple.account.Account or sipsimple.account.BonjourAccount instance this stream is associated with.
handler:
An object implementing the IDesktopSharingHandler interface which will act as the handler for RFB data.

attributes

handler: This is a writable property which can be used to get or set the object implementing IDesktopSharingHandler which acts as the handler for RFB data. For incoming DesktopSharingStreams, this must be set by the application before the stream starts.

incoming_queue: A eventlet.coros.queue instance on which incoming RFB data is written. The handler should wait for data on this queue.

outgoing_queue: A eventlet.coros.queue instance on which outgoing RFB data is written. The handler should write data on this queue.

Address Resolution

The SIP SIMPLE middleware offers the sipsimple.lookup module which contains an implementation for doing DNS lookups for SIP proxies, MSRP relays and STUN servers. The interface offers both an asynchronous and synchronous interface. The asynchronous interface is based on notifications, while the synchronous one on green threads. In order to call the methods in a asynchronous manner, you just need to call the method and wait for the notification which is sent on behalf of the DNSLookup instance. The notifications sent by the DNSLookup object are DNSLookupDidSucceed and DNSLookupDidFail. In order to call the methods in a synchronous manner, you need to call the wait method on the object returned by the methods of DNSLookup. This wait method needs to be called from a green thread and will either return the result of the lookup or raise an exception.

DNS Lookup

This object implements DNS lookup support for SIP proxies according to RFC3263 and MSRP relay and STUN server lookup using SRV records. The object initially does NS record queries in order to determine the authoritative nameservers for the domain requested; these authoritative nameservers will then be used for NAPTR, SRV and A record queries. If this fails, the locally configured nameservers are used. The reason for doing this is that some home routers have broken NAPTR and/or SRV query support.

methods

__init__(self): Instantiate a new DNSLookup object.

lookup_service(self, uri, service, timeout=3.0, lifetime=15.0): Perform an SRV lookup followed by A lookups for MSRP relays or STUN servers depending on the service parameter. If SRV queries on the uri.host domain fail, an A lookup is performed on it and the default port for the service is returned. Only the uri.host attribute is used. The return value is a list of (host, port) tuples.
uri:
A (Frozen)SIPURI from which the host attribute is used for the query domain.
service:
The service to lookup servers for, "msrprelay" or "stun".
timeout:
How many seconds to wait for a response from a nameserver.
lifetime:
How many seconds to wait for a response from all nameservers in total.

lookup_sip_proxy(self, uri, supported_transports, timeout=3.0, lifetime=15.0): Perform a RFC3263 compliant DNS lookup for a SIP proxy using the URI which is considered to point to a host if either the host attribute is an IP address, or the port is present. Otherwise, it is considered a domain for which NAPTR, SRV and A lookups are performed. If NAPTR or SRV queries fail, they fallback to using SRV and A queries. If the transport parameter is present in the URI, this will be used as far as it is part of the supported transports. If the URI has a sips schema, then only the TLS transport will be used as far as it doesn't conflict with the supported transports or the transport parameter. The return value is a list of Route objects containing the IP address, port and transport to use for routing in the order of preference given by the supported_transports argument.
uri:
A (Frozen)SIPURI from which the host, port, parameters and secure attributes are used.
supported_transports:
A sublist of ['udp', 'tcp', 'tls'] in the application's order of preference.
timeout:
How many seconds to wait for a response from a nameserver.
lifetime:
How many seconds to wait for a response from all nameservers in total.

notifications

DNSLookupDidSucceed: This notification is sent when one of the lookup methods succeeds in finding a result.
timestamp:
A datetime.datetime object indicating when the notification was sent.
result:
The result of the DNS lookup in the format described in each method.

DNSLookupDidFail: This notification is sent when one of the lookup methods fails in finding a result.
timestamp:
A datetime.datetime object indicating when the notification was sent.
error:
A str object describing the error which resulted in the DNS lookup failure.

DNSLookupTrace: This notification is sent several times during a lookup process for each individual DNS query.
timestamp:
A datetime.datetime object indicating when the notification was sent.
query_type:
The type of the query, "NAPTR", "SRV", "A", "NS" etc.
query_name:
The name which was queried.
answer:
The answer returned by dnspython, or None if an error occurred.
error:
The exception which caused the query to fail, or None if no error occurred.
context:
The name of the method which was called on the DNSLookup object.
service:
The service which was queried for, only available when context is "lookup_service".
uri:
The uri which was queried for.

Route

This is a convinience object which contains sufficient information to identify a route to a SIP proxy. This object is returned by DNSLookup.lookup_sip_proxy and can be used with the Session or a (Frozen)RouteHeader can be easily constructed from it to pass to one of the objects in the SIP core handling SIP dialogs/transactions (Invitation, Subscription, Request, Registration, Message, Publication). This object has three attributes which can be set in the constructor or after it was instantiated. They will only be documented as arguments to the constructor.

methods

__init__(self, address, port=None, transport='udp'): Creates the Route object with the specified parameters as attributes. Each of these attributes can be accessed on the object once instanced.
address:
The IPv4 address that the request in question should be sent to as a string.
port:
The port to send the requests to, represented as an int, or None if the default port is to be used.
transport:
The transport to use, this can be a string of either "udp", "tcp" or "tls" (case insensitive).

get_uri(self)

Returns a SIPURI object which contains the adress, port and transport as parameter. This can be used to easily construct a RouteHeader:

    route = Route("1.2.3.4", port=1234, transport="tls")
    route_header = RouteHeader(route.get_uri())

SIP Accounts

Account Management is implemented in sipsimple/account.py (sipsimple.account module) and offers support for SIP accounts registered at SIP providers and SIP bonjour accounts which are discovered using mDNS.

AccountManager

The sipsimple.account.AccountManager is the entity responsible for loading and keeping track of the existing accounts. It is a singleton and can be instantiated anywhere, obtaining the same instance. It cannot be used until its start method has been called.

methods

__init__(self): The __init__ method allows the AccountManager to be instantiated without passing any parameters. A reference to the AccountManager can be obtained anywhere before it is started.

start(self): This method will load all the existing accounts from the configuration. If the Engine is running, the accounts will also activate. This method can only be called after the ConfigurationManager has been started. A SIPAccountManagerDidAddAccount will be sent for each account loaded. This method is called automatically by the SIPApplication when it initializes all the components of the middleware.

stop(self): Calling this method will deactivate all accounts managed by the AccountManager. This method is called automatically by the SIPApplication when it stops.

has_account(self, id): This method returns True if an account which has the specifed SIP ID (must be a string) exists and False otherwise.

get_account(self, id): Returns the account (either an Account instance or the BonjourAccount instance) with the specified SIP ID. Will raise a KeyError if such an account does not exist.

get_accounts(self): Returns a list containing all the managed accounts.

iter_accounts(self): Returns an iterator through all the managed accounts.

find_account(self, contact_uri): Returns an account with matches the specified contact_uri which must be a sipsimple.core.SIPURI instance. Only the accounts with the enabled flag set will be considered. Returns None if such an account does not exist.

notifications

SIPAccountManagerDidAddAccount: This notification is sent when a new account becomes available to the AccountManager. The notification is also sent when the accounts are loaded from the configuration.
timestamp:
A datetime.datetime object indicating when the notification was sent.
account:
The account object which was added.

SIPAccountManagerDidRemoveAccount: This notification is sent when an account is deleted using the delete method.
timestamp:
A datetime.datetime object indicating when the notification was sent.
account:
The account object which was deleted.

SIPAccountManagerDidChangeDefaultAccount: This notification is sent when the default account changes.
timestamp:
A datetime.datetime object indicating when the notification was sent.
old_account:
This is the account object which used to be the default account.
account:
This is the account object which is the new default account.

Account

The sipsimple.account.Account objects represent the SIP accounts which are registered at SIP providers. It has a dual purpose: it acts as both a container for account-related settings and as a complex object which can be used to interact with various per-account functions, such as presence, registration etc. This page documents the latter case, while the former is explained in the Configuration API.

There is exactly one instance of Account per SIP account used and it is uniquely identifiable by its SIP ID, in the form user@domain. It is a singleton, in the sense that instantiating Account using an already used SIP ID will return the same object. However, this is not the recommended way of accessing accounts, as this can lead to creation of new ones; the recommended way is by using the AccountManager. The next sections will use a lowercase, monospaced account to represent an instance of Account.

states

The Account objects have a setting flag called enabled which, if set to False will deactivate it: none of the internal functions will work in this case; in addition, the application using the middleware should not do anything with a disabled account. After changing it's value, the save() method needs to be called, as the flag is a setting and will not be used until this method is called:

account.enabled = True
account.save()

The Account objects will activate automatically when they are loaded/created if the enabled flag is set to True and the sipsimple.engine.Engine is running; if it is not running, the accounts will activate after the engine starts.

In order to create a new account, just create a new instance of Account with an id which doesn't belong to any other account.

The other functions of Account which run automatically have other enabled flags as well. They will only be activated when both the global enabled flag is set and the function-specific one. These are:

Account.registration.enabled: This flag controls the automatic registration of the account. The notifications SIPAccountRegistrationDidSucceed, SIPAccountRegistrationDidFail and SIPAccountRegistrationDidEnd are used to inform the status of this registration.

Account.presence.enabled: This flag controls the automatic subscription to buddies for the presence event and the publication of data in this event. (Not implemented yet)

Account.dialog_event.enabled: This flag controls the automatic subscription to buddies for the dialog-info event and the publication of data in this event. (Not implemented yet)

Account.message_summary.enabled: This flag controls the automatic subscription to the message-summary event in order to find out about voicemail messages. (Not implemented yet)

The save() method needs to be called after changing these flags in order for them to take effect. The methods available on Account objects are inherited from SettingsObject.

attributes

The following attributes can be used on an Account object and need to be considered read-only.

id

This attribute is of type sipsimple.configuration.datatypes.SIPAddress (a subclass of str) and contains the SIP id of the account. It can be used as a normal string in the form user@domain, but it also allows access to the components via the attributes username and domain.

  account.id # 'alice@example.com'
  account.id.username # 'alice'
  account.id.domain # 'example.com'

contact

This attribute can be used to construct the Contact URI for SIP requests sent on behalf of this account. It's type is sipsimple.account.ContactURI which is a subclass of sipsimple.configuration.datatypes.SIPAddress. In addition to the attributes defined in SIPAddress, it can be indexed by a string representing a transport ('udp', 'tcp' or 'tls') which will return a sipsimple.core.SIPURI object with the appropriate port and transport parameter. The username part is a randomly generated 8 character string consisting of lowercase letters; the domain part is the IP address on which the Engine is listening (as specified by the SIPSimpleSettings.local_ip setting).

  account.contact # 'hnfkybrt@10.0.0.1'
  account.contact.username # 'hnfkybrt'
  account.contact.domain # '10.0.0.1'
  account.contact['udp'] # <SIPURI "sip:hnfkybrt@10.0.0.1:53024">
  account.contact['tls'] # <SIPURI "sip:hnfkybrt@10.0.0.1:54478;transport=tls">

credentials

This attribute is of type sipsimple.core.Credentials which is built from the id.username attribute and the password setting of the Account. Whenever this setting is changed, this attribute is updated.

  account.credentials # <Credentials for 'alice'>

uri

This attribute is of type sipsimple.core.SIPURI which can be used to form a FromHeader associated with this account. It contains the SIP ID of the account.

  account.uri # <SIPURI "sip:alice@example.com">

notifications

CFGSettingsObjectDidChange: This notification is sent when the save() method is called on the account after some of the settings were changed. As the notification belongs to the SettingsObject class, it is exaplained in detail in SettingsObject Notifications.

SIPAccountDidActivate: This notification is sent when the Account activates. This can happen when the Account is loaded if it's enabled flag is set and the Engine is running, and at any later time when the status of the Engine changes or the enabled flag is modified.
timestamp:
A datetime.datetime object indicating when the notification was sent.

SIPAccountDidDeactivate: This notification is sent when the Account deactivates. This can happend when the Engine is stopped or when the enabled flag of the account is set to False.
timestamp:
A datetime.datetime object indicating when the notification was sent.

SIPAccountWillRegister

This notification is sent when the account is about to register for the first time.
timestamp:
A datetime.datetime object indicating when the notification was sent.

SIPAccountRegistrationWillRefresh

This notification is sent when a registration is about to be refreshed.
timestamp:
A datetime.datetime object indicating when the notification was sent.

SIPAccountRegistrationDidSucceed: This notification is sent when a REGISTER request sent for the account succeeds (it is also sent for each refresh of the registration). The data contained in this notification is:
timestamp:
A datetime.datetime object indicating when the notification was sent.
contact_header:
The Contact header which was registered.
contact_header_list:
A list containing all the contacts registered for this SIP account.
expires:
The amount in seconds in which this registration will expire.
registrar:
The sipsimple.util.Route object which was used.

SIPAccountRegistrationDidFail: This notification is sent when a REGISTER request sent for the account fails. It can fail either because a negative response was returned or because PJSIP considered the request failed (e.g. on timeout). The data contained in this notification is:
timestamp:
A datetime.datetime object indicating when the notification was sent.
error:
The reason for the failure of the REGISTER request.
timeout:
The amount in seconds as a float after which the registration will be tried again.

SIPAccountRegistrationDidEnd: This notification is sent when a registration is ended (the account is unregistered). The data contained in this notification is:
timestamp:
A datetime.datetime object indicating when the notification was sent.
registration:
The sipsimple.core.Registration object which ended.

SIPAccountRegistrationDidNotEnd: This notification is sent when a registration fails to end (the account is not unregistered). The data contained in this notification is:
timestamp:
A datetime.datetime object indicating when the notification was sent.
code:
The SIP status code received.
reason:
The SIP status reason received.
registration:
The sipsimple.core.Registration object which ended.

SIPAccountRegistrationGotAnswer: This notification is sent whenever a response is received to a sent REGISTER request for this account. The data contained in this notification is:
timestamp:
A datetime.datetime object indicating when the notification was sent.
code:
The SIP status code received.
reason:
The SIP status reason received.
registration:
The sipsimple.core.Registration object which was used.
registrar:
The sipsimple.util.Route object which was used.

BonjourAccount

The sipsimple.account.BonjourAccount represents the SIP account used for P2P mode; it does not interact with any server. The class is a singleton, as there can only be one such account on a system. Similar to the Account, it is used both as a complex object, which implements the functions for bonjour mode, as well as a container for the related settings.

states

The BonjourAccount has an enabled flag which controls whether this account will be used or not. If it is set to False, none of the internal functions will be activated and, in addition, the account should not be used by the application. The bonjour account can only activated if the Engine is running; once it is started, if the enabled flag is set, the account will activate. When the BonjourAccount is activated, it will broadcast the contact address on the LAN and discover its neighbours sending notifications as this happens.

attributes

The following attributes can be used on a BonjourAccount object and need to be considered read-only.

id

This attribute is of type sipsimple.configuration.datatypes.SIPAddress (a subclass of str) and contains the SIP id of the account, which is 'bonjour@local'. It can be used as a normal string, but it also allows access to the components via the attributes username and domain.

  bonjour_account.id # 'bonjour@local'
  bonjour_account.id.username # 'bonjour'
  bonjour_account.id.domain # 'local'

contact

  bonjour_account.contact # 'lxzvgack@10.0.0.1'
  bonjour_account.contact.username # 'lxzvgack'
  bonjour_account.contact.domain # '10.0.0.1'
  bonjour_account.contact['udp'] # <SIPURI "sip:lxzvgack@10.0.0.1:53024">
  bonjour_account.contact['tls'] # <SIPURI "sip:lxzvgack@10.0.0.1:54478;transport=tls">

credentials

This attribute is of type sipsimple.core.Credentials object which is built from the contact.username attribute; the password is set to the empty string.

  bonjour_account.credentials # <Credentials for 'alice'>

uri

This attribute is of type sipsimple.core.SIPURI which can be used to form a FromHeader associated with this account. It contains the contact address of the bonjour account:

  bonjour_account.uri # <SIPURI "sip:lxzvgack@10.0.0.1">

notifications

BonjourAccountRegistrationDidSucceed: This notification is sent when the Bonjour account successfully registers its contact address using mDNS.
name:
The contact address registered.
timestamp:
A datetime.datetime object indicating when the notification was sent.
BonjourAccountRegistrationDidFail: This notification is sent when the Bonjour account fails to register its contact address using mDNS.
code:
The Bonjour error code for the failure reason.
reason:
A human readable error message.

BonjourAccountRegistrationDidEnd: This notification is sent when the Bonjour account unregisters its contact address using mDNS.
timestamp:
A datetime.datetime object indicating when the notification was sent.

BonjourAccountWillRegister: This notification is sent just before the Bonjour account starts the registering process.
timestamp:
A datetime.datetime object indicating when the notification was sent.

BonjourAccountWillRestartDiscovery: This notification is sent when the Bonjour account restarts the discovery process. The application should empty the list of Bonjour neighbours it acquired via the BonjourAccountDidAddNeighbour.
timestamp:
A datetime.datetime object indicating when the notification was sent.

BonjourAccountDidAddNeighbour: This notification is sent when a new Bonjour neighbour is discovered.
display_name:
The name of the neighbour as it is published.
host:
The hostname of the machine from which the Bonjour neighbour registered its contact address.
uri:
The contact URI of the Bonjour neighbour, as a FrozenSIPURI object.
timestamp:
A datetime.datetime object indicating when the notification was sent.

BonjourAccountDidRemoveNeighbour: This notification is sent when a Bonjour neighbour unregisters.
uri:
The contact URI of the Bonjour neighbour, as a FrozenSIPURI object.
timestamp:
A datetime.datetime object indicating when the notification was sent.

CFGSettingsObjectDidChange: This notification is sent when the save() method is called on the account after some of the settings were changed. As the notification belongs to the SettingsObject class, it is exaplained in detail in SettingsObject Notifications.
timestamp:
A datetime.datetime object indicating when the notification was sent.

SIPAccountDidActivate: This notification is sent when the BonjourAccount activates. This can happen when the BonjourAccount is loaded if it's enabled flag is set and the Engine is running, and at any later time when the status of the Engine changes or the enabled flag is modified.
timestamp:
A datetime.datetime object indicating when the notification was sent.

SIPAccountDidDeactivate: This notification is sent when the BonjourAccount deactivates. This can happend when the Engine is stopped or when the enabled flag of the account is set to False.
timestamp:
A datetime.datetime object indicating when the notification was sent.

Audio

The high-level audio API hides the complexity of using the low-level PJMEDIA interface. This is implemented in the sipsimple.audio module and contains the following components:

IAudioPort: an interface describing an object capable of producing and/or consuming audio data.
AudioDevice: an object conforming to the IAudioPort interface which describes a physical audio device.
AudioBridge: a collection of objects conforming to IAudioPort which connects all of them in a full mesh.
WavePlayer: an object conforming to the IAudioPort interface which can playback the audio data from a .wav file.
WaveRecorder: an object conforming to the IAudioPort interface which can record audio data to a .wav file.

IAudioPort

The IAudioPort interface describes an object capable of producing and/or consuming audio data. This can be a dynamic object, which changes its role during its lifetime and notifies such changes using a notification, which is part of the interface.

attributes

mixer: The AudioMixer this audio object is connected to. Only audio objects connected to the same mixer will be able to send audio data from one to another.

consumer_slot: An integer representing the slot (see AudioMixer) which this object uses to consume audio data, or None if this object is not a consumer.

producer_slot: An integer representing the slot (see AudioMixer) which this object uses to produce audio data, or None if this object is not a producer.

notifications

AudioPortDidChangeSlots: This notification needs to be sent by implementations of this interface when the slots it has change, so as to let the AudioBridges it is part of know that reconnections need to be made.
consumer_slot_changed:
A bool indicating whether the consumer slot was changed.
producer_slot_changed:
A bool indicating whether the producer slot was changed.
old_consumer_slot:
The old slot for consuming audio data. Only required if consumer_slot_changed is True.
new_consumer_slot:
The new slot for consuming audio data. Only required if consumer_slot_changed is True.
old_producer_slot:
The old slot for producing audio data. Only required if producer_slot_changed is True.
new_producer_slot:
The new slot for producing audio data. Only required if producer_slot_changed is True.

AudioDevice

The AudioDevice represents the physical audio device which is part of a AudioMixer, implementing the IAudioPort interface. As such, it can be uniquely identified by the mixer it represents.

methods

__init__(self, mixer, input_muted=False, output_muted=False):

Instantiates a new AudioDevice which represents the physical device associated with the specified AudioMixer.
mixer:
The AudioMixer whose physical device this object represents.
input_muted:
A boolean which indicates whether this object should act as a producer of audio data.
output_muted:
A boolean which indicates whether this object should act as a consumer of audio data.

attributes

input_muted: A writable property which controls whether this object should act as a producer of audio data. An AudioPortDidChange slots notification is sent when this attribute is changed to force connections to be reconsidered within the AudioBridges this object is part of.

output_muted: A writable property which controls whether this object should act as a consumer of audio data. An AudioPortDidChange slots notification is sent when this attribute is changed to force connections to be reconsidered within the AudioBridges this object is part of.

AudioBridge

The AudioBridge is the basic component which is able to connect IAudioPort implementations. It acts as a container which connects as the producers to all the consumers which are part of it. An object which is both a producer and a consumer of audio data will not be connected to itself. Being an implementation of IAudioPort itself, an AudioBridge can be part of another AudioBridge. The AudioBridge does not keep strong references to the ports it contains and once the port's reference count reaches 0, it is automatically removed from the AudioBridge.

Note: although this is not enforced, there should never be any cycles when connecting AudioBridges.

methods

__init__(self, mixer): Instantiate a new AudioBridge which uses the specified AudioMixer for mixing.

add(self, port): Add an implementation of IAudioPort to this AudioBridge. This will connect the new port to all the existing ports of the bridge. A port cannot be added more than once to an AudioBridge; thus, this object acts like a set.

remove(self, port): Remove a port from this AudioBridge. The port must have previously been added to the AudioBridge, otherwise a ValueError is raised.

WavePlayer

A WavePlayer is an implementation of IAudioPort which is capable of producing audio data read from a .wav file. This object is completely reusable, as it can be started and stopped any number of times.

methods

__init__(self, mixer, filename, volume=100, loop_count=1, pause_time=0, initial_play=True): Instantiate a new WavePlayer which is capable of playing a .wav file repeatedly. All the parameters are available as attributes of the object, but should not be changed once the object has been started.
mixer:
The AudioMixer this object is connected to.
filename:
The full path to the .wav file from which audio data is to be read.
volume:
The volume at which the file should be played.
loop_count:
The number of times the file should be played, or 0 for infinity.
pause_time:
How many seconds to wait between successive plays of the file.
initial_play:
Whether or not the file to play once the WavePlayer is started, or to wait pause_time seconds before the first play.

start(self): Start playing the .wav file.

stop(self): Stop playing the .wav file immediately.

attributes

is_active: A boolean indicating whether or not this WavePlayer is currently playing.

notifications

WavePlayerDidStart: This notification is sent when the WavePlayer starts playing the file the first time after the start() method has been called.
timestamp:
A datetime.datetime object indicating when the notification was sent.

WavePlayerDidEnd: This notification is sent when the WavePlayer is done playing either as a result of playing the number of times it was told to, or because the stop() method has been called.
timestamp:
A datetime.datetime object indicating when the notification was sent.

WavePlayerDidFail: This notification is sent when the WavePlayer is not capable of playing the .wav file.
timestamp:
A datetime.datetime object indicating when the notification was sent.
error:
The exception raised by the WaveFile which identifies the cause for not being able to play the .wav file.

WaveRecorder

A WaveRecorder is an implementation of IAudioPort is is capable of consuming audio data and writing it to a .wav file. Just like WavePlayer, this object is reusable: once stopped it can be started again, but if the filename attribute is not changed, the previously written file will be overwritten.

methods

__init__(self, mixer, filename): Instantiate a new WaveRecorder.
mixer:
The AudioMixer this WaveRecorder is connected to.
filename:
The full path to the .wav file where this object should write the audio data. The file must be writable. The directories up to the file will be created if possible when the start() method is called.

start(self): Start consuming audio data and writing it to the .wav file. If this object is not part of an AudioBridge, not audio data will be written.

stop(self): Stop consuming audio data and close the .wav file.

attributes

is_active: A boolean indicating whether or not this WaveRecorder is currently recording audio data.

Conference

Conference support is implemented in the sipsimple.conference module. Currently, only audio conferencing is supported.

AudioConference

This class contains the basic implementation for audio conferencing. It acts as a container for AudioStream objects which it will connect in a full mesh, such that all participants can hear all other participants.

methods

__init__(self): Instantiates a new AudioConference which is ready to contain AudioStream objects.

add(self, stream): Add the specified AudioStream object to the conference.

remove(self, stream): Removes the specified AudioStream object from the conference. Raises a ValueError if the stream is not part of the conference.

hold(self): Puts the conference "on hold". This means that the audio device will be disconnected from the conference: all the participants will be able to continue the conference, but the local party will no longer contribute any audio data and will not receive any audio data using the input and output devices respectively. This does not affect the hold state of the streams in any way.

unhold(self): Removes the conference "from hold". This means that the audio device will be reconnected to the conference: all the participants will start to hear the local party and the local party will start to hear all the participants. This does not affect the hold state of the streams in any way.

attributes

bridge: An AudioBridge which this conference uses to connect all audio streams. It can be used by the application to play a wav file using a WavePlayer to all the participants or record the whole conference using a WaveRecorder.

on_hold: A boolean indicating whether or not the conference is "on hold".

streams: The list of streams which are part of this conference. The application must not manipulate this list in any way.

Attachments

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Middleware API

Table of Contents

SIPApplication

methods

attributes

notifications

SIP Sessions

SessionManager

attributes

methods

Session

methods

attributes

notifications

IMediaStream

methods

attributes

notifications

MediaStreamRegistry

methods

MediaStreamRegistrar

AudioStream

methods

attributes

notifications

MSRPStreamBase

methods

attributes

notifications

ChatStream

methods

notifications

FileSelector

methods

attributes

FileTransferStream

methods

notifications

IDesktopSharingHandler

methods

attributes

notifications

InternalVNCViewerHandler

methods

notifications

InternalVNCServerHandler

methods

notifications

ExternalVNCViewerHandler

methods

attributes

ExternalVNCServerHandler

methods

DesktopSharingStream

methods

attributes

Address Resolution

DNS Lookup

methods

notifications

Route

methods

SIP Accounts

AccountManager

methods

notifications

Account

states

attributes

notifications

BonjourAccount

states

attributes

notifications

Audio

IAudioPort

attributes

notifications

AudioDevice