Channels Server

Implements the Django Message Broker Server.

class django_message_broker.server.channels_server.ChannelsServer(ip_address: str = '127.0.0.1', port: int = 5556)

Message server for Django Channels.

Implements a network message server for Django channels using zero message queue (ZMQ) to support communication between channels registered within different processes.

The server opens two sequential ports:

Data port (base port, default=5556): Transmission of data messages between the client and server.
Signalling port (base port + 1, default=5557): Transmission of signalling messages between the client and server.

class DataCommands: Create registry of data commands using decorators.

class SignallingCommands: Create registry of signalling commands using decorators.

start() → None

Start the channels server.

Raises: ChannelsServerError – If the server cannot be started.

stop() → None: Stop the channels server.

_receive_data(multipart_message: Union[_asyncio.Future, List]) → None

Callback raised when a message is received on the data port. Parses the message to identify the relevant command and dispatches the messages to the relevant command handler.

If the “ack” property is set then the server will send a response to the client. There are three potential responses:

COMPLETE: The command completed successfully.
EXCEPTION: An exception occurred in the server.
COMMAND SPECIFIC: A specific response to the command generated by the server.

Parameters: multipart_message (Union[Future, List]) – Multipart message received on data port.

_subscribe(message: django_message_broker.server.data_message.DataMessage) → None

Command handler for SUBCHANX: Subscribe to a channel.

Registers an endpoint as a subscriber to a channel. If the channel doesn’t exist then it creates a new channel.

Parameters: message (DataMessage) – Message received requesting subscription to the channel.

_unsubscribe(message: django_message_broker.server.data_message.DataMessage) → None

Command handler for USUBCHAN: Unsubscribe to a channel.

Removes an endpoint from a channel.

Parameters: message (DataMessage) – Message received requesting subscription to the channel.

_send_to_channel(message: django_message_broker.server.data_message.DataMessage) → None

Command handler for SENDCHAN: Send message to a channel.

Creates a new queue if one does not exist. Adds the message to the queue.

If the “ttl” property is set on the message then set the expiry time of the message.

Parameters: message (DataMessage) – Received data message.

_send_to_group(message: django_message_broker.server.data_message.DataMessage) → None

Command handler for SENDGRPX: Send message to a group.

Sends a message to a group of channels. The method creates a quick copy of the data message and pushes it to each channel. The shallow copy share the body of the message between all copies to reduce encoding/decoding times and memory utilisation.

Parameters: message (DataMessage) – Received data message.

_receive_signalling(multipart_message: Union[_asyncio.Future, List]) → None

Callback raised when a message is received on the signalling port. Parses the message to identify the relevant command and dispatches the messages to the relevant command handler.

If the “ack” property is set then the server will send a response to the client. There are three potential responses:

COMPLETE: The command completed successfully.
EXCEPTION: An exception occurred in the server.
COMMAND SPECIFIC: A specific response to the command generated by the server.

Parameters

multipart_message (Union[Future, List]) – Multipart message received on data port.

Raises

ImportError – Error raised if the multitpart message cannot be parsed to a valid data message.
MessageCommandUnknown – The command in the message is unknown.

_group_add(message: django_message_broker.server.signalling_message.SignallingMessage) → None