NAME

Tangence::Stream - base class for Tangence stream-handling mixins

DESCRIPTION

This module provides a base for Tangence::Client and Tangence::Server. It is not intended to be used directly by Tangence implementation code.

It provides the basic layer of message serialisation, deserialisation, and dispatching to methods that would handle the messages. Higher level classes are used to wrap this functionallity, and provide implementations of methods to handle the messages received.

When a message is received, it will be passed to a method whose name depends on the type of message received. The name will be handle_request_, followed by the name of the message type, in uppercase; for example handle_request_CALL.

REQUIRED METHODS

The following methods are required to be implemented by some class using this mixin.

$stream->tangence_write( $data )

Write bytes of data to the connected peer. $data will be a plain perl string.

$stream->handle_request_$TYPE( $token, $message )

Invoked on receipt of a given message type. $token will be some opaque perl scalar value, and $message will be an instance of Tangence::Message.

The value of the token has no particular meaning, other than to be passed to the respond method.

PROVIDED METHODS

The following methods are provided by this mixin.

$stream->tangence_closed

Informs the object that the underlying connection has now been closed, and any attachments to Tangence::Object or Tangence::ObjectProxy instances should now be dropped.

$stream->tangence_readfrom( $buffer )

Informs the object that more data has been read from the underlying connection stream. Whole messages will be removed from the beginning of the $buffer, which should be passed as a direct scalar (because it will be modified). This method will invoke the required handle_request_* methods. Any bytes remaining that form the start of a partial message will be left in the buffer.

$stream->request( %args )

Serialises a message object to pass to the tangence_write method, then enqueues a response handler to be invoked when a reply arrives. Takes the following named arguments:

request => Tangence::Message

The message body

on_response => CODE

CODE reference to the callback to be invoked when a response to the message is received. It will be passed the response message:

 $on_response->( $message )

$stream->respond( $token, $message )

Serialises a message object to be sent to the tangence_write method. The $token value that was passed to the handle_request_ method ensures that it is sent at the correct position in the stream, to allow the peer to pair it with the corresponding request.

AUTHOR

Paul Evans <leonerd@leonerd.org.uk>