Kamaelia docs : Kamaelia.Internet.ConnectedSocketAdapter

Kamaelia.Internet.ConnectedSocketAdapter

component ConnectedSocketAdapter

Talking to network sockets

Talking to network sockets

A Connected Socket Adapter (CSA) component talks to a network server socket. Data is sent to and received from the socket via this component's inboxes and outboxes. A CSA is effectively a wrapper for a socket.

Most components should not need to create CSAs themselves. Instead, use components such as TCPClient to make an outgoing connection, or TCPServer or SimpleServer to be a server that responds to incoming connections.

Example Usage

See source code for TCPClient to see how Connected Socket Adapters can be used.

How does it work?

A CSA is usually created either by a component such as TCPClient that wants to establish a connection to a server; or by a primary listener socket - a component acting as a server - listening for incoming connections from clients.

The socket should be set up and passed to the constructor to make the CSA.

Incoming data, read by the CSA, is sent out of its "outbox" outbox as strings containing the received binary data. Send data by sending it, as strings, to the "inbox" outbox.

The CSA expects to be wired to a component that will notify it when new data has arrived at its socket (by sending an Axon.Ipc.status message to its "ReadReady" inbox. This is to allow the CSA to sleep rather than busy-wait or blocking when waiting for new data to arrive. Typically this is the Selector component.

This component will terminate (and close its socket) if it receives a producerFinished or shutdownMicroprocess message on its "control" inbox.

When this component terminates, it sends a socketShutdown(socket) message out of its "CreatorFeedback" outbox and a shutdownCSA((selfCSA,self.socket)) message out of its "signal" outbox.

The message sent to "CreatorFeedback" is to notify the original creator that the socket is now closed and that this component should be unwired.

The message sent to the "signal" outbox serves to notify any other component involved - such as the one feeding notifications to the "ReadReady" inbox (eg. the Selector component).

Kamaelia.Internet.ConnectedSocketAdapter.ConnectedSocketAdapter

class ConnectedSocketAdapter(Axon.Component.component)

ConnectedSocketAdapter(socket) -> new CSA component wrapping specified socket

Component for communicating with a socket. Send to its "inbox" inbox to send data, and receive data from its "outbox" outbox.

"ReadReady" inbox must be wired to something that will notify it when new data has arrived at the socket.

Inboxes

control : Shutdown on producerFinished message (incoming & outgoing data is flushed first)
ReadReady : Notify this CSA that there is incoming data ready on the socket
makessl : Notify this CSA that the socket should be wrapped into SSL
inbox : Data for this CSA to send through the socket (Axon.Ipc.status message)
SendReady : Notify this CSA that the socket is ready to send

Outboxes

outbox : Data received from the socket
CreatorFeedback : Expected to be connected to some form of signal input on the CSA's creator. Signals socketShutdown (this socket has closed)
sslready : Notifies components that the socket is now wrapped into SSL
signal : Signals shutdownCSA (this CSA is shutting down)
_selectorSignal : For communication to the selector

Methods defined here

Warning!

You should be using the inbox/outbox interface, not these methods (except construction). This documentation is designed as a roadmap as to their functionalilty for maintainers and new component developers.

init(self, listensocket, selectorService[, crashOnBadDataToSend][, noisyErrors])

x.__init__(...) initializes x; see x.__class__.__doc__ for signature

_saferecv(self, sock[, size])

Internal only function, used for recieving data, and handling EAGAIN style retry scenarios gracefully

_safesend(self, sock, data)

Internal only function, used for sending data, and handling EAGAIN style retry scenarios gracefully

canDoSomething(self)

checkSocketStatus(self)

flushSendQueue(self)

handleControl(self)

Check for producerFinished message and shutdown in response

handleReceive(self)

main(self)

passOnShutdown(self)

stop(self)

Feedback

Got a problem with the documentation? Something unclear that could be clearer? Want to help improve it? Constructive criticism is very welcome - especially if you can suggest a better rewording!

Please leave you feedback here in reply to the documentation thread in the Kamaelia blog.

-- Automatic documentation generator, 05 Jun 2009 at 03:01:38 UTC/GMT

Kamaelia is an open source project originated from and guided by BBC Research. For more information browse the site or get in contact.

This is an ongoing community based development site. As a result the contents of this page is the opinions of the contributors of the pages involved not the organisations involved. Specificially, this page may contain personal views which are not the views of the BBC. (the site is powered by a wiki engine)