streamrpc - XML-RPC and JSON-RPC over raw streams

streamrpc is a Python module that allows setting up RPC communication over a pipe or other raw data stream - any object pair that supports a read and write method respectively.

The main design goals:

• Require as little as possible of the transport implementation (i.e. read, write and optionally close and flush).
• Create no "meta-protocol" (such as HTTP for XML-RPC) around it.
• Otherwise follow the XML-RPC and JSON-RPC specifications.

Major use cases:

• Efficient RPC between subprocesses written in different languages on different architectures.
• RPC over SSH.

Currently not supported:

• Full duplex RPC (i.e. both ends of the pipe can initiate requests). This would be interesting and useful but is not currently supported.
• Asynchronous operation. This is not currently supported, but planned.

Usage

Use case: Create server and client subprocess

To create a server, create the Server object:

import streamrpc
import subprocess

process = subprocess.Popen("ssh xxx python client.py",
            stdin=subprocess.PIPE,
            stdout=subprocess.PIPE) 
            # Run client, i.e. from SSH

rpc = streamrpc.Server(process=process)

def echo(val):
	print val
	return val
rpc.register_function(echo)	
rpc.process_one()

Note that there is no need to specify whether the server is an XML-RPC or JSON-RPC server: it will detect this from the first incoming request. If this is not desired, the XmlServer and JsonServer classes also exist.

The client would then be implemented as:

import streamrpc

client = streamrpc.JsonClient()
print >>sys.stderr, client.echo("Hello")