HI Thanks for this very detailed explanation. I would like to explain what I have understood with respect to XML-RPC I have a client side application in VB.NET sending XML-RPC request on a TCP connection The Linux Machine on which Zope-2.5.1 is installed and running on port 8080 also has an XML-RPC server running on port 9092 on the machine (xmlrpclib from www.pythonware.com ) But I have understood that Zope understands XML-RPC requests without a Server running on the machine. That means even if I dont have an XML-RPC server running on the Linux machine it is ok as long as the request is to the Zope Server. SInce I am sending requests to Python Scripts written in Zope and the Zope server understands XML-RPC requests I dont need a separate XML-RPC Server for this. But if I was trying to access any other python files outside Zope then I would need to have an XML_RPC server running tp listen to the requests. Also since my requests to Zope are coming over the TCP it is keeping a track of the server and Client details. So the Server knows from which IP the request has come. The Problem arises because the Proxy Server I.P. from my firm is the I.P that the server will get with a request. But within the LAN there are a number of machines sending requests to the Remote Zope Server simultaneously. When the Zope Server sends response it will send the reponses back to the coprrect I.P. which is the Proxy I.P. But then requests from each machine in the LAN will need to be tracked by the Proxy with respect to say some unique Identifying Variable that I send with each request and response. I don't know how clearly I have been able to explain what I am trying to do here. I have been able to send and receive request and responses based on a unique Id generated when the User Logs in to the Application. This Id is generated in Zope and sent back along with the response after validating the USer for correct Login. Now everytime a Request or response is sent till the time that the User doesnot Log out the Same process of sending and Receiving requests and responses along with the Unoique Id is how I am doing it. Could anyone think of a better Idea as to how to solve this problem in a more defined Manner? All help received is GREATLY appreciated. Thanks and Best regards John Kunchandy ============================================================================ ======= jwsacksteder@ramprecision.com <jwsacksteder@ramprecision.com> Think about it like this:
XML-RPC works exactly like web page requests. Normally a browser contacts
a
web server with a tcp connection and sends a http GET command. The server then responds with a HTML document ON THE SAME TCP CONNECTION.
With XML-RPC you are sending a RPC request as a formatted XML document to a server over the HTTP transport protocol and the server responds by sending the results of that RPC request back as formatted XML.
In this situation, you are bound by the limitations of that single tcp connection. Most notably, idle timeouts. If you have a request that takes 15 minutes to process, the tcp connection will have died long before the request comes back. XML-RPC does not specifically address persistant connections like this. SOAP is an extension of XML-RPC that adds support for this, though some would say that goes against the principles of XML-RPC.
Most likely, what you want is to have XML-RPC servers/listeners on the clients as well. What you have then is a peer-to-peer messaging network. A client can send a XML-RPC request to a server, along with its address, name and cryptographic key and when the response is ready, the server will initate a NEW XML-RPC message and send it back to the originator. If you use a public-key crypto system, you are protected from sending data to the wrong client if the ip address changes.
If you had a application where a server needed to notify clients when certain things happened, you would have to make the clients register themselves somehow with the server when they first started. Otherwise the server would never know where the clients are.
It might be worth your time to run through the XML-RPC transaction by hand to see what is happening. Just telnet to whatever port your server is listening(ex. telnet 192.168.0.1 80) on and type a simple XML-PRC request and see what comes back in the terminal window. ============================================================================ ======== I am working on an VB.NET client side application that sends requests in XML-RPC to a Zope server running on Linux(Mandrake 8.0) The request calls a python script and it returns a String . But when there are multiple requests (i.e; from different machines on the network) .the XmlRPc Server throws an XML RPC Fault Error. The 2.6 "xmlrpc.py" file provides support for a traceback. It will tell you about the location and cause of the exception.
I think, I posted a patch with similar functionality for Zope 2.5.1. Search the archives...
Does XML-RPC Server maintain a record of the IP address of the client machine that sent the request so that it can respond back to the same machine? No, it does not.
TCP/IP connections (and therefore HTTP and XML-RPC connections) are bi-directional. You can read and write to them. TCP/IP transparently handles the transport. (Of course, TCP/IP knows the IP address of both ends of the connection). Dieter
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