From 6c1504629f6eedbf5df330cbd745091543d4cb2d Mon Sep 17 00:00:00 2001 From: Guido van Rossum Date: Fri, 28 Apr 1995 22:28:39 +0000 Subject: [PATCH] extensive description of what's here --- Demo/pdist/README | 84 ++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 83 insertions(+), 1 deletion(-) diff --git a/Demo/pdist/README b/Demo/pdist/README index 738126dcebe..23120613d15 100644 --- a/Demo/pdist/README +++ b/Demo/pdist/README @@ -1,2 +1,84 @@ +Filesystem, RCS and CVS client and server classes +================================================= + This directory contains various modules and classes that support -remote file system operations +remote file system operations. + +rrcs.py Remote RCS client command line interface +rrcs Script to put in your bin directory + +rcvs.py Remote CVS client command line interface +rcvs Script to put in your bin directory + +sumtree.py Old demo for FSProxy +cmptree.py First FSProxy client (used to sync from the Mac) + +cvslib.py CVS admin files classes (used by rrcs) +rcsclient.py Return an RCSProxyClient instance + (has reasonable default server/port/directory) + +FSProxy.py Filesystem interface classes +RCSProxy.py RCS interface classes + +client.py Client class +server.py Server class + +cmdfw.py CommandFrameWork class + (used by rcvs, should be used by rrcs as well) + + +Client/Server operation +----------------------- + +The Client and Server classes implement a simple-minded RPC protocol, +using Python's pickle module to transfer arguments, return values and +exceptions with the most generality. The Server class is instantiated +with a port number on which it should listen for requests; the Client +class is instantiated with a host name and a port number where it +should connect to. Once a client is connected, a TCP connection is +maintained between client and server. + +The Server class currently handles only one connection at a time; +however it could be rewritten to allow various modes of operations, +using multiple threads or processes or the select() system call as +desired to serve multiple clients simultaneously (when using select(), +still handling one request at a time). This would not require +rewriting of the Client class. It may also be possible to adapt the +code to use UDP instead of TCP, but then both classes will have to be +rewritten (and unless extensive acknowlegements and request serial +numbers are used, the server should handle duplicate requests, so its +semantics should be idempotent -- shrudder). + +Even though the FSProxy and RCSProxy modules define client classes, +the client class is fully generic -- what methods it supports is +determined entirely by the server. The server class, however, must be +derived from. This is generally done as follows: + + from server import Server + from client import Client + + # Define a class that performs the operations locally + class MyClassLocal: + def __init__(self): ... + def _close(self): ... + + # Derive a server class using multiple inheritance + class MyClassServer(MyClassLocal, Server): + def __init__(self, address): + # Must initialize MyClassLocal as well as Server + MyClassLocal.__init__(self) + Server.__init__(self, address) + def _close(self): + Server._close() + MyClassLocal._close() + + # A dummy client class + class MyClassClient(Client): pass + +Note that because MyClassLocal isn't used in the definition of +MyClassClient, it would actually be better to place it in a separate +module so the definition of MyClassLocal isn't executed when we only +instantiate a client. + +The modules client and server should probably be renamed to Client and +Server in order to match the class names.