diff -r ffa851df0825 -r 2fb8b9db1c86 symbian-qemu-0.9.1-12/python-2.6.1/Demo/pdist/README --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/symbian-qemu-0.9.1-12/python-2.6.1/Demo/pdist/README Fri Jul 31 15:01:17 2009 +0100 @@ -0,0 +1,121 @@ +Filesystem, RCS and CVS client and server classes +================================================= + +*** See the security warning at the end of this file! *** + +This directory contains various modules and classes that support +remote file system operations. + +CVS stuff +--------- + +rcvs Script to put in your bin directory +rcvs.py Remote CVS client command line interface + +cvslib.py CVS admin files classes (used by rrcs) +cvslock.py CVS locking algorithms + +RCS stuff +--------- + +rrcs Script to put in your bin directory +rrcs.py Remote RCS client command line interface + +rcsclient.py Return an RCSProxyClient instance + (has reasonable default server/port/directory) + +RCSProxy.py RCS proxy and server classes (on top of rcslib.py) + +rcslib.py Local-only RCS base class (affects stdout & + local work files) + +FSProxy stuff +------------- + +sumtree.py Old demo for FSProxy +cmptree.py First FSProxy client (used to sync from the Mac) +FSProxy.py Filesystem interface classes + +Generic client/server stuff +--------------------------- + +client.py Client class +server.py Server class + +security.py Security mix-in class (not very secure I think) + +Other generic stuff +------------------- + +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. + + +*** Security warning: this version requires that you have a file +$HOME/.python_keyfile at the server and client side containing two +comma- separated numbers. The security system at the moment makes no +guarantees of actuallng being secure -- however it requires that the +key file exists and contains the same numbers at both ends for this to +work. (You can specify an alternative keyfile in $PYTHON_KEYFILE). +Have a look at the Security class in security.py for details; +basically, if the key file contains (x, y), then the security server +class chooses a random number z (the challenge) in the range +10..100000 and the client must be able to produce pow(z, x, y) +(i.e. z**x mod y).