PythonWise: April 2008

Wednesday, April 30, 2008

XML RPC File Server

#!/usr/bin/env python
'''Simple file client/server using XML RPC'''

from SimpleXMLRPCServer import SimpleXMLRPCServer
from xmlrpclib import ServerProxy, Error as XMLRPCError
import socket

def get_file(filename):
  fo = open(filename, "rb")
  try: # When will "with" be here?
      return fo.read()
  finally:
      fo.close()

def main(argv=None):
  if argv is None:
      import sys
      argv = sys.argv

  default_port = "3030"
  from optparse import OptionParser

  parser = OptionParser("usage: %prog [options] [[HOST:]PORT]")
  parser.add_option("--get", help="get file", dest="filename",
          action="store", default="")

  opts, args = parser.parse_args(argv[1:])
  if len(args) not in (0, 1):
      parser.error("wrong number of arguments") # Will exit

  if args:
      port = args[0]
  else:
      port = default_port

  if ":" in port:
      host, port = port.split(":")
  else:
      host = "localhost"

  try:
      port = int(port)
  except ValueError:
      raise SystemExit("error: bad port - %s" % port)

  if opts.filename:
      try:
          proxy = ServerProxy("http://%s:%s" % (host, port))
          print proxy.get_file(opts.filename)
          raise SystemExit
      except XMLRPCError, e:
          error = "error: can't get %s (%s)" % (opts.filename, e.faultString)
          raise SystemExit(error)
      except socket.error, e:
          raise SystemExit("error: can't connect (%s)" % e)

  server = SimpleXMLRPCServer(("localhost", port))
  server.register_function(get_file)
  print "Serving files on port %d" % port
  server.serve_forever()

if __name__ == "__main__":
  main()

This is a huge security hole, use at your own risk.

Friday, April 18, 2008

web-install


#!/bin/bash
# Do the `./configure && make && sudo make install` dance, given a download URL

if [ $# -ne 1 ]; then
    echo "usage: `basename $0` URL"
    exit 1
fi

set -e  # Fail on errors

url=$1

wget --no-check-certificate $url
archive=`basename $url`

if echo $archive | grep -q .tar.bz2; then
    tar -xjf $archive
else
    tar -xzf $archive
fi

cd ${archive/.tar*}

if [ -f setup.py ]; then
    sudo python setup.py install
else
    ./configure && make && sudo make install
fi

cd ..

Tuesday, April 15, 2008

Some sites (such as Google), gives you a "trampoline" URL so they can register what you have clicked on. I find it highly annoying since you can't tell where you are going just by hovering above the URL and you can't "copy link location" to a document.

The problem is that these people are just lazy:

<html>
   <body>
       <a href="http://pythonwise.blogspot.com"
           onclick="jump(this, 1);">Pythonwise</a> knows.
   </body>
   <script src="jquery.js"></script>
   <script>
       function jump(url, value)
       {
           $.post("jump.cgi", {
               url: url,
               value: value
           });

           return true;
       }
   </script>
</html>

Notes:

Using jQuery
"value" can be anything you want to identify this specific click. I'd use a UUID and some table for registering who is the user, what is the url, the time ...

Wednesday, April 09, 2008

num_checkins


#!/bin/bash
# How many checking I did today?
# Without arguments will default to current directory

svn log -r"{`date +%Y%m%d`}:HEAD" $1 | grep "| $USER |" | wc -l

Thursday, April 03, 2008

FeedMe - A simple web-based RSS reader

A simple web-based RSS reader in less than 100 lines of code.

Using feedparser, jQuery and plain old CGI.

index.html


<html>
 <head>
     <title>FeedMe - A Minimal Web Based RSS Reader</title>
     <link rel="stylesheet" type="text/css" href="feedme.css" />
     <link rel="shortcut icon" href="feedme.ico" />
     <style>
         a {
             text-decoration: none;
         }
         a:hover {
             background-color: silver;
         }
         div.summary {
             display: none;
             position: absolute;
             background: gray;
             width: 70%;
             font 18px monospace;
             border: 1px solid black;
         }
     </style>
 </head>
 <body>
     <h2>FeedMe - A Minimal Web Based RSS Reader</h2>
     <div>
         Feed URL: <input type="text" size="80" id="feed_url"/>
         <button onclick="refresh_feed();">Load</button>
     </div>
     <hr />
     <div id="items">
     <div>
 </body>
 <script src="jquery.js"></script>
 <script>
     function refresh_feed() {
         var url = $.trim($("#feed_url").val());
         if ("" == url) {
             return;
         }

         $("#items").load("feed.cgi", {"url" : url});
         /* Update every minute */
         setTimeout("refresh_feed();", 1000 * 60);
     }
 </script>
</html>

feed.cgi


#!/usr/bin/env python

import feedparser
from cgi import FieldStorage, escape
from time import ctime

ENTRY_TEMPLATE = '''
<a href="%(link)s"
 onmouseover="$('#%(eid)s').show();"
 onmouseout="$('#%(eid)s').hide();"
 target="_new"
>
%(title)s
</a> <br />
<div class="summary" id="%(eid)s">
%(summary)s
</div>
'''

def main():
 print "Content-type: text/html\n"

 form = FieldStorage()
 url = form.getvalue("url", "")
 if not url:
     raise SystemExit("error: not url given")

 feed = feedparser.parse(url)
 for enum, entry in enumerate(feed.entries):
     entry.eid = "entry%d" % enum
     try:
         html = ENTRY_TEMPLATE % entry
         print html
     except Exception, e:
         # FIXME: Log errors
         pass

 print "<br />%s" % ctime()

if __name__ == "__main__":
 main()

How it works:

The JavaScript script call loads the output of feed.cgi to the items div
feed.cgi reads the RSS feed from the given URL and output an HTML fragment
Hovering over a title will show the entry summary
setTimeout makes sure we refresh the view every minute

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