Find Module Version

Quick script to check which version of Python module is installed.

#!/usr/bin/env python
'''Find python module version'''

__author__ = "Miki Tebeka <miki.tebeka@gmail.com>"

def valueof(v):
    if callable(v):
        try:
            return v()
        except Exception:
            return None
    return v

def load_module(module_name):
    module = __import__(module_name)

    # __import__("a.b") will give us a
    if ("." in module_name):
        names = module_name.split(".")[1:]
        while names:
            name = names.pop(0)
            module = getattr(module, name)

    return module

def find_module_version(module_name):
    module = load_module(module_name)
    attrs = set(dir(module))

    for known in ("__version__", "version", "version_string"):
        if known in attrs:
            v = valueof(getattr(module, known))
            if v:
                return v

    for attr in attrs:
        if "version" in attr.lower():
            v = getattr(module, attr)
            if not v:
                continue
            v = valueof(v)
            if v:
                return v

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

    from optparse import OptionParser

    parser = OptionParser("usage: %prog MODULE_NAME")

    opts, args = parser.parse_args(argv[1:])
    if len(args) != 1:
        parser.error("wrong number of arguments") # Will exit

    module_name = args[0]

    try:
        version = find_module_version(module_name)
    except ImportError, e:
        raise SystemExit("error: can't import %s (%s)" % (module_name, e))

    if version:
        print version
    else:
        raise SystemExit("error: can't find version for %s" % module_name)

if __name__ == "__main__":
    main()

Which build utility to run?

I have the following as a script called "mk" and set in my .vimrc

set makeprg=mk

#!/bin/bash
# Guess which make utility to use

# Miki Tebeka <miki.tebeka@gmail.com>

makecmd=""
if [ -f SConstruct ]; then
    makecmd="scons -Q -D"
elif [ -f build.xml ]; then
    makecmd="ant"
elif [ -f Makefile ]; then
    makecmd="make"
elif [ -f makefile ]; then
    makecmd="make"
elif [ "$OSTYPE" == "WINNT" ]; then
    proj=`ls *.dsp 2>/dev/null`
    if [ -f $proj ]; then
        makecmd="msdev $proj /MAKE"
    fi
fi

if [ -z "$makecmd" ]; then
    echo "can't find project file"
    exit 1
fi

$makecmd $@

Moved to bitbucket

All(?) the code from this blog is now at BitBucket

imapclean

#!/usr/bin/env python
'''Clean your IMAP inbox

Copy all message to "Archive" and delete them from Inbox
'''

__author__ = "Miki Tebeka <miki.tebeka@gmail.com>"

from imaplib import IMAP4
import logging as log

def move_messages(server, user, passwd, purge=0):
    imap = IMAP4(server)
    imap.login(user, passwd)
    imap.select()
    messages = imap.search(None, "ALL")[1][0].split()
    for msg_id in messages:
        flags = imap.fetch(msg_id, "(FLAGS)")[1][0]
        if not flags.startswith(msg_id):
            log.error("bad reply for %s flags - %s" % (msg_id, flags))
            continue
        if "Deleted" in flags:
            log.info("skipping %s - already deleted" % msg_id)
            continue
        log.info("deleting %s" % msg_id)
        imap.copy(msg_id, "Archive")
        imap.store(msg_id, "+FLAGS", "\\Deleted")

    if purge:
        log.info("purging deleted messages")
        imap.expunge()
    log.info("logging out")
    imap.close()
    imap.logout()

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

    from optparse import OptionParser
    from getpass import getpass, getuser

    parser = OptionParser("usage: %prog")
    parser.add_option("-p", "--purge", help="purge deleted messages",
        action="store_true", default=0, dest="purge")
    parser.add_option("-v", "--verbose", help="be verbose",
                      dest="verbose", action="store_true", default=0)
    parser.add_option("--server", help="imap server",
            default="localhost", dest="server")
    parser.add_option("--user", help="IMAP user name",
            dest="user", default="")
    parser.add_option("--passwd", help="IMAP password",
            dest="passwd", default="")

    opts, args = parser.parse_args(argv[1:])
    if args:
        parser.error("wrong number of arguments") # Will exit

    level = log.DEBUG if opts.verbose else log.ERROR
    log.basicConfig(format="%(levelname)s: %(message)s",
                        level=level)

    opts.user = opts.user or getuser()
    opts.passwd = opts.passwd or getpass()

    try:
        move_messages(opts.server, opts.user, opts.passwd, opts.purge)
    except Exception, e:
        if opts.verbose:
            log.exception(e)
        else:
            log.error(e)
        raise SystemExit(1)

if __name__ == "__main__":
    main()

Yeah, the pygments experiment worked.

crashlog

Get email notification whenever your program crashes.

The Code You Don't Write

Act without doing, work without effort.
Think of the small as large and the few as many.
Confront the difficult while it is still easy;
accomplish the great task by a series of small steps.
    - Lao-Tze

Sometimes, the code you don't write is more important than the one you write.
Whenever I start on a new task, my first question is "how can I do this without coding?".

Here's a small (true) exmaple:

We had a problem that serving files on an NFS mounted volume was slow for the first request and them it was good. Probably the mount went "stale" after a while.

First option of learning the inner working of NFS mounts was dropped immediately - you can never know how much time this tinkering will take and if it'll work eventually.

So I decided to keep the NFS mount "warm" by periodically accessing it.

First Version:

from time import sleep
from os import listdir

while 1:
    listdir("/path/to/nfs")
    sleep(10 * 60 * 60)

and in crontab

@reboot /usr/bin/python /path/to/script.py

Then I thought - "cron", and second version came:

from os import listdir

listdir("/path/to/nfs")</code></pre>

and in crontab:

*/10 * * * * /usr/bin/python /path/to/script.py

And then last version (just crontab):

*/10 * * * * /bin/ls /path/to/nfs

So down from 6 LOC to 3 LOC to 1 LOC - that's what I call produtivity :)

Where is Miki?

A little CGI script that show where I am (gets data from my google calendar).

Using Google Data Python API

#!/usr/bin/env python
'''Where where am I? (data from Google calendar)

Get gdata from http://code.google.com/p/gdata-python-client/
'''

__author__ = "Miki Tebeka <miki.tebeka@gmail.com>"

import gdata.calendar.service as cal_service
from time import localtime, strptime, strftime, mktime, timezone

DAY = 24 * 60 * 60

def caltime_to_local(caltime):
    # 2008-11-07T23:30:00.000+02:00
    t = mktime(strptime(caltime[:16], "%Y-%m-%dT%H:%M"))
    tz_h, tz_m = map(int, caltime[-5:].split(":"))
    cal_tz = (tz_h * 60 * 60) + (tz_m * 60)
    if caltime[-6] == "-":
        cal_tz = -cal_tz

    # See timezone documentation, the sign is reversed
    diff = -timezone - cal_tz 

    return localtime(t + diff)

def iter_meetings():
    client = cal_service.CalendarService()
    client.email = "your-google-user-name"
    client.password = "your-google-password"
    client.source = "Where-is-Miki"
    client.ProgrammaticLogin()

    query = cal_service.CalendarEventQuery("default", "private", "full")
    query.start_min = strftime("%Y-%m-%d")
    tomorrow = localtime(mktime(localtime()) + DAY)
    query.start_max = strftime("%Y-%m-%d", tomorrow)
    feed = client.CalendarQuery(query)
    for event in feed.entry:
        title = event.title.text
        when = event.when[0]
        start = caltime_to_local(when.start_time)
        end = caltime_to_local(when.end_time)

        yield title, start, end

def find_meeting(meetings, now):
    for title, start, end in meetings:
        print title, start, end
        if start <= now <= end:
            return title, end

    return None, None

def meetings_html(meetings):
    if not meetings:
        return "No meetings today"

    trs = []
    tr = "<tr><td>%s</td><td>%s</td><td>%s</td></tr>"
    for title, start, end in meetings:
        start = strftime("%H:%M", start)
        end = strftime("%H:%M", end)
        trs.append(tr % (title, start, end))

    return "Today's meetings: <table border='1'>" + \
           "<tr><th>Title</th><th>Start</th><th>End</th></tr>" + \
            "\n".join(trs) + \
            "</table>"

HTML = '''
<html>
    <head>
        <title>Where is Miki?</title>
        <style>
            body, td, th {
                font-family: Monospace;
                font-size: 22px;
            }
        </style>
    </head>
    <body>
        <h1>Where is Miki?</h1>
        <p>
            Seems that he is <b>%s</b>.
        </p>
        <p>
            %s
        </p>
    </body>
</html>
'''

if __name__ == "__main__":
    import cgitb; cgitb.enable()
    from operator import itemgetter

    days = ["Mon","Tue","Wed", "Thu", "Fri", "Sat", "Sun"]
    now = localtime()

    day = days[now.tm_wday]
    meetings = sorted(iter_meetings(), key=itemgetter(-1))

    # Yeah, yeah - I get in early
    if (now.tm_hour < 6) or (now.tm_hour > 17):
        where = "at home"
    elif day in ["Sat", "Sun"]:
        where = "at home"
    else:
        title, end = find_meeting(now, meetings)
        if end:
            where = "meeting %s (until %s)" % (title, strftime("%H:%M", end))
        else:
            where = "at work"

    print "Content-Type: text/html\n"
    print HTML % (where, meetings_html(meetings))

Document With Examples

I've found out that a lot of times when I have a parsing code, it's best to document the methods with examples of the input.

A small example:

#!/usr/bin/env python
'''Simple script showing how to document with examples'''

__author__ = "Miki Tebeka <miki.tebeka@gmail.com>"

import re

# HTTP/1.1 200 OK
# HTTP/1.1 301 Moved Permanently
def http_code(line):
    return line.split()[1]

if __name__ == "__main__":
    print http_code("HTTP/1.1 301 Moved Permanently")

JavaScript sound player

It's very easy to connect Adobe FLEX to JavaScript.

We'll create a simple sound player that exposes two functions: play and stop. It'll also call the JavaScript function on_play_complete when the current sound has finished playing.

soundplayer.mxml

Compile with mxmlc soundplayer.mxml

soundplayer.html

"Disabling" an image

Sometimes you want to mark a button image as "disabled". The usual method is to have two images and display the "disabled" state image when disabled.

However you can use the image opacity the mark is as disabled as well:

<html>
    <head>
        <title>Dimmer</title>
        <style>
            .disabled {
                filter: alpha(opacity=50);
                -moz-opacity: 0.50;
                opacity: 0.50;
            }
        </style>
    </head>
    <body>
        <center>
            <p>Show how to "dim" an image, marking it disabled</p>
            <img src="image.png" id="image" /> <br />
            <button onclick="disable();">Disable</button>
            <button onclick="enable();">Enable</button>
        </center>
    </body>
    <script src="jquery.js"></script>
    <script>
        function disable() {
            $('#image').addClass('disabled');
        }

        function enable() {
            $('#image').removeClass('disabled');
        }
    </script>
</html>

Destktop Web Application

It's very easy have the browser window as your user interface, even on desktop applications.

Below is a small phone book demo.

General Design:

• Have a web server serve the main search page
• I'm using BaseHTTPServer but you can use any other framework
  
• Run an AJAX query and display the results
• I'm using jQuery
• fork the server so the program will return
  

webphone.py (AKA the web server)

index.html (AKA the GUI)

pymodver

Which version of module do I have?

#!/usr/bin/env python
'''Find python module version'''

__author__ = "Miki Tebeka <miki.tebeka@gmail.com>"

def valueof(v):
    if callable(v):
        try:
            return v()
        except Exception:
            return None
    return v

def load_module(module_name):
    module = __import__(module_name)

    # __import__("a.b") will give us a
    if ("." in module_name):
        names = module_name.split(".")[1:]
        while names:
            name = names.pop(0)
            module = getattr(module, name)

    return module

def find_module_version(module_name):
    module = load_module(module_name)
    attrs = set(dir(module))

    for known in ("__version__", "version"):
        if known in attrs:
            v = valueof(getattr(module, known))
            if v:
                return v

    for attr in attrs:
        if "version" in attr.lower():
            v = getattr(module, attr)
            if not v:
                continue
            v = valueof(v)
            if v:
                return v

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

    from optparse import OptionParser

    parser = OptionParser("usage: %prog MODULE_NAME")

    opts, args = parser.parse_args(argv[1:])
    if len(args) != 1:
        parser.error("wrong number of arguments") # Will exit

    module_name = args[0]

    try:
        version = find_module_version(module_name)
    except ImportError, e:
        raise SystemExit("error: can't import %s (%s)" % (module_name, e))

    if version:
        print version
    else:
        raise SystemExit("error: can't find version for %s" % module_name)

if __name__ == "__main__":
    main()

Exit Gracefully

When your program is terminated by a signal, the atexit handlers are not called.

A short solution:

"unpack" updated

Updated the code to unpack and added view functionality to it.

putclip

A "cross platform" command line utility to place things in the clipboard.
(On linux uses xsel)

#!/usr/bin/env python
'''Place stuff in clipboard - multi platform'''

__author__ = "Miki Tebeka <miki.tebeka@gmail.com>"

from os import popen
from sys import platform

COMMDANDS = { # platform -> command
    "darwin" : "pbcopy",
    "linux2" : "xsel -i",
    "cygwin" : "/bin/putclip",
}

def putclip(text):
    command = COMMDANDS[platform]
    popen(command, "w").write(text)

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

    from optparse import OptionParser
    from sys import stdin

    parser = OptionParser("%prog [PATH]")

    opts, args = parser.parse_args(argv[1:])

    if len(args) not in (0, 1):
        parser.error("wrong number of arguments") # Will exit

    if platform not in COMMDANDS:
        message = "error: don't know how to handle clipboard on %s" % platform
        raise SystemExit(message)

    if (not args) or (args[0] == "-"):
        info = stdin
    else:
        try:
            infile = args[0]
            info = open(infile)
        except IOError, e:
            raise SystemExit("error: can't open %s - %s" % (infile, e))

    try:
        putclip(info.read())
    except OSError, e:
        raise SystemExit("error: %s" % e)

if __name__ == "__main__":
    main()

flatten

#!/usr/bin/env python

__author__ = "Miki Tebeka <miki.tebeka@gmail.com>"

def flatten(items):
    '''Flatten a nested list.

    >>> a = [[1], 2, [[[3]], 4]]
    >>> list(flatten(a))
    [1, 2, 3, 4]
    >>>
    '''
    for item in items:
        if getattr(item, "__iter__", None):
            for subitem in flatten(item):
                yield subitem
        else:
            yield item

if __name__ == "__main__":
    from doctest import testmod
    testmod()

pipe

printobj

'''Quick and dirty object "repr"'''

__author__ = "Miki Tebeka "
# FIXME: Find how to make doctest play with "regular" class definition

def printobj(obj):
    '''
    Quick and dirty object "repr"

    >>> class Point: pass
    >>> p = Point()
    >>> p.x, p.y = 1, 2
    >>> printobj(p)
    ('y', 2)
    ('x', 1)
    >>>
    '''
    print "\n".join(map(str, obj.__dict__.items()))

if __name__ == "__main__":
    from doctest import testmod
    testmod()

CGI trampoline for cross site AJAX

Most (all?) browsers won't let you do cross site AJAX calls.

One solution is JSONP (which is supported by jQuery). However not all servers support it.

The other solution is to create a "trampoline" in your site that returns the data from the remote site:

whichscm

#!/usr/bin/env python
'''Find under which SCM directory is'''

__author__ = "Miki Tebeka <miki.tebeka@gmail.com>"

from os import sep
from os.path import join, isdir, abspath
from itertools import ifilter, imap

def updirs(path):
    parts = path.split(sep)
    if not parts[0]:
        parts[0] = sep # FIXME: Windows
    while parts:
        yield join(*parts)
        parts.pop()

def scmdirs(path, scms):
    for scmext in scms:
        yield join(path, scmext)

def scm(dirname):
    return dirname[-3:].lower()

def scms(path, scms):
    return imap(scm, ifilter(isdir, scmdirs(path, scms)))


def whichscm(path):
    path = abspath(path)

    for scm in scms(path, (".svn", "CVS")):
        return scm

    scmdirs = (".bzr", ".hg", ".git")
    for dirname in updirs(path):
        for scm in scms(dirname, (".bzr", ".hg", ".git")):
            return scm

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

    from optparse import OptionParser

    parser = OptionParser("usage: %prog [DIRNAME]")

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

    dirname = args[0] if args else "."
    if not isdir(dirname):
        raise SystemExit("error: %s is not a directory" % dirname)

    scm = whichscm(dirname)
    if not scm:
        raise SystemExit("error: can't find scm for %s" % dirname)

    print scm

if __name__ == "__main__":
    main()