devhands

Migrating and syncing samba users

Aleksandr Tsertkov — Mon, 15 Feb 2010 12:44:35 +0000

Samba maintains it’s own user and password database. If you want to synchronize samba users with system users pam_smbpass will to the trick.

Debian/Ubuntu:

sudo apt-get install libpam-smbpass

This package installs pam_smbpass.so and modifies pam.d common-auth and common-password scripts to keep system and samba users in sync.

JavaScript is the language of our future… on the backend!

Aleksandr Tsertkov — Tue, 02 Feb 2010 16:02:50 +0000

Check out this presentation about successful use of comet server based on node.js in highly scalable realtime web application.

Audio Podcast: Unlearn Your MBA

Aleksandr Tsertkov — Tue, 02 Feb 2010 09:56:22 +0000

A very very interesting audio podcast from David Heineimeier Hansson, the creator of Ruby on Rails about his IT business approach and why you should unlearn what you have study in universities.

PHP preg_replace URL

Aleksandr Tsertkov — Mon, 01 Feb 2010 08:59:33 +0000

To search for urls and convert them into html links you may use preg_replace() in PHP. Though writing regular expression might be not very easy. Here is an example of regular expression which will catch and replace urls which may be:

in the beginning of string,
in the end of string,
configurable prefix/suffix delimiter,
with configurable scheme.


 
// configurable delimiters and schemes
$delimiters = '\\s"\\.\',';
$schemes = 'https?|ftps?';
 
$pattern = sprintf('#(^|[%s])((?:%s)://\\S+[^%1$s])([%1$s]?)#i', $delimiters, $schemes);
$replacement = '$1$2$3';
 
$subjects = array(
    'http://localhost',
    'https://example.com',
    ' ftp://example.com',
    'ftps://example.com ',
    'prefix http://example.com',
    'http://example.com suffix',
    'prefix http://example.com/path suffix',
    'prefix http://example.com/path&var=val suffix',
    'prefix http://example.com/path&var=val, suffix',
    'prefix http://example.com/path&var=val. suffix',
    'prefix "http://example.com/path&var=val" suffix',
    'prefix \'http://example.com/path&var=val\' suffix',
);
 
foreach ($subjects as $subject) {
    var_dump(preg_replace($pattern, $replacement, $subject));
}

Continuous Integration and development environment approach

Aleksandr Tsertkov — Mon, 25 Jan 2010 18:01:15 +0000

PHPDocTester – console script for evaluating your PHPDoc comments

Aleksandr Tsertkov — Tue, 19 Jan 2010 22:10:36 +0000

If you are fan of command line like me and do some PHP coding in console or simply keep console constantly opened than this script could be useful for you for quick evaluation of PHPDoc documentation generated for your PHP.

This script will generate PHPDoc documentation saving all files into temporary folder, display them in elinks console web browser and clear temporary folder after leaving browser. Script expects “elinks” and “phpdoc” to be installed on your system.

#!/bin/sh
PATH=/bin:/usr/bin:
 
# check input parameters
if [ "$#" -lt 1 ]; then
    echo "Usage:"
    echo "`basename $0` filename/dirname [options]"
    exit 1
fi
 
# create temporary directory
TARGET=`mktemp -dt phpdoctester.XXXXXX`
FILE=$1
 
# check if input is directory, otherwise assume it's file or filemask
if [ -d "$FILE" ]; then
    FCONFDIR="--directory"
else
    FCONFDIR="--filename"
fi
 
# create phpdoc documentation in temporary directory
phpdoc \
	$FCONFDIR "$FILE" \
	--target "$TARGET" \
	--parseprivate on \
	--undocumentedelements on \
	--output HTML:frames:default \
	|
	grep -P 'ERROR in |WARNING in ' \
	|
	sed -e 's/^\s*\(.*\)/\1/'
 
echo "\nPress any key to open phpdoc in console web browser..."
read
 
# show documentation in console browser
DOCFILE="${TARGET}/index.html"
elinks $DOCFILE 
 
# remove temporary directory
rm -r $TARGET

AJAX-based page update with graceful degradation

Aleksandr Tsertkov — Tue, 19 Jan 2010 22:00:46 +0000

This is a simplified POC showing how to use partial page update with AJAX when JavaScript is enabled but still have working website links in case of disabled JavaScript in client browser. It uses a bit of jQuery and PHP scripting.

Go directly to the demonstration. You can safely disable JavaScript in your browser (don’t forget to reload page though after that) and links still will work. You may also copy hash based links (http://www.devhands.com/wp-content/custom/smartlinks/#page3) and insert them into new browser tab, they also will work with enabled JavaScript.

Download full package or check the JavaScript logic right here:




    Smart links POCsmartlinks.tar
    
    
    


    Smart links Proof-Of-Concept
 
    
        This is a simplified example with combined direct (full page load) and ajax (partial content update) links with gracefull degradation. You can try disabling JavaScript in your browser at all.
        These links should be good to search engines as well. JavaScript history handling is not implemented here, though it's not hard to add it.
    
    
        page-1
        page-2 (+ css)
        page-3 (+ javascript)
    
 
    Loading data...
    <script type="text/javascript">
    /*
        $(document).ready(function(){
 
            var baseUri = function(location){
                return location.substr(0, location.lastIndexOf('/'));
            }(document.location.toString());
 
            //
            // if request was made to open concrete page or query string was not
            // empty reloadPageUrl will be populated with url which will be used
            // for all "smart" links (real page reload will happend)
            //
            // in our case this url will be site frontpage url
            //
 
            var reloadPageUrl = function(){
                if (document.location.search) {
                    return baseUri;
                } else {
                    return false;
                }
            }();
 
            //
            // intial page load (load partial content immediately after page has
            // been loaded)
            //
 
            if (!reloadPageUrl) {
                if (document.location.hash && '#' != document.location.hash) {
                    var page = encodeURIComponent(document.location.hash.substring(1));
                } else {
                    var page = 'page1';
                }
 
                $('#placeholder').load(baseUri + '?page=' + page + '&mode=partial');
            }
 
            //
            // click handler for "smart" links
            //
 
            $('a').click(function(event){
                var href = baseUri + this.getAttribute('devhands:href');
                var target = this.getAttribute('devhands:target');
                var hash = this.getAttribute('devhands:hash');
 
                if (href && target) {
                    if (hash && reloadPageUrl) {
                        document.location = reloadPageUrl + '#' + hash;
                        return false;
                    }
 
                    $(target).load(href);
 
                    if (hash) {
                        document.location = '#' + hash;
                    }
 
                    return false;
                }
            });
        });
    /*]]>*/
    script>

Scalable web architecture

Aleksandr Tsertkov — Tue, 19 Jan 2010 19:40:27 +0000

Domains whitelist for Exim smarthost

Aleksandr Tsertkov — Mon, 18 Jan 2010 22:40:05 +0000

Here is a quick hack for making a whitelist of destination domains for your exim smarthost configuration. It means that emails will be sent only to domains which you explicitly specify.

You may ask why “hack”? Because Exim will send bounce emails which most probably is not what you want, reject could be a better behavior.

Find your Exim configuration file for smarthost, /etc/exim4/exim4.conf.template under Ubuntu. And edit domains configuration parameter specifying colon separated list of allowed destination domains as a value.

domains = domain1.com:domain2.com

If your use Ubuntu update main configuration file by executing update-exim4.conf from command line as root user.

Subversion hook php framework

Aleksandr Tsertkov — Thu, 14 Jan 2010 20:49:41 +0000

Subversion provides very powerful hook system which allows extending it with custom logic. Hook is a command line script which is executed on selected repository event receiving metadata as command line arguments and providing results within output and exit code.

With a help of hook script you can validate commit log message or even submitted changes before saving them into repository and notify user if there are any errors.

If you have php on your server with a help of special PHP class your very powerful subversion hook might look like this:

#!/usr/bin/php

require '/var/svn/common-hooks/CommitTests.php';
putenv('PATH=/usr/bin');
 
new CommitTests($argv[1], $argv[2], array(
    'LogMessageLength' => array(3),
    'TabIndents' => array(array('php', 'phtml')),
    'TrailingSpaces' => array(array('php', 'phtml', 'ini')),
    'SvnProperties' => array(array(
        'php' => array('svn:keywords=Revision', 'svn:eol-style=LF'),
        'phtml' => array('svn:keywords=Revision', 'svn:eol-style=LF'),
        'html' => array('svn:eol-style=LF'),
    )),
));

This script have following pre-commit validation rules:

Minimum log message length is 3 characters
Tab indents are not allowed in *.php and *.phtml files
Trailing spaces are not allowed in *.php, *.phtml and *.ini files
*.php and *.phtml files should have following svn tags set: svn:keywords=Revision, svn:eol-style=LF
*.html files should have svn tag svn:eol-style=LF

Download CommitTests.php file.