MediaWiki Implementation

Note: Not yet installed on this wiki.

A MediaWiki extension to allow us to handle Geohashes a little nicer and more automatically. Any questions to the talk page here, although I would appreciate a poke on my talk page also.

Note that the whole algorithm is not fully implemented, because those on IRC said that templates could do the rest.

--Edgemaster 21:39, 23 May 2008 (UTC)

Installation

• Drop the code below into mediawiki/extensions/geohashes.php
• Add the following to mediawiki/LocalSettings.php:

require_once "$IP/extensions/geohashes.php";

• Check Special:Version to confirm installation

The Code

Feel free to tidy it up, poke an admin if you feel your changes are worthy to be deployed on this wiki.

<?php
$wgExtensionCredits[$type][] = array(
    'name' => "Geohashing MediaWiki Parser Functions",
    'description' => "Adds {{#md5}} and {{#dow}} handlers",
    'descriptionmsg' => "",
    'version' => "1.01",
    'author' => "Edgemaster (grand.edgemaster@gmail.com)",
    'url' => "http://wiki.xkcd.com/geohashing/MediaWiki_Implementation"
);

$wgExtensionFunctions[] = 'geohashingFunction_Setup';
$wgHooks['LanguageGetMagic'][]       = 'geohashingFunction_Magic';
 
function geohashingFunction_Setup() {
    global $wgParser;
    $wgParser->setFunctionHook( 'md5', 'geohashingMd5Function_Render' );
    $wgParser->setFunctionHook( 'dow', 'geohashingDowFunction_Render' );
}
 
function geohashingFunction_Magic( &$magicWords, $langCode ) {
    $magicWords['md5'] = array( 0, 'md5' );
    $magicWords['dow'] = array( 0, 'dow' );
    return true;
}
 
function geohashingMd5Function_Render( &$parser, $src = '', $half = 0, $decimal = 0) {
    $md5 = md5(trim($src));
    if(!$half) return $md5;
    
    $md5 = substr($md5, ($half-1)*16, 15);
    if(!$decimal) return $md5;
    
    $dec = ('0x'.$md5) / pow(16,15);
    return $dec;
}

function geohashingDowFunction_Render( &$parser, $Y = 0, $m = 0, $d = 0) {
    foreach(array('Y', 'm', 'd') as $var) {
        $$var = intval($$var);
        if($$var < 10) $$var = '0' . $$var;
        if(!intval($$var)) $$var = date($var);
    }
    return trim(@file_get_contents("http://irc.peeron.com/xkcd/map/data/$Y/$m/$d"));
    // file_get_contents returns nothing on http error, we hide the warning from php
}
?>

Note: Passing all 16 hex-characters causes PHP to misinterpret sign when decimalising, so we only pass the first 15... besides, that still gives microscopic accuracy. Hence the 15s in lines 30 and 33 above.

In-wiki Usage

This extension adds two new parser functions: {{#md5}} and {{#dow}}.

#md5

md5s a string, optionally splitting into halves and decimalising.

{{#md5:string|halve|decimal}}

Parameters:

• string: the string to md5
• halve: (optional) splits the hash into two, as required by The Algorithm. 0 = do not half, 1 = first half, 2 = 2nd half. Defaults to 0.
• decimal: (optional) converts the half to decimal if set. Defaults to 0, requires halve to be set to 1 or 2!

Examples:

• {{#md5:testing testing!}}: f9da4c546dff04d46e1fab3ca0456b42
• {{#md5:2005-05-26-10458.68}}: db9318c2259923d08b672cb305440f97
• {{#md5:2005-05-26-10458.68|0}}: db9318c2259923d08b672cb305440f97
• {{#md5:2005-05-26-10458.68|1}}: db9318c2259923d
• {{#md5:2005-05-26-10458.68|2}}: 8b672cb305440f9
• {{#md5:2005-05-26-10458.68|1|1}}: 0.857713267707
• {{#md5:2005-05-26-10458.68|2|1}}: 0.54454306955928

#dow

Fetches the opening Dow Index for a date from the irc.peeron.com service.

{{#dow:year|month|day}}

Parameters:

• year: 4 digit year
• month: month (1 or 2 digits are acceptable)
• day: day (1 or 2 digits are acceptable)

The only validation done is to check the values are non-null. If any of the 3 are null (or all of the 3), then today's date will be used instead. (Always requires the colon to produce a result)

Examples:

• {{#dow:}}: 41956.34
• {{#dow:2005|05|26}}: 10458.68
• These will fail:
  • (lack of data) {{#dow:1854|05|26}}:
  • (bad syntax) {{#dow}}: {{#dow}}

Variables Extension too plz

Installing

Copy this into a file called $mediwikipath/extensions/Variables/Variables.php:

<?php

if ( !defined( 'MEDIAWIKI' ) ) {
    die( 'This file is a MediaWiki extension, it is not a valid entry point' );
}

$wgExtensionFunctions[] = 'wfSetupVariables';

$wgExtensionCredits['parserhook'][] = array(
	'name' => 'Variables',
	'url' => 'http://www.mediawiki.org/wiki/Extension:VariablesExtension',
	'author' => 'Rob Adams',
	'description' => 'Define page-scoped variables'
);

$wgHooks['LanguageGetMagic'][]       = 'wfVariablesLanguageGetMagic';

class ExtVariables {
    var $mVariables;

    function vardefine( &$parser, $expr = '', $value = '' ) {
	$this->mVariables[$expr] = $value;
	return '';
    }

    function varf( &$parser, $expr = '' ) {
	return $this->mVariables[$expr];
    }
}

function wfSetupVariables() {
    global $wgParser, $wgMessageCache, $wgExtVariables, $wgMessageCache, $wgHooks;

    $wgExtVariables = new ExtVariables;

    $wgParser->setFunctionHook( 'vardefine', array( &$wgExtVariables, 'vardefine' ) );
    $wgParser->setFunctionHook( 'var', array( &$wgExtVariables, 'varf' ) );
}

function wfVariablesLanguageGetMagic( &$magicWords, $langCode = 0 ) {
	require_once( dirname( __FILE__ ) . '/Variables.i18n.php' );
	foreach( efVariablesWords( $langCode ) as $word => $trans )
		$magicWords[$word] = $trans;
	return true;
}

Copy this into a file called $mediwikipath/extensions/Variables/Variables.i18n.php:

<?php

/**
 * Get translated magic words, if available
 *
 * @param string $lang Language code
 * @return array
 */
function efVariablesWords( $lang ) {
	$words = array();

	/**
	 * English
	 */
	$words['en'] = array(
		'var' 		=> array( 0, 'var' ),
		'vardefine' 	=> array( 0, 'vardefine' ),
	);

	# English is used as a fallback, and the English synonyms are
	# used if a translation has not been provided for a given word
	return ( $lang == 'en' || !isset( $words[$lang] ) )
		? $words['en']
		: array_merge( $words['en'], $words[$lang] );
}

Then add

require_once( "$IP/extensions/Variables/Variables.php" );

to the end of LocalSettings.php.