MediaWiki ResourceLoader startup diff

rl-startup-diff.php

<?php

$startupUrls = [
	'enwiki-canonical' => 'https://en.wikipedia.org/w/load.php?lang=en&modules=startup&only=scripts&raw=1&skin=vector',
	'enwiki-mobile' => 'https://en.m.wikipedia.org/w/load.php?lang=en&modules=startup&only=scripts&raw=1&skin=minerva&target=mobile',
];

define( 'STARTUPREG_JSON_START', 'mw.loader.register([' );
define( 'STARTUPREG_JSON_START_OFFSET', 'mw.loader.register(' );
define( 'STARTUPREG_JSON_END', ']);' );
define( 'STARTUPREG_JSON_END_OFFSET', ']' );
define( 'STARTUPREG_CACHE_PREFIX', __DIR__ . '/startup-reg-cache-' );

function httpGet( string $url ): string {
	ini_set(
		'user_agent',
		'rl-startup-reg-diff.php (Author: <https://meta.wikimedia.org/wiki/User:Krinkle>)'
	);
	$result = file_get_contents( $url );
	if ( !$result ) {
		throw new Exception( 'HTTP request failed' );
	}
	return $result;
}

function getModuleVersions( string $label, string $url ): array {
	$js = httpGet( $url );

	$pos = strpos( $js, STARTUPREG_JSON_START );
	if ( $pos === false ) {
		throw new Exception( 'Startup response did not contain STARTUPREG_JSON_START' );
	}
	$js = substr( $js, $pos + strlen( STARTUPREG_JSON_START_OFFSET ) );

	$pos = strpos( $js, STARTUPREG_JSON_END );
	if ( $pos === false ) {
		throw new Exception( 'Startup response did not contain STARTUPREG_JSON_END' );
	}
	$js = substr( $js, 0, $pos + strlen( STARTUPREG_JSON_END_OFFSET ) );

	// echo $js;
	$data = json_decode( $js, true, 512, JSON_THROW_ON_ERROR );
	// var_dump( $data );

	$versions = [];
	foreach ( $data as $module ) {
		list( $name, $version ) = $module;
		$versions[$name] = $version;
	}
	return $versions;
}

foreach ( $startupUrls as $label => $url ) {
	$cacheFile = STARTUPREG_CACHE_PREFIX . $label . '.json';
	$oldVersions = @file_get_contents( $cacheFile );
	$oldVersions = $oldVersions ? json_decode( $oldVersions, true ) : false;

	$versions = getModuleVersions( $label, $url );

	if ( $oldVersions ) {
		foreach ( $versions as $module => $newVersion ) {
			$oldVersion = $oldVersions[$module] ?? null;
			if ( !$oldVersion ) {
				echo "[$label] New module: $module\n";
				continue;
			}
			if ( !$newVersion ) {
				echo "[$label] Removed module: $module\n";
				continue;
			}
			if ( $oldVersion !== $newVersion ) {
				echo "[$label] Changed module: $module `$oldVersion` => `$newVersion`\n";
				continue;
			}
		}
	}

	file_put_contents( $cacheFile, json_encode( $versions, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES) . "\n" );
}