public static function getContentHash($composerFileContents)
    {
        $content = json_decode($composerFileContents, true);

        $relevantKeys = array(
            'name',
            'version',
            'require',
            'require-dev',
            'conflict',
            'replace',
            'provide',
            'minimum-stability',
            'prefer-stable',
            'repositories',
            'extra',
        );

        $relevantContent = array();

        foreach (array_intersect($relevantKeys, array_keys($content)) as $key) {
            $relevantContent[$key] = $content[$key];
        }
        if (isset($content['config']['platform'])) {
            $relevantContent['config']['platform'] = $content['config']['platform'];
        }

        ksort($relevantContent);

        return md5(json_encode($relevantContent));
    }