Fix W3 Total Cache W3_Plugin_TotalCache::ob_callback() expected to be a reference

Around a year ago I was playing with W3 Total Cache plugin on HHVM while I got an annoying warning

Warning: Parameter 1 to W3_Plugin_TotalCache::ob_callback() expected to be a reference, value given in /wp-includes/functions.php on line 3269

The funny part is that one of the functions was passing by reference which I still could not find the reason for it, maybe it was a limitation in PHP 4.3. Removing one character “&” fixed the issue so I submitted a pull request to the author although the repository currently does not accept pull request. Later on as PHP 7.0 was released, the issue started to show on PHP as well which brought more attention to this small fix. The users comments included anger such as user @kmob2 who said

this is becoming a running gag

Even more user @pratham2003 proposed a one line bash command to solve the problem

sed -i.bak 's/function ob_callback(&/function ob_callback(/g' /path/to/public_html/wp-content/plugins/w3-total-cache/lib/W3/Plugin/TotalCache.php

I hope that the developers will finally listen to the users and fix it soon!

Custom validation messages for sails js

//in api/models/User.js
function validationError(invalidAttributes, status, message) {
  var WLValidationError = require('../../node_modules/sails/node_modules/waterline/lib/waterline/error/WLValidationError.js');
  return new WLValidationError({
      invalidAttributes: invalidAttributes,
      status: status,
      message: message
var User = {
  attributes: {
  ownValidate:: function (values, update, cb) {
    //example of not allowed param on update
    //if it is an update then do not allow email param
    if (update && {
      return cb(validationError({
        email: [
            message: 'Email is not allowed for updates.'
      }, 400 /*status*/));
    sails.models['user'].findOne( (err, user) {
      if (err) return cb(err);
      if (user) {
        return cb(validationError({
          email: [
              rule: 'E_UNIQUE'
              /* unique validation message is left for the default one here */
        }, 409));
  beforeCreate: function (values, cb) {
    return sails.models['user'].ownValidate(values, false, cb);
  beforeUpdate: function (values, cb) {
    return sails.models['user'].ownValidate(values, true, cb);

For blueprint custom messages validation

Disqus problem with wordpress “unable to connect to the disqus api servers”

I recently installed Disqus plugin for WordPress; however, I have been receiving this message “unable to connect to the disqus api servers.” By looking into the source code, it looks like curl is the problem! more specifically the _dsq_curl_urlopen() function, but I did not investigate this error further. As fortunately, we can easily switch to the alternative function _dsq_fsockopen_urlopen().

install memcached 1.4.13 on CentOS 6.2

– Make sure to check PHP-FPM and MYSQL posts.

– One of the dependencies of memcache is libevent, get latest version from

mkdir libevent
cd libevent
tar xfz libevent-2.0.17-stable.tar.gz
cd libevent-2.0.17-stable

– get latest version from

Ban IP from logging in for 5 minutes after 10 failed logins

if( login_limit() )
   die( 'Your IP has been banned from logging in for the next 5 minutes' );

 * Counts login times by same IP 
 * returns true if limit reached or false if not 
function login_limit(){
    //get real IP if user behind proxy noted by Sebastian Enger
    //user still banned from login
    if( _cache( $ip . 'banned' ) )
        return true;

    //number of seconds 
    $sec = 30;
    //find ip info array in cache saved less than $sec ago
    if( ($ip_info=_cache( $ip ))  && $ip_info[0] > time()-$sec ){
        //user login 10 times during last $sec 
        if(  $ip_info[1] > 10 ){
            //ban user ip for the next 5 minutes
            _cache( $ip . 'banned', 1, 0, 60*5 );
            _cache( $ip, -1 );
            return true;
        //increase login retries +1 
        _cache( $ip, array(  $ip_info[0],   ++$ip_info[1] ), 0, $sec );
        return false;
    //add ip info to cache
    _cache( $ip, array( time(), 1 ), 0, $sec );
    return false;

function _cache( $name, $val=NULL, $ttl=false ){
	global $mcdb;
	if(empty($mcdb) ) 
		$mcdb = memcache_connect('unix:///etc/sockets/memcached.sock', 0);
	if($val === -1){
		return memcache_delete($mcdb,$name);
	}elseif( $val !== NULL ){
		return memcache_set($mcdb,$name,$val, false, $ttl);
		$retval = memcache_get($mcdb,$name);
		return  $retval ? $retval : NULL;