htaccess rewrite Master Class! If you understand the basics of mod_rewrite, or if you literally write the mod_rewite.c code, this article will transform your thinking. The transformation is profound. Deeply effective. Culmination of the best of the best mod_rewrite tricks for understanding and learning exactly what rewrite is doing.

We've figured out what mod_rewrite variables look like, a cheatsheet of the actual value.

Here's a nifty little idea I had that has some merit and is super easy. Separate favicons for separate areas of a site. Basically, I can't live without Firefox or Chrome and the way they use multiple tabs, having about 20-50 open at any one time.. But that makes it more difficult to find the right tab!

While reading up on gethostbyaddr on PHP.net, I saw a nice idea for using fsockopen to connect over UDP port 53 to any Public DNS server, like Google DNS 8.8.8.8, and sending the reverse addr lookup in oh about 100 bytes, then getting the response in oh about 150 bytes! All in less than a second. This is how/why to read/write data directly to the wire! This would be extremely valuable for use in things like my online header tool because it's faster than any other method. As usual, I went a bit overboard optimizing it to be lean and fast.

PHP's fsockopen function lets you open an Internet or Unix domain socket connection for connecting to a resource, and is one of the most powerful functions available in the php language.

Recently I had to setup a script to curl 10k urls, but it could only do 500 requests at any one time. In order to work under that limit, I created a function that returns the number of currently running processes on the machine in an extremely fast and efficient way, thus allowing the curl_multi requests to queu themselves such as GNU xargs.

Problem: WordPress shows pages, categories, author pages, etc. without an ending '/'.
/about instead of /about/.
/category/htaccess instead of /category/htaccess/.

Solution: Either hook into the user_trailingslashit filter, or use some htaccess RedirectMatch

The Admin Bar in WordPress is always shown when in the backend administration area no matter what.

You are given the option to show/hide the admin bar when viewing the site, but there is no option to show/hide the admin bar when using the backend... So I created a plugin to provide that option on profile pages.

Why hide the admin bar in backend?
Normally I like the admin-bar and usually have it enabled, but it's nice to be able to switch it on/off from the "Edit Profile" page. The biggest reason for not loading/showing the admin_bar in the backend is SPEED. Here are 2 instances where I hide it-

    · Sites with many authors/admins
    · Moderating Comments on a Mobile Phone

There are a total of 57 HTTP Status Codes recognized by the Apache Web Server. Wouldn't you like to see what all those headers and their output, ErrorDocuments look like?

Fast, HTTP Protocol, protection. If you are reading this article, you already know enough about the benefits of making sure your site can handle HTTP Protocol Errors. This is a nice single php file with no dependencies or requirements, will work on anything. Optimized for minimizing bandwidth and resource-hogging connections from bots and spambots.

<?php
ob_start();
@set_time_limit(5);
@ini_set('memory_limit', '64M');
@ini_set('display_errors', 'Off');
error_reporting(0);

So, here's what I hacked together last night, that is being used today. It's essentially 2 files.

1. A php file that scrapes uses curl to scrape all the urls for the page (favicon, css, images, pdfs, etc..)
2. A simple bash shell script acting as a cgi that creates a zip file of all the urls, and a self-extracting exe file for those without a winzip tool

If you have a php.cgi or php.ini file in your /cgi-bin/ directory or other pub directory, try requesting them from your web browser. If your php.ini shows up or worse you are able to execute your php cgi, you'll need to secure it ASAP. This shows several ways to secure these files, and other interpreters like perl, fastCGI, bash, csh, etc.

What they say about kung-fu is true..

It can be attained by anyone through hard work over time. You can become as good as the amount of work you put in. Here's a short look at a basic technique that I use. Simply reverse engineering the source code and taking notes along the way...

static void php_session_send_cookie(TSRMLS_D)
  if (SG(headers_sent)) {
          if (output_start_filename) {
                  php_error_docref(NULL TSRMLS_CC, E_WARNING, "Cannot send session cookie - headers already sent by (output started at %s:%d)",
                          output_start_filename, output_start_lineno);
          } else {
                  php_error_docref(NULL TSRMLS_CC, E_WARNING, "Cannot send session cookie - headers already sent");
          }
          return;
  }

  /* URL encode session_name and id because they might be user supplied */
  e_session_name = php_url_encode(PS(session_name), strlen(PS(session_name)), NULL);

For the AskApache Google 404 WordPress Plugin update I added a new 404.php that is more advanced than anything previously seen for a 404.php

Ever wanted to execute commands on your server through php? Now you can. I'm calling this file (see below) shell.php and it allows you to run commands on your web server with the same permissions that your php executable has.

Just a very brief look at speeding up form submission by delegating the processing and bandwidth to your server, not your client.

• When php run as Apache Module (mod_php)
• When php run as CGI
• When cgi?d php is run with wrapper (for FastCGI)