Encoding & Decoding PHP Code

There are many ways to encode and decode PHP code. From the perspective of site security, there are three PHP functions — str_rot13(), base64_encode(), and gzinflate — that are frequently used to obfuscate malicious strings of PHP code. For those involved in the securing of websites, understanding how these functions are used to encode and decode encrypted chunks of PHP data is critical to accurate monitoring and expedient attack recovery. Read more »

Roll Your Own “What’s My IP Address?” Page

My current ISP likes to keeps things spicy by changing my IP address every few months or so. There are a million ways to get this changing IP information, but as an obsessive web developer, I like to roll my own whenever possible. That means using my own resources instead of spending time and energy elsewhere. So the goal for this project is to create a web page that does one thing very well: display the visitor’s current IP information. In this tutorial, we use PHP, HTML, CSS, and JavaScript to roll our own sleek & stylish “What’s my IP” […] Read more »

Huge Collection of Code Snippets: HTAccess, PHP, WordPress, jQuery, HTML, CSS

Please excuse this self-serving, miscellaneous post, but I’ve just got to purge all of these code snippets and scraps collected over the years. Whenever I update this site, I place any removed/unused code snippets into a giant note file for future reference, just in case. There’s all sorts of different types of code and snippets that just keep growing and growing and.. and finally it gets to a point where I just need to dump everything and start fresh. That is the purpose of this post. Read more »

Block Tough Proxies

If you want to block tough proxies like hidemyass.com, my previously posted .htaccess methods won’t work. Those methods will block quite a bit of proxy visits to your site, but won’t work on the stealthier proxies. Fortunately, we can use a bit of PHP to keep them out. Read more »

Ajax-Powered Error Logs

Update: Check out the new and improved Ajax Error Log Version 2.0! As an obsessive website administrator, I like to keep a keen eye on my error logs. Once a week, I download my PHP, 404, and other error logs, and analyze them as closely as time allows. Monitoring site errors and other traffic patterns leads to many of the security-related articles I post here at Perishable Press, including resources such as the 5G Blacklist, Ultimate HTAccess Blacklist, and the Blacklist Candidate Series. Easily, one of the best ways to protect your site is to understand the different types of […] Read more »

Upload Large Files or Die Trying

I recently spent some time wrestling with various e-commerce/shopping-cart/membership plugins. One of them was of course the popular WP e-Commerce plugin, which uses a directory named “downloadables” to store your precious goods. I had some large files that needed to go into this folder, but the server’s upload limit stopped me from using the plugin’s built-in file uploader to do so. Read more »

Ajax RSS Feeds with More Sidebar

After implementing Chris Coyier’s More Sidebar technique here at Perishable Press, I needed a good source of “filler” content for the “more” blocks. After experimenting with multiple loops and template tags, the idea of sliding in RSS feeds seemed like a better solution. Replacing some empty space with great content is a win-win for everyone. For example, I display a few of my recent tweets in the sidebar to help fill a lil’ space. It’s a great way to share stuff, and it’s pretty easy to do. Read more »

PHP Tip: Encode & Decode Data URLs

Converting small images to data-URLs is a great way to eliminate HTTP requests and decrease loading time for your pages. Using PHP‘s base64_encode() and base64_decode() functions, we have the power to convert images to data-URLs and vice-versa. Read more »

Display Latest Tweet with Show/Hide Cookies

Update (2013/08/03): This simple technique no longer works thanks to the 2013 Twitter API, which makes it much more complicated to grab your latest tweet. For WordPress, check out the Latest Tweets Widget. My previous theme displays my latest tweet at the top of every page. It turned out to be an excellent technique for getting more followers – visitors see the tweet, click the link, and possibly follow me on Twitter. There is even a cookie-powered “Hide” link for uninterested visitors to hide the tweet for awhile. I received quite a few requests for a tutorial on the technique, […] Read more »

HTTP Headers for ZIP File Downloads

You know when you you’re working on a project and get stuck on something, so you scour the Web for solutions only to find that everyone else seems to be experiencing the exact same thing. Then, after many hours trying everything possible, you finally stumble onto something that seems to work. This time, the project was setting up a secure downloads area for Digging into WordPress. And when I finally discovered a solution, I told myself that it was definitely something I had to share here at Perishable Press. Apparently, there is much to be desired when it comes to […] Read more »

Protect Your Site with a Blackhole for Bad Bots

One of my favorite security measures here at Perishable Press is the site’s virtual Blackhole trap for bad bots. The concept is simple: include a hidden link to a robots.txt-forbidden directory somewhere on your pages. Bots that ignore or disobey your robots rules will crawl the link and fall into the trap, which then performs a WHOIS Lookup and records the event in the blackhole data file. Once added to the blacklist data file, bad bots immediately are denied access to your site. I call it the “one-strike” rule: bots have one chance to follow the robots.txt protocol, check the […] Read more »

Fixing WordPress Infinite Duplicate Content Issue

Jeff Morris recently demonstrated a potential issue with the way WordPress handles multipaged posts and comments. The issue involves WordPress’ inability to discern between multipaged posts and comments that actually exist and those that do not. By redirecting requests for nonexistent numbered pages to the original post, WordPress creates an infinite amount of duplicate content for your site. In this article, we explain the issue, discuss the implications, and provide an easy, working solution. Understanding the “infinite duplicate content” issue Using the <!–nextpage–> tag, WordPress makes it easy to split your post content into multiple pages, and also makes it […] Read more »

Is it Secret? Is it Safe?

Whenever I find myself working with PHP or messing around with server settings, I nearly always create a phpinfo.php file and place it in the root directory of whatever domain I happen to be working on. These types of informational files employ PHP’s handy phpinfo() function to display a concise summary of all of your server’s variables, which may then be referenced for debugging purposes, bragging rights, and so on. While this sort of thing is normally okay, I frequently forget to remove the file and just leave it sitting there for the entire world to look at. This of […] Read more »

Stupid WordPress Tricks

One of the most popular articles here at Perishable Press is my January 2005 post, Stupid htaccess Tricks. In that article, I bring together an extensive collection of awesome copy-&-paste HTAccess code snippets. Four years later, people continue to tell me how much they enjoy and use the content as a bookmarked reference for many of their HTAccess needs. The article was even published in a book on Joomla! Security. This is very inspiring to me, so I have decided to create a similar post for all of the useful WordPress code snippets, tips and tricks that I have collected […] Read more »

Pimp Your 404: Presentation and Functionality

I have been wanting to write about 404 error pages for quite awhile now. They have always been very important to me, with customized error pages playing a integral part of every well-rounded web-design strategy. Rather than try to re-invent the wheel with this, I think I will just go through and discuss some thoughts about 404 error pages, share some useful code snippets, and highlight some suggested resources along the way. In a sense, this post is nothing more than a giant “brain-dump” of all things 404 for future reference. Hopefully you will find it useful in pimping your […] Read more »

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