On the NetTuts.com site there's a new tutorial showing you how to introduce the Memcached tool to your application - a quick and easy way to cache data and optimize performance.

Your latest PHP/MySQL website is finally online. And it's awesome. But it's not as fast as you want it to be, because of the many SQL queries running every time a page is generated. And above that, you have the feeling it will not scale well under heavy loads. And you are most likely right. In this tutorial, we will see how you can greatly improve your website's responsiveness [...] by implementing a cache layer between your code and your database. The good news is it is fairly easy, and can be done in a few minutes!

They help you get the memcached server installed (a one-liner in most linux distributions) and how to install the memcached extension using PECL. Code is included showing you how to connect to the server, store data into the cache based on a generated key and how to pull the same data back out.

In this recent post to his blog Stuart Herbert introduces a system he's created to handle "contracts" in PHP development - ContractLib.

Programming contracts are tests around functions and methods, and they are normally used: to catch any 'bad' data that has been passed into the function or method from the caller, and to catch any 'bad' data generated by the function or method before it can be returned to the caller. These are pre-condition and post-condition tests, and they are tests that either pass or fail.

He points out that by having contracts you not only increase the robustness of your code but you also save time not trying to hunt down data-related issues. Using pre-conditions, you can can check data to ensure things like correct formatting, data that's out of range and data that might be missing. His ContractLib comes with a set of tests that provide good examples of how to use the functionality. Installation instructions are included.

On DevShed.com today there's the first part of a two-part series showing how to build self-contained validator objects that can be used to test the format of user input for validity.

In this two-part tutorial, I show why the use of static helper classes can be detrimental to building robust and scalable object-oriented applications in PHP (though you should take into account that the concept is language agnostic). I also implement a set of instantiable, fine-grained validators, which can be easily tested in isolation, injected into the internals of other objects, and so forth.

Their set of "concrete validators" are all based off of a validator interface/abstract class and check things like email formatting, floats, integers and URLs. Also included are a few examples of using the validators in a sample script.

On her blog today Lorna Mitchell has a quick tip for anyone having an issue sending POSTed JSON data with the curl functionality that can be built into PHP. The trick to her method is sending things with the right header.

We can't send post fields, because we want to send JSON, not pretend to be a form (the merits of an API which accepts POST requests with data in form-format is an interesting debate). Instead, we create the correct JSON data, set that as the body of the POST request, and also set the headers correctly so that the server that receives this request will understand what we sent.

She includes a code example (about ten lines) showing the POSTing process that sets up options using curl's curl_setopt. Be sure to set up the headers to send as "application/json" - that's the trick to letting the remote end know the format.

In a recent post to his blog Brian Swan takes a look at working with sessions in PHP and, specifically, how to save them to Azure along with all of their data.

In my last post, I looked at the session handling functionality that is built into the Windows Azure SDK for PHP, which uses Azure Tables or Azure Blobs for storing session data. As I wrote that post, I wondered how easy it would be to use SQL Azure to store session data, especially since using a database to store session data is a common and familiar practice when building distributed PHP applications. As I found out, using SQL Azure to store session data was relatively easy (as I'll show in this post), but I did run into a couple of small hurdles that might be worth taking note of.

He uses PHP's own session_set_save_handler to point to his custom Azure handling class with the needed methods (like write, close and destroy). He breaks it out into three simple steps, some with a bit of code attached:

• Create the database, table, and stored procedure
• Add the SqlAzureSessionHandler class to your project
• Instantiate SqlAzureSessionHandler before calling session functions as you normally would

The code for the Azure handling class can be downloaded here.

On PHPBuilder.com today there's a new tutorial helping you integrate weather data into your site with the help of the Services_Weather PEAR package.

Regardless of whether you consider the weather to be an obsession or nuisance, there are plenty of opportunities to incorporate weather-related data into your Web application. The Services_Weather PEAR Package offers what is perhaps the easiest way to begin retrieving weather-related data.

Included in the post are the commands you'll need to get the package installed (via the PEAR installer) and sample code to set up the connection - in this case to Weather.com - to fetch the results for a search location. The "search" method will return the best guesses for your input and give you the unique code to use for fetching other values, like the current forecast.

In a new tutorial from NetTuts.com today they show you how to combine a CodeIgniter-based backend and a jQuery frontend to make a simple Ajax data grid of data pulled from a database.

In this lesson, we will create a CodeIgniter library that allows us to generate data grids automatically for managing any database table. I'll explain each step required to create this class; so you'll likely learn some new OOP techniques/concepts in the process! As a bonus, we'll proceed to write some jQuery code that will enable a user to update the data grid's content without having to wait for a page refresh.

The tutorial's broken up into a few different steps, each complete with descriptions and plenty of code ready for cut-and-paste:

• Build a Data Grid Generator Class (a helper in PHP)
• Testing the Datagrid Helper Class with a CodeIgniter Controller
• Implementing Ajax (jQuery to the Rescue!)
• Check All or Nothing!

You can also download the source for all of the scripts if you'd like to dive right into the code.

James Morris has a quick tutorial today showing how to pull the exif data from a photo and make it into something useful you can either display on on the site or store for categorization.

Today I spent a good amount of time trying to figure out how to strip exif data from an image using Imagick. The first port of call was the (pathetic) documentation at php.net. I searched for 'exif' but found nothing. [...] I was tipped off by a colleague to the method Imagick::stripImage() which apparently did what I wanted. The only mention of exif is in a rather helpful comment at the bottom of the page.

This comment pointed him to the Imagick::stripImage() function that pulls off the data and returns exif information (or, as the documentation calls it, "profiles and comments"). His seven line script is included in the post that initializes the Imagick object, pulls in the file and runs the stripImage() method with the option for "exif:*". The resulting properties are then displayed including aperature value, date taken, exposure time, make and model of the camera, shutter speed, resolution and much more.

DevShed has posted a new article in their series looking at storage interfaces and how to use them. In this latest article they show how to create a caching layer that will allow you to work with any sort of caching backend you'd like.

As with other elements of object-oriented programming, it's possible to use segregated interfaces in a great variety of scenarios and conditions and, therefore, enjoy the benefits that they provide right out of the box. [...] My goal in this article is to create an extendable caching system based on the contract defined by a segregated interface. To achieve this, the first step we need to take is to create the interface in question.

He shows how to create the "CacheableInterface" that provides the structure for the child interfaces to follow. It provides methods for setting, getting, deleting and checking to see if a key exists. They illustrate its use with an interface to an APC cache, a file caching and a class that uses dependency injection to define the interface to use.

On PHPBuilder.com today Jason Gilmore has posted a tutorial showing you how to use the PEAR HTML_Table component to quickly and easily display tabular information on your site.

Because the task [of building tables] is so commonplace, personally I prefer to treat it like stamping out a widget, and rely on a drop in solution. While several such standardized solutions are available, I generally prefer to use HTML_Table, a great PEAR package which makes tabular data presentation a breeze. In this tutorial I'll walk you through several of HTML_Table's key features, additionally showing you how to integrate CSS and jQuery to create an eye-appealing and interactive tabular layout in no-time flat.

He helps you through the install (using the PEAR installer) and starts you down the right path with some sample code creating a table based off some example data from an array. He shows how to add headers, put in some CSS for styling them and for making the rows highlight on mouseover. He finishes it with the jQuery bit that uses the tablesorter feature to dynamically allow sorting of the table based on the values in each column.