PHP Cookbook, 2nd Edition

1.0. Strings in PHP are sequences of bytes, such as "We hold these truths to be self-evident" or "Once upon a time" or even "111211211." When you read data from a file or output it to a web browser, your data are represented as strings....

2.0. In everyday life, numbers are easy to identify. They're 3:00 P.M., as in the current time, or $1.29, as in the cost of a pint of milk. Maybe they're like #928;, the ratio of the circumference to the diameter of a circle. They can...

3.0. Displaying and manipulating dates and times seems simple at first but gets more difficult depending on how diverse and complicated your users are. Do your users span more than one time zone? Probably so, unless you are building a...

4.0. Arrays are lists: lists of people, lists of sizes, lists of books. To store a group of related items in a variable, use an array. Like a list on a piece of paper, the elements in array have an order. Usually, each new item comes af...

5.0. Along with conditional logic, variables are the core of what makes computer programs powerful and flexible. If you think of a variable as a bucket with a name that holds a value, PHP lets you have plain old buckets, buckets that co...

6.0. Functions help you create organized and reusable code. They allow you to abstract out details so your code becomes more flexible and more readable. Without functions, it is impossible to write easily maintainable programs because y...

7.0. PHP 5 has significantly improved support for object-oriented programming (OOP). This is a major change and a key reason to upgrade your code from PHP 4. If you're a fan of OOP, you will be very happy with the tools PHP 5 prov...

8.0. Web programming is probably why you're reading this book. It's why the first version of PHP was written and what continues to make it so popular today. With PHP, it's easy to write dynamic web programs that do almost anything. Othe...

9.0. The genius of PHP is its seamless integration of form variables into your programs. It makes web programming smooth and simple, speeding the cycle from web form to PHP code to HTML output. With that convenience, however, comes the...

10.0. Databases are central to many web applications. A database can hold almost any collection of information you may want to search and update, such as a user list, a product catalog, or recent headlines. One reason why PHP is such a...

11.0. As web applications have matured, the need for statefulness has become a common requirement. Stateful web applications, meaning applications that keep track of a particular visitor's information as he travels throughout a site...

12.0. XML has gained popularity as a data-exchange and message-passing format. As web services become more widespread, XML plays an even more important role in a developer's life. With the help of a few extensions, PHP lets you read a...

13.0. Most of the time, PHP is part of a web server, sending content to browsers. Even when you run it from the command line, it usually performs a task and then prints some output. PHP can also be useful, however, playing the role...

14.0. Web services allow you to exchange information over HTTP using XML. When you want to find out the weather forecast for New York City, the current stock price of IBM, or the cost of a flat screen TV on eBay, you can write a short s...

15.0. This chapter covers building web services. If you're unfamiliar with the fundamental concepts of web services, including REST, SOAP, and XML-RPC, jump back a chapter and read through Chapter 14. It provides the building blocks fo...

16.0. Before there was HTTP, there was FTP, NNTP, IMAP, POP3, and a whole alphabet soup of other protocols. Many people quickly embraced web browsers because the browser provided an integrated program that let them check their email, r...

17.0. With the assistance of the GD library, you can use PHP to create applications that use dynamic images to display stock quotes, reveal poll results, monitor system performance, and even create games. However, it's not like using...

18.0. Web application security is an important topic that's gaining more attention from both the developers who create web applications, and the attackers who try to exploit them. As a PHP developer, your applications are sure to be...

19.0. While everyone who programs in PHP has to learn some English eventually to get a handle on its function names and language constructs, PHP can create applications that speak just about any language. Some applications need to be...

20.0. The name programmer for those who spend their time developing web applications is misleading: the vast majority of time one spends "programming" is actually spent debugging. Whether you're fixing typos or refactoring chunks o...

21.0. PHP is pretty speedy. Usually, the slow parts of your PHP programs have to do with external resources'waiting for a database query to finish or for the contents of a remote URL to be retrieved. That said, your PHP code itself m...

Recipe 22.0. Regular expressions are an intricate and powerful tool for matching patterns and manipulating text. While not as fast as plain vanilla string matching, regular expressions are extremely flexible. They allow you to construct...

Recipe 23.0. The input and output in a web application usually flow between browser, server, and database, but there are many circumstances in which files are involved too. Files are useful for retrieving remote web pages for local pro...

Recipe 24.0. A filesystem stores a lot of additional information about files aside from their actual contents. This information includes such particulars as the file size, directory, and access permissions. If you're working with files...

25.0. PHP was created for web programming and is still used mostly for that purpose. However, PHP is also capable as a general-purpose scripting language. Using PHP for scripts you run from the command line is especially helpful when t...

26.0. PEAR is the PHP Extension and Application Repository, a collection of open source classes that work together. Developers can use PEAR classes to parse XML, implement authentication systems, make SOAP requests, send MIME mail wi...