Libraries : PHP

The following is an alphabetically sorted list of the libraries:

Apache HTTP server functions: Includes a function to retrieve all HTTP headers, getallheaders( ).
Array functions: There are almost 50 functions to sort, merge, split, iteratively process, and return information about arrays. We discuss many of these functions in detail in Chapter 2.
BCMath arbitrary precision mathematics functions: A library of functions to perform high-precision calculations with large numbers.
Bzip compression functions: Tools to read and write files compressed with Julian Seward's highly effective compression algorithm; however, it's a bit slow compared to gzip.
Calendar functions: For conversion between various calendars, including the Jewish and Gregorian calendars, and for finding the date of Easter.
CCVS API functions: RedHat's solution for credit card transaction processing.
Character type functions: Additional string functions to check what characters are contained within a string. These can be used as a replacement for or in addition to the validation methods described in Chapter 7.
ClibPDF function library: Requires purchase of a license if used for commercial applications: The ClibPDF library accesses a set of C functions for creating Adobe PDF documents. The C library ClibPDF is available from http://www.fastio.com along with a licensing agreement.
CURL (client URL library) functions: Functions that communicate with resources using the FTP, gopher, HTTP, LDAP, Telnet, and other protocols.
Database functions: The MySQL library functions are discussed in detail in Chapter 4, with additional information on some functions in Chapter 5 and Chapter 6. Techniques for using the other DBMS libraries to connect to selected DBMSs are discussed briefly at the end of Chapter 4. Many other DBMS libraries are also available and detailed in the PHP manual; we don't discuss them here.
Date and time functions: The basics of date and time functions are described in Chapter 2. Examples are also discussed in Chapter 7.
Direct IO functions: A function library that accesses a file descriptor. The library is C-like in functionality, and C programmers will feel at home with the functions.
Directory functions: Changes directories in the filesystem, list files in a directory, etc.
Error handling and logging functions: Functions to change error reporting. Controlling the severity of PHP errors that are detected for debugging purposes is discussed in Chapter 2, and custom error handlers are discussed in Chapter 10.
Encryption functions: Selected encryption functions for producing cipher-text from plain text-and reversing the process-are discussed in Chapter 9.
eXtensible Markup Language (XML) functions: XML is a data format for structured document interchange, and this library provides tools to parse and retrieve components of XML documents.
Filesystem functions: Retrieves information about files, creates and modifies attributes of files, reads and writes files, and performs many other low-level file operations.
Forms Data Format functions: Tools to handle form data sent using the Forms Data Format (FDF) that's part of Adobe's PDF standard.
FTP: Functions that implement the File Transfer Protocol.
Functions functions: Seriously! A set of functions that inspects whether a function exists and returns details, such as the number of parameters to a function.
GNU teletext: A GNU project to internationalize programs by making substitution of program output messages in different languages easier.
GMP functions: More math functions for arbitrary-length integers using the GNU MP library; an alternative to the BCMath library described earlier in this section.
HTTP functions: The header( ) function creates HTTP headers in a response to a web browser. It is discussed and used in examples in Chapter 5 to Chapter 13. The function setcookie( ) sets a cookie in a web browser and is discussed in Chapter 8.
Hyperwave functions: This library offers functions to access the Hyperwave information system or document database. Use of the library requires purchase of the enterprise Hyperwave Information Server.
Image and graphics functions: Contains over 50 functions to draw images and render true-type fonts using the GD library.
IMAP, POP3, and NNTP functions: Network-oriented functions that use these protocols to retrieve and process email messages and Internet news postings.
IRC gateway: Functions to access an Internet relay chat (IRC) gateway. IRC is an Internet-base chat room.
Lightweight Directory Access Protocol (LDAP) functions: Tools to connect to and retrieve information from servers that store hierarchical directory information using LDAP.
Mail functions: Really one function, mail( ), to send an email to a destination; discussed in Chapter 12.
Mathematical functions: Functions to do just about anything to a number, but not to very large numbers (for those, use the BCMath or the GMP library); for example, the mathematical library includes trigonometry, random number generation, logarithm, and exponential functions. Many of these are discussed in Chapter 2.
Modular Calendar Access Library (MCAL) functions: Tools to access and manage an event calendar, such as a desktop diary, that is managed the underlying MCAL C library.
Ming functions for Flash: Tools that allows creation of Flash format movies.
mnoGoSearch functions: Functions that access the freely available text search engine mnoGoSearch.
Network functions: Networking libraries for high- and low-level network communications; for example, includes functions to check if a domain name exists, and convert numeric IP addresses to domain names and vice versa. A short background on networking can be found in Appendix B
Output control: Manages the buffering of output by PHP, allowing control of the PHP script engine's output.
PDF functions: Functions that create and manipulate Adobe Portable Document Format (PDF) documents.
POSIX functions: Functions that get information about processes, users, and other system-oriented aspects of functions defined in the IEEE 1003.1 (POSIX.1) standards document.
Program execution functions: These are discussed briefly in the context of securing a web database application in Chapter 5.
Pspell functions: Spelling functions that can not only check spelling but also make suggestions for corrections.
GNU Re-code functions: Functions that convert strings from one character set to another.
Regular expressions: Along with the string functions, an introduction to regular expression functions is covered in Chapter 2. (We cover only the native regular expression library that conforms to the POSIX 1003.2 standard, not the Perl-compatible regular expressions functions).
Satellite CORBA client extension functions: Functions that can access and use CORBA distributed objects.
Semaphore and shared memory functions: Functions based on Unix System V semaphores that allow multiple users controlled access to shared resources such as global variables in shared memory.
Session management functions: These functions are covered in detail in Chapter 8; an alternate session management module is discussed in Appendix D.
SHMOP shared memory functions: These functions duplicate the functionality of the System V shared memory tools described previously, but without some of the overheads in creating and managing shared memory spaces.
Simple Network Management Protocol (SNMP) functions: Functions that interact with SNMP agents to find available objects and to set those objects.
SWF Shockwave Flash functions: Another function library to create and use Flash format movies, with overlapping functionality to the Ming library described earlier.
Socket functions: Low-level network libraries to open, send, and receive data, and close network sockets (sockets are often loosely referred to as ports, which are discussed in Appendix B). Has some overlap with the network library, but the socket library is more concerned with low-level networking tasks.
String functions: The popular string functions are discussed in detail in Chapter 2.
URL (Uniform Resource Locator) functions: Tools that encode and decode MIME base64 encoded data used in HTTP and email, that encode and decode special characters from URLs, and that parse a URL and return its components.
Variable functions: Variable functions for determining and setting types are covered in Chapter 2.
Web Distributed Data eXchange (WDDX) libraries: Tools that process the XML-like format used in the open standard WDDX format, a standard that permits interchange of data between web-scripting languages such as PHP, ASP, and ColdFusion. More information about the WDDX Software Development Kit (SDK) can be found at http://www.openwddx.org.
XSLT (eXtensible Stylesheet Language Transformations) functions: XSLT is a language for transforming XML documents from one standard XML format to another.
YAZ functions: A library that implements the Z39.50 protocol for information retrieval. Z39.50 can be used, for example, to issue a remote search on a text database and to return results in a standard format.
YP/NIS functions: Tools that manage network functions remotely, such as password files.
Zlib compression functions: A set of functions to read and write gzip files compressed using the algorithms of Jean-Loup Gailly and Mark Adler.

Several of these function libraries are immature and are dynamically being improved and changed. New libraries emerge every month. Some libraries are outdated, and the projects that underlie them are inactive. However, for most libraries, several successful installations and uses have been reported, and the latest details can usually be found along with example code at the PHP web site in the annotated manual, http://www.php.net/manual/.

We have omitted any discussion of wholly redundant libraries, those used exclusively with Microsoft Windows, very new libraries, unstable libraries, and those libraries that aren't used in web applications.