mod_perl Developer's Cookbook

mod_perl is a unique piece of software that wholly integrates the power of Perl with the flexibility and stability of the Apache Web server. With mod_perl, developers can harness the power of the full Apache API and develop Web applications quickly and without sacrificing performance.

The mod_perl Developer's Cookbook teaches programming with the mod_perl API by example. The book takes developers from the basics of mod_perl to the development advanced Web applications. Developers will learn tricks, solutions, and mod_perl idioms gleaned from the authors' experience as developers and expert users of mod_perl.

Geoffrey Young is a frequent contributor to the mod_perl community and has written scores of mod_perl handlers, the most useful of which can be found on CPAN.

Paul Lindner manages, designs, and implements mod_perl applications at Critical Path. He is a long-time Internet and open-source developer, and was one of the founders of the Internet Gopher at the University of Minnesota.

Randy Kobes is a professor of physics at the University of Winnipeg who conducts research on chaos and fractals. He used mod_perl to establish a search engine for CPAN.

Developers searching for solutions to specific problems can use the mod_perl Developer's Cookbook as a

collection of ready-made recipes to be understood and applied to their problems.

Developers searching for continuing mod_perl education will find the book's recipes to be enlightening, well-researched, and broadly applicable.

—Ken Williams

Geoffrey Young is a frequent contributor to the mod_perl community and has written scores of mod_perl handlers, the most useful of which can be found on CPAN. When not programming or writing, he is busy spending time with his wife and daughter, slowly rebuilding their house a room at a time.

Paul Lindner manages, designs, and implements mod_perl applications at Critical Path. He is a long-time Internet and open-source developer, and was one of the founders of the Internet Gopher at the University of Minnesota. Recently he has developed large mission-critical Web systems for the International Telecommunications Union, the United Nations Office for the High Commissioner for Human Rights, Red Hat, and Critical Path.

Randy Kobes is a professor of physics at the University of Winnipeg in Canada who conducts research on chaos and fractals. He used mod_perl to establish a search engine for the Comprehensive Perl Archive Network.

Introduction.

I. INSTALLATION AND CONFIGURATION. 1. Installing mod_perl.

Introduction. Unix Binary Installation. Windows Binary Installation. Mac OS X Binary Installation. Building mod_perl on Unix. Building mod_perl on Windows. Building mod_perl on Mac OS X. Building mod_perl as a Shared Library. Testing Your Installation. Changing Apache Installation Directories. Adding mod_perl to an Existing Apache Server. Reusing Configuration Directives. Re-Creating a mod_perl Installation. Distributing mod_perl to Many Machines. Inspecting an Existing Server. Installing Apache Modules from CPAN. Following mod_perl Development. Beyond Simple CVS. Building mod_perl with Different perls. 2. Configuring mod_perl.

Introduction. Migrating Legacy CGI Scripts. Using Apache::Registry. The startup.pl Script. Sharing Script Namespace Under Apache::Registry. Pre-Caching Apache::Registry Scripts. Populating CGI Environment Variables. Setting Other Environment Variables. Using Perl Switches. BEGIN and END Blocks in startup.pl. Maintaining Your Own Libraries. Persistent Database Connections. Pre-Spawning Database Connections. Nonpersistent Database Connections in a Persistent Environment. Setting mod_perl-Only Variables. Setting Complex mod_perl Variables. Configuring Apache with Sections. Preserving Order in Sections. Using Command-Line Switches. Running Dual Servers. Using mod_proxy to Direct Requests to a mod_perl Server. Using mod_proxy_add_forward.

II. THE MOD_PERL API. 3. The Apache Request Object.

Introduction. The Apache Request Object. The HTTP Request Message. The Client Request. Accessing Client Request Headers. Accessing HTML Form Fields. Reading POSTed Data Manually. Manipulating Cookies. Handling File Uploads. Setting Server Response Headers. Controlling Caching Behavior. Sending Server Response Headers. Setting the Response Status. Setting Error Headers. Manipulating Headers with Multiple Like Fields. Using Subrequests. Setting Headers for Subrequests. Short-Circuiting Subrequests. Getting or Setting the Request Method. Accessing the Request Object from XS. 4. Communicating with the Apache Server.

Introduction. Accessing the Apache::Server Object. Simulating IfModule and IfDefine Directives. Accessing ServerRoot and DocumentRoot. Writing to the Apache Error Log. Accessing the Apache ErrorLog Directive. Controlling the LogLevel. Accessing the Apache::Connection Object. Remote IP Addresses and Hosts. Detecting a Broken Connection. Terminating an Apache Child Process. 5. URI Manipulation.

Introduction. Capturing the Request URI. Determining the URI . Altering the Request URI. Constructing a New URI. Escaping Special Characters Within a URI. Using the URI to Force a MIME Type. Capturing Content from a Subrequest. Using Apache::Util Outside mod_perl. 6. File Handling.

Introduction. Creating Filehandles. Creating Temporary Files. Sending an Entire File. Reading Files into Variables. Getting Information About the Requested File. Working with Conditional Headers. Byteserving and Range Requests. Manipulating Date-Based Headers Directly. Flushing the Print Buffers. Redirecting Output Filehandles. 7. Creating Handlers.

Introduction. Creating a mod_perl Handler. Basic Handler Configuration. Adding Handlers On-the-Fly. Preparing a Module for Release. Creating a Release Tarball. Creating a Binary PPM Distribution. Writing a Live Server Test Suite. Adding Custom Configuration Directives. Expanding Custom Directive Prototypes. Merging Custom Configuration Directives. Overriding Core Directives. Adding Unique Server Tokens. Releasing a Module to CPAN. 8. Interacting with Handlers.

Introduction. Recognizing Handler Changes. Sharing Data Within a Child Process. Creating a Shared Memory Cache. Maintaining State. Using Internal Redirects. Writing Custom ErrorDocuments. Resetting Default ErrorDocuments. Manipulating Stacked Perl Handlers. Manipulating Stacked C Handlers. Accessing the Environment. Sharing Data Between Different Phases. Determining the Current Request Phase. Reading a Perl Module's Configuration Data. Reading a C Module's Configuration Data. 9. Tuning Apache and mod_perl.

Introduction. Gathering Basic Server Information. Gathering Systemwide Memory Usage Data. Gathering Basic Server Memory Data. Gathering Detailed Server Memory Data. Gathering Memory Data for Perl Modules. Reducing Module Overhead. Reducing Overall Memory Consumption. Increasing Shared Memory. Coarse Process Tuning Using Apache Directives. Limiting Process Growth. Stopping Runaway Processes. Profiling Handlers. Finding Performance Bottlenecks. Server Performance Tuning. Using Apache as a Reverse Proxy Server. Using the Perl Debugger with mod_perl. Debugging Apache::Registry Scripts. Reducing Debug Overhead. Debugging Segmentation Faults. 10. Object-Oriented mod_perl.

Introduction. Class and Object Creation. Method Inheritance. Creating Method Handlers. Using Method Handlers. Subclassing the Apache Class. Subclassing the Apache Class Using XS. Subclassing Apache::Registry. Subclassing Apache::Request.

III. PROGRAMMING THE APACHE LIFECYCLE. 11. The PerlInitHandler.

Introduction. Processing Every Request. Processing Every Request to a . Timing the Request. Interrupting the Request Cycle. 12. The PerlTransHandler.

Introduction. Redirecting Requests to favicon.ico. Protecting Name-Based Virtual Hosts. Storing Sessions in URLs. Sharing a Common DocumentRoot. Controlling Apache's Built-In Proxy. Reducing stat() Calls. 13. The PerlAccessHandler, PerlAuthenHandler, and PerlAuthzHandler.

Introduction. Simple Access Control. Restricting Access to Greedy Clients. Basic Authentication. Setting User Credentials. Conditional Authentication. User Authorization. Writing Your Own Authentication Mechanism. Using Digest Authentication. 14. The PerlTypeHandler and PerlFixupHandler.

Introduction. Resetting the Default Apache Handler. Selecting PerlHandlers Based on File Extensions. Customizing Request MIME Type and Content Handler. Overriding Default MIME Types. Using Apache as a Caching Engine. 15. The PerlHandler.

Introduction. A Basic PerlHandler. Managing Multiple PerlHandlers. Sending Mail. Filtered Content Generation. Preventing Cross-Site Scripting Attacks. Using Text::Template. Using HTML::Template. Using Apache::ASP. Using Template Toolkit. Using HTML::Embperl. Using HTML::Mason. Generating XML Documents. Generating Generic XML Content. Using XML and XSLT Stylesheets. Using AxKit. Creating a SOAP Server. 16. The PerlLogHandler and PerlCleanupHandler.

Introduction. Logging to a Database. Logging to a Flat File. Altering the Request-Line. Logging Nonstandard Data. Conditional Logging. Intercepting Errors. 17. The PerlChildInitHandler, PerlChildExitHandler, PerlRestartHandler, and PerlDispatchHandler.

Introduction. Passing Configurations to Code Outside of a Request. Running Code When Apache Restarts. Preloading Configuration Data. Reloading Registry Scripts in the Parent Process. Identifying Apache Children. Preconnecting to Data Sources. Tracking Perl Module Usage. Overriding Handlers Using a PerlDispatchHandler. Appendix A. Available mod_perl Hooks and Build Flags.

mod_perl Hooks. mod_perl Build Options. Appendix B. Available Constants.

Handler Return Codes. HTTP Return Codes. Directive Handler Constants. Logging Constants. Server Constants. Appendix C. mod_perl Resources.

Online Resources. Books. Index.