Often a direct file descriptor will be less CPU- and memory-intensive than calling through the streams layer; however, it places all the work of implementing a particular protocol on you as the extension writer. By hooking into the streams layer, your extension code can transparently use any of the built-in stream wrappers such as HTTP, FTP, and their SSL-enabled counterparts, as well as the gzip and bzip2 compression wrappers. By including certain PEAR or PECL modules, your code also has access to other protocols such as SSH2, WebDav, and even Gopher!
This chapter will introduce the basic API for working with streams from the internals. Later on, in Chapter 16, "Diverting the Stream," you'll take a look at more advanced concepts like applying filters and using context options and parameters.
The PHP Life Cycle
Variables from the Inside Out
Setting Up a Build Environment
Your First Extension
Working with Arrays and HashTables
The Resource Data Type
Startup, Shutdown, and a Few Points in Between
Diverting the Stream
Configuration and Linking
Setting Up a Host Environment
Appendix A. A Zend API Reference
Appendix B. PHPAPI
Appendix C. Extending and Embedding Cookbook
Appendix D. Additional Resources