Programming Python, Second Edition

Python Server Pages

Though still somewhat new at this writing, Python Server Pages (PSP) is a server-side technology that embeds JPython code inside HTML. PSP is a Python-based answer to other server-side embedded scripting approaches.

The PSP scripting engine works much like Microsoft’s Active Server Pages (ASP, described earlier) and Sun’s Java Server Pages ( JSP) specification. At the risk of pushing the acronym tolerance envelope, PSP has also been compared to PHP, a server-side scripting language embedded in HTML. All of these systems, including PSP, embed scripts in HTML and run them on the server to generate the response stream sent back to the browser on the client; scripts interact with an exposed object model API to get their work done. PSP is written in pure Java, however, and so is portable to a wide variety of platforms (ASP applications can be run only on Microsoft platforms).

PSP uses JPython as its scripting language, reportedly a vastly more appropriate choice for scripting web sites than the Java language used in Java Server Pages. Since JPython code is embedded under PSP, scripts have access to the large number of Python and JPython tools and add-ons from within PSPs. In addition, scripts may access all Java libraries, thanks to JPython’s Java integration support.

We can’t cover PSP in detail here; but for a quick look, Example 15-18, adapted from an example in the PSP documentation, illustrates the structure of PSPs.

Example 15-18. PP2E\Internet\Other\hello.psp ...