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| Name | Pylons for PHP Users |
|---|---|
| Space | Pylons CookBook |
| Page | Pylons for PHP Users |
| Section | Home |
| Version | 1.0 |
| Status | Draft |
| Reviewed | False |
| Author(s) | Mike Orr |
This page tries to explain Pylons in terms familar to PHP users, and describes the specific differences between PHP and Pylons. Or at least it will when it's finished.
High-level overview
A web framework at its core has one basic responsibility: produce an HTML page with HTTP headers according to the URL requested. Different frameworks do this in different ways:
- Apache has a simple dispatcher that maps a URL to a file in a directory, and sends that file.
- PHP is file-based. It relies on Apache's dispatcher to find a specific .php file, and then "executes" it to produce the HTML.
- Pylons handles the dispatching all on its own, via Routes (a Python library). Apache forwards the request to a running Pylons application. Pylons uses Routes to determine which method to call in which controller class, based on the URL. This method returns an HTML page as a string. Pylons adds the HTTP headers and forwards the result to Apache.
A template is like a form letter. "Dear Mr ___ : I am an accountant at __ Bank in Nigeria. The __ of __ was killed in a politically-motivated assasination and left behind $ __ in an untraceable account. I need your help to get this money out of the country away from corrupt ___ officials." A template engine fills in the blanks and produces a finished document. Mako, Genshi, Cheetah, and others are widely-used template engines in Pylons applications. PHP applications frequently use Smarty templates for the same purpose.
A key difference is that in PHP your code is embedded in the HTML page, whereas in Pylons your code produces your HTML. It can do that by returning a string, but most often it will invoke a template to produce the string.
Static (non-changing) files like images and stylesheets may be served directly by Apache outside Pylons, or by placing those files in a special "public" directory in your Pylons application.