non-Webware HTML output — Cheetah3 - The Python-Powered Template Engine

# non-Webware HTML output

Cheetah can be used with all types of HTML output, not just with Webware.

## Static HTML Pages

Some sites like Linux Gazette (http://www.linuxgazette.com/) require completely static pages because they are mirrored on servers running completely different software from the main site. Even dynamic sites may have one or two pages that are static for whatever reason, and the site administrator may wish to generate those pages from Cheetah templates.

There’s nothing special here. Just create your templates as usual. Then compile and fill them whenever the template definition changes, and fill them again whenever the placeholder values change. You may need an extra step to copy the .html files to their final location. A Makefile (chapter tips.Makefile) can help encapsulate these steps.

## CGI scripts

Unlike Webware servlets, which don’t have to worry about the HTTP headers, CGI scripts must emit their own headers. To make a template CGI aware, add this at the top:

    #extends Cheetah.Tools.CGITemplate
    #implements respond
    $cgiHeaders#slurp

Or if your template is inheriting from a Python class:

    #extends MyPythonClass
    #implements respond
    $cgiHeaders#slurp

A sample Python class:

    from Cheetah.Tools import CGITemplate
    class MyPythonClass(CGITemplate):
        def cgiHeadersHook(self):
            return "Content-Type: text/html; charset=koi8-r\n\n"

Compile the template as usual, put the .py template module in your cgi-bin directory and give it execute permission. {.cgiHeaders()} is a “smart” method that outputs the headers if the module is called as a CGI script, or outputs nothing if not. Being “called as a CGI script” means the environmental variable {REQUEST_METHOD} exists and {self.isControlledByWebKit} is false. If you don’t agree with that definition, override {.isCgi()} and provide your own.

The default header is a simple `Content-type: text/html\n\n`, which works with all CGI scripts. If you want to customize the headers (e.g., to specify the character set), override {.cgiHeadersHook()} and return a string containing all the headers. Don’t forget to include the extra newline at the end of the string: the HTTP protocol requires this empty line to mark the end of the headers.

To read GET/POST variables from form input, use the {.webInput()} method (section webware.webInput), or extract them yourself using Python’s {cgi} module or your own function. Although {.webInput()} was originally written for Webware servlets, it now handles CGI scripts too. There are a couple behavioral differences between CGI scripts and Webware servlets regarding input variables:

1. CGI scripts, using Python’s {cgi} module, believe {REQUEST_METHOD} and recognize { either} GET variables { or} POST variables, not both. Webware servlets, doing additional processing, ignore {REQUEST_METHOD} and recognize both, like PHP does.

2. Webware servlets can ask for cookies or session variables instead of GET/POST variables, by passing the argument {src=’c’} or {src=’s’}. CGI scripts get a {RuntimeError} if they try to do this.

If you keep your .tmpl files in the same directory as your CGI scripts, make sure they don’t have execute permission. Apache at least refuses to serve files in a {ScriptAlias} directory that don’t have execute permission.