Request Handling

Apache's mod_rewrite will rewrite all requests (except those to a static directory) to the gate.py script. This script is quite small, all it does is create an instance of the Dispatcher class and call its .dispatch() method.

Upon dispatcher initialisation, the object initializes a requestfolder whose function is to provide abstracted access to respectively the request's GET, POST and URI variables. A sessionfolder object instance is also created to provide persistent variables to the framework.

The dispatcher solves the request by creating 'solution provider' instances of each 'solution provider' in a list.

• ManagementProvider
• TagProvider
• webobjectProvider
• LastResortProvider

The 'solution provider' instance looks at the request URL, and if it is able to provide a solution, it sets it .valid attribute, processes the request and provides a populated template via its attribute .template.

When a solutionprovider's .valid attribute is set after initializing it, the dispatcher breaks out of the loop and loads the page template. This template is the wrapper html skeleton and can read additional information of the solution provider if necessary, since the provider is passed to this template.

As you would expect, the page template shows the provider's .template by including it in its XML stream.

ProviderFoundation

All the solution providers inherit from this class, it provides an __init__ method that should be called from the actual provider class, this __init__ method does some preprocessing of the request argument and calls exposed methods if requested. It also provides default values for attributes like the title ("No Title!"), headers ([]) and exposed methods ([])

ManagementProvider

• /cms

Provides general methods like login, table status etc.

TagProvider

• /tags

Provides Tag management (create,drop) and webobject listings per tag.

webobjectProvider

• /objecttype (eg /articles, /photoalbums)
• /filename

Provides listings of all objects of a certain type, and handles requests of webobjects. For handling webobject requests, a group of classes that inherit from webobjectProvider is used. The model's webobject.byfilename() call will return an instance of a SQLObject, eg; article, picture. webobjectProvider will overload itself to eg; articleProvider.

LastResortProvider

This provider will always return a 404 page, if no other provider will answer the request.