Table of Contents
This document serves as an intro to TurboGears for those migrating from CakePHP (and possibly other PHP frameworks). We will assume some familiarity with the Python language, and will try to stick to outlining the core differences between the frameworks rather than the languages (quite beyond the scope of this document).
Of course, the largest difference between CakePHP and TurboGears is the core language. However, from a technical standpoint, both are quite similar: Both are open source, both have an active community, and both provide a rich component set.
|Framework||Language||License||Started||Deployment Options||MVC||MVC Push/Pull||i18n & l10n|
|CakePHP||PHP||MIT||2005||Apache, FastCGI, etc.||Yes||Push||Yes|
|TurboGears||Python||MIT/LGPL||2005||paster, Apache (mod_wsgi or mod_proxy)||Yes||Push||Yes|
Feature and component wise, both frameworks provide advanced functionality such as a rich ORM, a tight security framework, and an easy to use forms creation & validation framework:
|ORM:||Active Record Pattern||SQLAlchemy (Data Mapper Pattern)|
|Testing Framework:||Based on SimpleTest||nose|
|Security Framework:||Security component||repoze.who & repoze.what|
|Forms Framework:||Form helper||tw.forms & formencode|
|DB Migration Framework:||SchemaShell||sqlalchemy-migrate|
|Template Framework:||PHP files||Multiple |
|Ajax:||Prototype & script.aculo.us||toscawidgets or roll your own |
|||TurboGears supports Genshi (default), Mako, and Jinja2 out of the box. See the alternate templates page for more information.|
|app/vendors||n/a – use easy_install packagename|
See this image for more information.
By default TurboGears is setup with one default route which goes to your RootController. This means you typically don’t have to think about routes at all, and gives you great design flexibility.
However, advanced routing is available if needed. See Routes Integration in TG2 for more information.
In CakePHP (and many other PHP web frameworks) you are expected to have a separate controller file & class for each :controller route. The methods of the controller class become the :action routes, with the method arguments being the :id.
In TurboGears, the philosiphy is similar with a bit of added flexability. As was mentioned in the previous section, the default routing in TurboGears is to the RootController class in myapp/controllers/root.py. From RootController, you are free to define “sub-controllers” and methods however you like. A typical setup might look like this:
# initial imports edited out # this import loads our "sub-controller" from myapp.controllers.about import AboutController class RootController(BaseController): # the line below instructs the "about" route (http://www.example.com/about/) to # load the index method of the AboutController about = AboutController() # the next few lines handle the loading of the "root" route (http://www.example.com/) @expose('myapp.templates.index') # loads the index template def index(self): # defines the "index" action return dict(page='index') # the 'page' variable is available in our template # you could just as easily specify another "controller" route (like we did with 'about') # by defining another method in this controller (becomes http://www.example.com/contact/) @expose() # no template needed (returning a string) def contact(self): return 'email@example.com' # simply prints firstname.lastname@example.org
This is what the AboutController file might look like:
class AboutController(BaseController): # the index action (http://www.example.com/about/) @expose('myapp.templates.about') def index(self): return dict(page='about')
Although these attributes play a major part in CakePHP classes, TurboGears has no need for this type of class attribute definition. To use a “component” or “helper” package in your class you would simply import packagename. For your models you would simply from myapp.model import ModelClassName.
CakePHP has a few special controller methods that deal with things like passing objects to a template, rendering templates, etc. Below is a list of these methods, and TurboGears’ equivalent:
|set()||tmpl_context or passed in return dict()|
|redirect()||from tg import redirect|
|flash()||from tg import flash|
The “batteries included” nature of Python (and therefore TurboGears) means that you have a lot of packages available right at your fingertips. Aside from familiarizing yourself with Python’s standard library, it is also a good idea to become acquainted with TurboGears’ module library.
|ACL, Auth & Security||repoze.who and repoze.what|
|Cookie||from tg import response, response.set_cookie() & from tg import request, request.cookies|
|Session||from tg import session|
TurboGears uses a high-performance enterprise-level SQL toolkit and ORM named SQLAlchemy.
Whereas PHP itself acts as CakePHP’s template language, TurboGears has a number of templating languages available. The most popular choices are Genshi (a pure XML-based template language) and Mako (non-XML, but much faster than Genshi).
As we saw earlier in TG’s equivalent Controller Methods, data is typically passed from the controller to the view by using the special tmpl_context object, or by defining dictionary values in the controller method’s return.
Helpers are managed in the mypackage/lib/helpers.py file and are typically accessed in your template through the h object. TurboGears ships with several built-in helpers (see the webhelpers page), but Python’s modular nature makes it very easy to add helpers to your project. Usually all you have to do is easy_install packagename and then at the top of your helpers.py file put import packagename as mynewhelper. You can then access your new helper in your view by using h.mynewhelper.
As we just mentioned, TurboGears makes it very easy to “plug & play” helpers. Below is a list of CakePHP’s built-in helpers, with the TurboGears equivalent that is typically used:
|Ajax||toscawidgets or roll your own |
|Form||tw.forms and/or sprox|
|XML||ElementTree or lxml|
Apart from a project quickstart, TurboGears tries to avoid generating code for you. We are of the opinion that it is easier to build pages from the ground up than to tweak code that is generated from a framework’s “best-guess” about your project.
Having said that, there are a couple of modules and extensions that can help you start interacting with your models right away: