Effective Django # 第三章 寫視圖

3.1 視圖基礎

任何可以調用的python都可以作為視圖。

3.2 generic & class based views

通用以及基于類的視圖

provide higher levels of abstraction and composability

also hide a lot of complexity, which can be confusing for the newcomer

luckily the documentation is much better with django 1.5

django 1.3 introduced class based views, which is what we’ll be focusing on here. class based views, or cbvs, can

eliminate a lot of boilerplate from your views, especially for things like an edit view where you want to take different

action on a get vs post. they give you a lot of power to compose functionality from pieces. the downside is that

this power comes with some added complexity.

3.3 class based views

基于類的視圖

the minimal class based view subclasses view (https://docs.djangoproject.com/en/1.5/ref/class-based-

views/base/#view) and implements methods for the http methods it supports. here’s the class-based version

of the minimalist “hello, world” view we previously wrote.

from django.http import httpresponse

from django.views.generic import view

class myview(view):

def get(self, request, *args, **kwargs):

return httpresponse("hello, world")

in a class based view, http methods map to class method names. in this case, we’ve defined a handler for get

requests with the get method. just like the function implementation, it takes request as its first argument, and

returns an http response.

permissive signatures

you may notice that it has a couple of extra arguments in its signature, compared to the view we saw previ-

ously, specifically *args and **kwargs. class based views were first introduced as a way to make django’s

“generic” views more flexible. that meant they were used in many different contexts, with potentially different

arguments extracted from the urls. as i’ve been writing class based views over the past year, i’ve continued to

write them with permissive signatures, as i’ve found they’re often useful in ways i didn’t initially expect.