Menulis tampilan

A view function, or view for short, is simply a Python function that takes a Web request and returns a Web response. This response can be the HTML contents of a Web page, or a redirect, or a 404 error, or an XML document, or an image . . . or anything, really. The view itself contains whatever arbitrary logic is necessary to return that response. This code can live anywhere you want, as long as it's on your Python path. There's no other requirement--no "magic," so to speak. For the sake of putting the code somewhere, the convention is to put views in a file called views.py, placed in your project or application directory.

Tampilan sederhana

Disini adalah tampilan yang mengembalikan data dan waktu saat ini, sebagai sebuah dokumen HTML:

from django.http import HttpResponse
import datetime

def current_datetime(request):
    now = datetime.datetime.now()
    html = "<html><body>It is now %s.</body></html>" % now
    return HttpResponse(html)

Mari kita melangkah melalui kode ini satu baris pada saat bersamaan:

  • Pertama, kami impor kelas HttpResponse dari modul django.http, bersama dengan pustaka datetime Python.

  • Next, we define a function called current_datetime. This is the view function. Each view function takes an HttpRequest object as its first parameter, which is typically named request.

    Note that the name of the view function doesn't matter; it doesn't have to be named in a certain way in order for Django to recognize it. We're calling it current_datetime here, because that name clearly indicates what it does.

  • The view returns an HttpResponse object that contains the generated response. Each view function is responsible for returning an HttpResponse object. (There are exceptions, but we'll get to those later.)

Zona Waktu Django

Django includes a TIME_ZONE setting that defaults to America/Chicago. This probably isn't where you live, so you might want to change it in your settings file.

Memetakan URL ke tampilan

So, to recap, this view function returns an HTML page that includes the current date and time. To display this view at a particular URL, you'll need to create a URLconf; see Pengirim URL for instructions.

Mengembalikan kesalahan

Returning HTTP error codes in Django is easy. There are subclasses of HttpResponse for a number of common HTTP status codes other than 200 (which means "OK"). You can find the full list of available subclasses in the request/response documentation. Just return an instance of one of those subclasses instead of a normal HttpResponse in order to signify an error. For example:

from django.http import HttpResponse, HttpResponseNotFound

def my_view(request):
    # ...
    if foo:
        return HttpResponseNotFound('<h1>Page not found</h1>')
    else:
        return HttpResponse('<h1>Page was found</h1>')

There isn't a specialized subclass for every possible HTTP response code, since many of them aren't going to be that common. However, as documented in the HttpResponse documentation, you can also pass the HTTP status code into the constructor for HttpResponse to create a return class for any status code you like. For example:

from django.http import HttpResponse

def my_view(request):
    # ...

    # Return a "created" (201) response code.
    return HttpResponse(status=201)

Karena kesalahan 404 sejauh ini paling umum kesalahan HTTP, ada sebuah cara paling mudah untuk menangani kesalahan-kesalahan tersebut.

Pengecualian Http404

class django.http.Http404

Ketika anda mengembalikan sebuah kesalahan seperti HttpResponseNotFound, anda bertanggung jawab untuk menentukan HTML dari menghasilkan halaman kesalahan:

return HttpResponseNotFound('<h1>Page not found</h1>')

For convenience, and because it's a good idea to have a consistent 404 error page across your site, Django provides an Http404 exception. If you raise Http404 at any point in a view function, Django will catch it and return the standard error page for your application, along with an HTTP error code 404.

Contoh penggunaan:

from django.http import Http404
from django.shortcuts import render
from polls.models import Poll

def detail(request, poll_id):
    try:
        p = Poll.objects.get(pk=poll_id)
    except Poll.DoesNotExist:
        raise Http404("Poll does not exist")
    return render(request, 'polls/detail.html', {'poll': p})

Untuk menampilkan HTML disesuaikan ketika Django mengembalikan sebuah 404, anda dapat membuat sebuah cetakan HTML bernama 404.html dan menempatkan itu dalam tingkat atas dari pohon cetakan anda. Cetakan anda kemudian akan dilayani ketika DEBUG disetel menjadi False.

Ketika DEBUG adalah True, anda dapat menyediakan sebauh pesan pada Http404 dan itu akan muncul dalam cetakan mencari kesalahan 404 standar. Gunakan pesan-pesan ini untuk tujuan mencari kesalahan; mereka umumnya tidak cocok untuk digunakan dalam produksi cetakan 404.

Menyesuaikan tampilan kesalahan

The default error views in Django should suffice for most Web applications, but can easily be overridden if you need any custom behavior. Simply specify the handlers as seen below in your URLconf (setting them anywhere else will have no effect).

Tampilan page_not_found() ditimpa oleh handler404:

handler404 = 'mysite.views.my_custom_page_not_found_view'

Tampilan server_error() ditimpa oleh handler500:

handler500 = 'mysite.views.my_custom_error_view'

Tampilan permission_denied() ditimpa oleh handler403:

handler403 = 'mysite.views.my_custom_permission_denied_view'

Tampilan bad_request() ditimpa oleh handler400:

handler400 = 'mysite.views.my_custom_bad_request_view'

lihat juga

Gunakan pengaturan CSRF_FAILURE_VIEW utnuk menimpa tampilan kesalahan CSRF.

Pengirim URL
View decorators
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