A view function, or view for short, is a Python function that takes a\nweb request and returns a web response. This response can be the HTML contents\nof a web page, or a redirect, or a 404 error, or an XML document, or an image .\n. . or anything, really. The view itself contains whatever arbitrary logic is\nnecessary to return that response. This code can live anywhere you want, as long\nas it’s on your Python path. There’s no other requirement–no “magic,” so to\nspeak. For the sake of putting the code somewhere, the convention is to\nput views in a file called views.py, placed in your project or\napplication directory.
여기 현재 날짜와 시간을 HTML 문서로 반환하는 뷰가 있습니다:
\nfrom django.http import HttpResponse\nimport datetime\n\ndef current_datetime(request):\n now = datetime.datetime.now()\n html = "<html><body>It is now %s.</body></html>" % now\n return HttpResponse(html)\n한 줄씩 이 코드를 밟아나가 봅시다.
\n첫 번째로, django.http 모듈로부터 HttpResponse 클래스를, 파이썬의 datetime 라이브러리와 함께 임포트합니다.
다음으로 current_datetime 라는 함수를 정의합니다. 이것이 뷰 함수입니다. 각각의 뷰 함수는 HttpRequest 객체를 첫 인자로 가지며, 이 객체는 일반적으로 ``request``라는 이름입니다.
뷰 함수의 이름은 중요하지 않습니다. Django가 인식하도록 만들기 위해 특정한 방법으로 이름지을 필요는 없습니다. 여기서는 ``current_datetime``이라 부를 것이고, 이 이름이 하는 일을 분명하게 표현하기 때문입니다.
\n뷰는 생성된 응답을 담고 있는 HttpResponse 객체를 반환합니다. 각 뷰 함수는 HttpResponse 객체를 반환하는 역할을 합니다. (예외가 있지만, 나중에 알아보겠습니다)
따라서 이 뷰 함수는 현재 날짜와 시간을 포함한 HTML 페이지를 반환합니다. 특정한 URL에 이 뷰를 표시하고 싶다면, *URLconf*를 만들어야 합니다. 자세한 내용은 URL dispatcher 를 참조하세요.
\nDjango provides help for returning HTTP error codes. There are subclasses of\nHttpResponse for a number of common HTTP status codes\nother than 200 (which means “OK”). You can find the full list of available\nsubclasses in the request/response\ndocumentation. Return an instance of one of those subclasses instead of a\nnormal HttpResponse in order to signify an error. For\nexample:
from django.http import HttpResponse, HttpResponseNotFound\n\ndef my_view(request):\n # ...\n if foo:\n return HttpResponseNotFound('<h1>Page not found</h1>')\n else:\n return HttpResponse('<h1>Page was found</h1>')\nThere isn’t a specialized subclass for every possible HTTP response code,\nsince many of them aren’t going to be that common. However, as documented in\nthe HttpResponse documentation, you can also pass the\nHTTP status code into the constructor for HttpResponse\nto create a return class for any status code you like. For example:
from django.http import HttpResponse\n\ndef my_view(request):\n # ...\n\n # Return a "created" (201) response code.\n return HttpResponse(status=201)\nBecause 404 errors are by far the most common HTTP error, there’s an easier way\nto handle those errors.
\nHttp404 exceptionLink to this heading#When you return an error such as HttpResponseNotFound,\nyou’re responsible for defining the HTML of the resulting error page:
return HttpResponseNotFound('<h1>Page not found</h1>')\nFor convenience, and because it’s a good idea to have a consistent 404 error page\nacross your site, Django provides an Http404 exception. If you raise\nHttp404 at any point in a view function, Django will catch it and return the\nstandard error page for your application, along with an HTTP error code 404.
예시 용례:
\nfrom django.http import Http404\nfrom django.shortcuts import render\nfrom polls.models import Poll\n\ndef detail(request, poll_id):\n try:\n p = Poll.objects.get(pk=poll_id)\n except Poll.DoesNotExist:\n raise Http404("Poll does not exist")\n return render(request, 'polls/detail.html', {'poll': p})\nIn order to show customized HTML when Django returns a 404, you can create an\nHTML template named 404.html and place it in the top level of your\ntemplate tree. This template will then be served when DEBUG is set\nto False.
When DEBUG is True, you can provide a message to Http404 and\nit will appear in the standard 404 debug template. Use these messages for\ndebugging purposes; they generally aren’t suitable for use in a production 404\ntemplate.
The default error views in Django should suffice for most web applications,\nbut can easily be overridden if you need any custom behavior. Specify the\nhandlers as seen below in your URLconf (setting them anywhere else will have no\neffect).
\nThe page_not_found() view is overridden by\nhandler404:
handler404 = 'mysite.views.my_custom_page_not_found_view'\nThe server_error() view is overridden by\nhandler500:
handler500 = 'mysite.views.my_custom_error_view'\nThe permission_denied() view is overridden by\nhandler403:
handler403 = 'mysite.views.my_custom_permission_denied_view'\nThe bad_request() view is overridden by\nhandler400:
handler400 = 'mysite.views.my_custom_bad_request_view'\nTo test the response of a custom error handler, raise the appropriate exception\nin a test view. For example:
\nfrom django.core.exceptions import PermissionDenied\nfrom django.http import HttpResponse\nfrom django.test import SimpleTestCase, override_settings\nfrom django.urls import path\n\n\ndef response_error_handler(request, exception=None):\n return HttpResponse('Error handler content', status=403)\n\n\ndef permission_denied_view(request):\n raise PermissionDenied\n\n\nurlpatterns = [\n path('403/', permission_denied_view),\n]\n\nhandler403 = response_error_handler\n\n\n# ROOT_URLCONF must specify the module that contains handler403 = ...\n@override_settings(ROOT_URLCONF=__name__)\nclass CustomErrorHandlerTests(SimpleTestCase):\n\n def test_handler_renders_template_response(self):\n response = self.client.get('/403/')\n # Make assertions on the response here. For example:\n self.assertContains(response, 'Error handler content', status_code=403)\nAs well as being synchronous functions, views can also be asynchronous\n(“async”) functions, normally defined using Python’s async def syntax.\nDjango will automatically detect these and run them in an async context.\nHowever, you will need to use an async server based on ASGI to get their\nperformance benefits.
Here’s an example of an async view:
\nimport datetime\nfrom django.http import HttpResponse\n\nasync def current_datetime(request):\n now = datetime.datetime.now()\n html = '<html><body>It is now %s.</body></html>' % now\n return HttpResponse(html)\nYou can read more about Django’s async support, and how to best use async\nviews, in 비동기 지원.
\n