Django Request and Response cycle – HttpRequest and HttpResponse Objects

Prerequisite – Views In Django | Python

Before we jump into using convenience methods that views come with, Let’s talk about Request and Response cycle. So when a Request happens to a Django server, a couple of things go on. One of them is Middleware.

Middleware
Middleware is like a middle ground between a request and response. It is like a window through which data passes. As in a window, light passes in and out of the house. Similarly when a request is made a request when made moves through middlewares to views and data is passed through middleware as a response.
Here are the default middlewares installed in Django.



middlewares-django-geeksforgeeks

You can add your middlewares. We will be discussing that in the next articles.

Request and Response Objects –

Django uses request and response objects to pass state through the system.

When a page is requested, Django creates an HttpRequest object that contains metadata about the request. Then Django loads the appropriate view, passing the HttpRequest as the first argument to the view function. Each view is responsible for returning an HttpResponse object.

HttpRequest and HttpResponse object Example

  • To explain these objects let’s create a view home as below in views.py
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    # importing HttResponse from library
    from django.http import HttpResponse
      
    def home(request):
        # request is handled using HttpResponse object
        return HttpResponse("Any kind of HTML Here")

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  • To handle the request let us map a URL to this view in urls.py
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    # importing view from views.py
    from .views import home
      
    urlpatterns = [
        path('', home),
      
    ]

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  • Now you can run the sever to see the following in browser
    HttpRequest-and-HttpResponse-Object-example

HttpRequest Attributes – Django

You can use following attributes with HttpRequest for advanced manipulation

Attribute Description
HttpRequest.scheme A string representing the scheme of the request (HTTP or HTTPs usually).
HttpRequest.body It returns the raw HTTP request body as a byte string.
HttpRequest.path It returns the full path to the requested page does not include the scheme or domain.
HttpRequest.path_info It shows path info portion of the path.
HttpRequest.method It shows the HTTP method used in the request.
HttpRequest.encoding It shows the current encoding used to decode form submission data.
HttpRequest.content_type It shows the MIME type of the request, parsed from the CONTENT_TYPE header.
HttpRequest.content_params It returns a dictionary of key/value parameters included in the CONTENT_TYPE header.
HttpRequest.GET It returns a dictionary-like object containing all given HTTP GET parameters.
HttpRequest.POST It is a dictionary-like object containing all given HTTP POST parameters.
HttpRequest.COOKIES It returns all cookies available.
HttpRequest.FILES It contains all uploaded files.
HttpRequest.META It shows all available Http headers.
HttpRequest.resolver_match It contains an instance of ResolverMatch representing the resolved URL.

HttpRequest Methods – Django

You can use following methods with HttpRequest for advanced manipulation

Attribute Description
HttpRequest.get_host() It returns the original host of the request.
HttpRequest.get_port() It returns the originating port of the request.
HttpRequest.get_full_path() It returns the path, plus an appended query string, if applicable.
HttpRequest.build_absolute_uri (location) It returns the absolute URI form of location.
HttpRequest.get_signed_cookie (key, default=RAISE_ERROR, salt=”, max_age=None) It returns a cookie value for a signed cookie, or raises a django.core.signing.BadSignature exception if the signature is no longer valid.
HttpRequest.is_secure() It returns True if the request is secure; that is, if it was made with HTTPS.
HttpRequest.is_ajax() It returns True if the request was made via an XMLHttpRequest.

HttpResponse Attributes – Django

You can use following attributes with HttpResponse for advanced manipulation

Attribute Description
HttpResponse.content A bytestring representing the content, encoded from a string if necessary.
HttpResponse.charset It is a string denoting the charset in which the response will be encoded.
HttpResponse.status_code It is an HTTP status code for the response.
HttpResponse.reason_phrase The HTTP reason phrase for the response.
HttpResponse.streaming It is false by default.
HttpResponse.closed It is True if the response has been closed.

HttpResponse Methods – Django

You can use following methods with HttpResponse for advanced manipulation

Method Description
HttpResponse.__init__(content=”, content_type=None, status=200, reason=None, charset=None) It is used to instantiate an HttpResponse object with the given page content and content type.
HttpResponse.__setitem__(header, value) It is used to set the given header name to the given value.
HttpResponse.__delitem__(header) It deletes the header with the given name.
HttpResponse.__getitem__(header) It returns the value for the given header name.
HttpResponse.has_header(header) It returns either True or False based on a case-insensitive check for a header with the provided name.
HttpResponse.setdefault(header, value) It is used to set default header.
HttpResponse.write(content) It is used to create response object of file-like object.
HttpResponse.flush() It is used to flush the response object.
HttpResponse.tell() This method makes an HttpResponse instance a file-like object.
HttpResponse.getvalue() It is used to get the value of HttpResponse.content.
HttpResponse.readable() This method is used to create stream-like object of HttpResponse class.
HttpResponse.seekable() It is used to make response object seekable.


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