Django Request and Response Loop — HttpRequest and HttpResponse objects

Python Methods and Functions

Before we get into using the convenience methods that come with views, let`s talk about the request and response loop. So when there is a request to the Django server, several things happen. One of them is Middleware.

Middleware
Middleware — it is a cross between a request and a response. It`s like a window through which data flows. As in the window, light comes in and out of the house. Similarly, when a request is made, the request, when made, travels through the middleware to the views, and the data is passed through the middleware as a response. 
Here is the default middleware installed in Django.

You can add your middleware. We`ll discuss this in future articles.

Request and response objects —

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

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

Example HttpRequest and HttpResponse objects

  • To explain these objects, let`s create a view house as shown below in views.py

    # import HttResponse from library

    from django.http import HttpResponse

     

    def home (request):

    # the request is processed using the HttpResponse object

    return HttpResponse ( "Any kind of HTML Her e " )

  • To process the request, let`s map the URL to this view in urls.py

    # import view from views.py

    from . views import home

     

    urlpatterns = [

    path (``, home),

      
    ]

  • Now you can start the server to see the following in your browser

HttpRequest Attributes — Django

You can use the 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 the 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 the 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 the 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.





Get Solution for free from DataCamp guru