Django >= 3.1 and is_ajax - django

HttpRequest.is_ajax() is deprecated starting with version 3.1.
I want to return html if the page is requested from a browser and as JsonResponse if called from javascript or programmatically.
I am seeking guidance on how to do that.
https://docs.djangoproject.com/en/3.1/ref/request-response/#django.http.HttpRequest.is_ajax

Check HTTP_X_REQUESTED_WITH header
def sample_view(request):
is_ajax = request.META.get('HTTP_X_REQUESTED_WITH') == 'XMLHttpRequest'
From the Release Notes of 3.1
The HttpRequest.is_ajax() method is deprecated as it relied on a jQuery-specific way of signifying AJAX calls, while current usage tends to use the JavaScript Fetch API. Depending on your use case, you can either write your own AJAX detection method, or use the new HttpRequest.accepts() method if your code depends on the client Accept HTTP header.

Funny thing -- the quoted deprecation blurb only gets you halfway there. There's no indication of how you "use the new HttpRequest.accepts method" to replace HttpRequest.is_ajax -- not in the deprecation text, nor the documentation, nor the release notes.
So, here it is: if request.accepts("application/json")
(At least that's what worked for me.)

Instead of:
if request.is_ajax():
Helped me:
if request.headers.get('x-requested-with') == 'XMLHttpRequest':

have you tried to check HttpRequest.headers?
HttpRequest.is_ajax() depends on HTTP_X_REQUESTED_WITH header.
so you can check this header, if it is true it would be AJAX other wise it would be a request from a browser.
HttpRequest.headers['HTTP_X_REQUESTED_WITH']

I did what arakkal-abu said but I also added
'X-Requested-With' header with the same value
ie. 'XMLHttpRequest'
to my request and it worked

Make sure to import this at the top
import re
from django.http import JsonResponse
from django.utils.translation import gettext_lazy as _
from django.conf.urls import handler404
You can have this inside your function/method to determine if from browser or ajax call
requested_html = re.search(r'^text/html', request.META.get('HTTP_ACCEPT'))
if requested_html:
# requested from browser, do as per your wish
# ajax call. Returning as per wish
return JsonResponse({
'detail': _('Requested API URL not found')
}, status=404, safe=False)
Explanation
If you request to load a page from a browser, you would see in the network tab under the requested headers of that request, text/html is at the beginning of requested headers.
However, if you are making an ajax call from the browser, the requested headers has */* in the beginning. If you attach
Accept: application/json
in the header, then requested headers become this
From this, you can understand how the accept header is different in these cases.

Simply check the Content-Type header.
is_ajax = request.META.get("CONTENT_TYPE") == "application/json"
if is_ajax:
do_stuff()

Combining the suggestions works for our use cases...
def is_ajax(request: django.http.request.HttpRequest) -> bool:
"""
https://stackoverflow.com/questions/63629935
"""
return (
request.headers.get('x-requested-with') == 'XMLHttpRequest'
or request.accepts("application/json")
)
And then replace all instances of request.is_ajax() with is_ajax(request).

Related

How to follow Django redirect using django-pytest?

In setting up a ArchiveIndexView in Django I am able to successfully display a list of items in a model by navigating to the page myself.
When going to write the test in pytest to verify navigating to the page "checklist_GTD/archive/" succeeds, the test fails with the message:
> assert response.status_code == 200
E assert 301 == 200
E + where 301 = <HttpResponsePermanentRedirect status_code=301, "text/html; charset=utf-8", url="/checklist_GTD/archive/">.status_code
test_archive.py:4: AssertionError
I understand there is a way to follow the request to get the final status_code. Can someone help me with how this done in pytest-django, similar to this question? The documentation on pytest-django does not have anything on redirects. Thanks.
pytest-django provides both an unauthenticated client and a logged-in admin_client as fixtures. Really simplifies this sort of thing. Assuming for the moment that you're using admin_client because you just want to test the redirect as easily as possible, without having to log in manually:
def test_something(admin_client):
response = admin_client.get(url, follow=True)
assert response.status_code == 200
If you want to log in a standard user:
def test_something(client):
# Create user here, then:
client.login(username="foo", password="bar")
response = client.get(url, follow=True)
assert response.status_code == 200
By using follow=True in either of these, the response.status_code will equal the return code of the page after the redirect, rather than the access to the original URL. Therefore, it should resolve to 200, not 301.
I think it's not documented in pytest-django because the option is inherited from the Django test client it subclasses from (making requests).
UPDATE:
I'm getting downvoted into oblivion but I still think my answer is better so let me explain.
I still think there is a problem with Shacker's answer, where you can set follow=True and get a response code of 200 but not at the URL you expect. For example, you could get redirected unexpectedly to the login page, follow and get a response code of 200.
I understand that I asked a question on how to accomplish something with pytest and the reason I'm getting downvoted is because I provided an answer using Django's built-in TestCase class. However, the correct answer for the test is/was more important to me at the time than exclusively using pytest. As noted below, my answer still works with pytest's test discovery so I think the answer is still valid. After all, pytest is built upon Django's built-in TestCase. And my answer asserts the response code of 200 came from where I expected it to come from.
The best solution would be to modify pytest to include the expected_url as a parameter. If anyone is up for doing this I think it would be a big improvement. Thanks for reading.
ORIGINAL CONTENT:
Answering my own question here. I decided to include final expected URL using the built-in Django testing framework's assertRedirects and verify that it (1) gets redirected initially with 302 response and (2) eventually succeeds with a code 200 at the expected URL.
from django.test import TestCase, Client
def test_pytest_works():
assert 1==1
class Test(TestCase):
def test_redirect(self):
client = Client()
response = client.get("/checklist_GTD/archive/")
self.assertRedirects(response, "/expected_redirect/url", 302, 200)
Hat tip to #tdsymonds for pointing me in the right direction. I appreciated Shacker's answer but I have seen in some scenarios the redirect result being 200 when the page is redirected to an undesirable URL. With the solution above I am able to enforce the redirect URL, which pytest-django does not currently support.
Please note: This answer is compliant with the auto-discover feature of pytest-django and is thus not incompatible (it will auto-discover both pytest-django and Django TestCase tests).

When to use django shortcut functions

When would you want to create a response object and return it from a view such as
return HttpResponse( ... )
instead of using a shortcut function like render() or redirect()?
HttpResponse can only be passed in a HTML string and HTTP headers.
HttpResponseRedirect expects redirect URL string.
render() can be more fine tuned for auto-generated responses (via templates and contexts). It builds the proper HttpResponse object for you.
Likewise redirect() can automatically resolve URLs of your views (and even models!) and return a HttpResponseRedirect object.
For more specific information you should refer to the official django documentation.
When you make your backend at Django and let the front end be elsewhere (may be Android/iOS app) then, You can sometimes return strings like "Success" using HttpResponse().

Can I pass non-URL definition view keyword to a view function when redirecting?

NoReverseMatch at /natrium/script/4c55be7f74312bfd435e4f672e83f44374a046a6aa08729aad6b0b1ab84a8274/
Reverse for 'run_details' with arguments '()' and keyword arguments '{'script_text': u'print "happy"', 'run_id': '6b2f9127071968c099673254fb3efbaf'}' not found.
This is an excerpt of my views.py
run_id = new_run.run_id
if not run_id:
raise AssertionError("bad run id")
# I tried with args=[run_id, clean['script_text']] too
return HttpResponseRedirect(reverse('run_details', kwargs={'run_id':run_id, 'script_text':clean['script_text']}))
which in turns calling this view function
def run_details(request, run_id, script_text):
"""
Displays the details of a given run.
"""
run = Run(run_id)
run.update(request.user)
codebundle = CodeBundle(run.cbid)
codebundle.update(request.user)
return render_response(request, "graphyte/runs/run_script.html",
{'run':run, 'codebundle':codebundle, 'files':run.artifacts, 'bundle':codebundle,
'source_code': script_text
})
Now this is my urls.py. The actual redirect views is in another app (kinda insane, but whatever...).
urlpatterns = patterns("webclient.apps.codebundles.views",
# many.....
url(r"^cb/newfolder/$", 'codebundle_newfolder', name="codebundle_newfolder"),
)
urlpatterns += patterns('webclient.apps.runs.views',
url(r"^run_details/(?P<run_id>\w+)/$", 'run_details', name="run_details"),)
This is getting really nasty for the last three hours. I am not sure what's going on. Can someone help me debug this?
Thanks.
The original plan did not have script_text, and I used args=['run_id'] only. It works. In other words, remove script_text from the two views everything will work.
EDIT
Sorry for the confusion. Script text is just a context variable that I need to pass to the reverse destination, and from there I render my template. The URLs should only display the run_id.
No, you can't really pass an 'extra keyword' to the view function when redirecting. I'll try to explain why.
When you return HttpResponseRedirect, Django returns a response with a 302 status code, and the new location.
HTTP/1.1 302 Found
Location: http://www.example.com/new-url/
Your browser will then usually fetch the new url, but that's a separate request. If your view needs a keyword, it needs to be included in that response somehow, unless you store state in the session. Your two options are
Include the extra keyword in the url:
http://www.example.com/new-url/keyword-value/
Include the extra keyword as a GET parameter
http://www.example.com/new-url/?keyword=keyword-value.
Then in your view, grab the keyword with keyword=request.GET['keyword']. Note that the keyword is no longer a kwarg in the view signature.
A third approach is to stick the keyword into the session before you redirect, then grab it out the session in the redirected view. I would advise against doing this because it's stateful and can cause odd results when users refresh pages etc.
Your run_details url doesn't accept a kwarg named script_text at all -- remove that from your reverse kwargs.

Determine the requested content type?

I'd like to write a Django view which serves out variant content based on what's requested. For example, for "text/xml", serve XML, for "text/json", serve JSON, etc. Is there a way to determine this from a request object? Something like this would be awesome:
def process(request):
if request.type == "text/xml":
pass
elif request.type == "text/json":
pass
else:
pass
Is there a property on HttpRequest for this?
'Content-Type' header indicates media type send in the HTTP request. This is used for requests that have a content (POST, PUT).
'Content-Type' should not be used to indicate preferred response format, 'Accept' header serves this purpose. To access it in Django use: HttpRequest.META.get('HTTP_ACCEPT')
See more detailed description of these headers
HttpRequest.META, more specifically HttpRequest.META.get('HTTP_ACCEPT') — and not HttpRequest.META.get('CONTENT_TYPE') as mentioned earlier
As said in other answers, this information is located in the Accept request header. Available in the request as HttpRequest.META['HTTP_ACCEPT'].
However there is no only one requested content type, and this header often is a list of accepted/preferred content types. This list might be a bit annoying to exploit properly. Here is a function that does the job:
import re
def get_accepted_content_types(request):
def qualify(x):
parts = x.split(';', 1)
if len(parts) == 2:
match = re.match(r'(^|;)q=(0(\.\d{,3})?|1(\.0{,3})?)(;|$)',
parts[1])
if match:
return parts[0], float(match.group(2))
return parts[0], 1
raw_content_types = request.META.get('HTTP_ACCEPT', '*/*').split(',')
qualified_content_types = map(qualify, raw_content_types)
return (x[0] for x in sorted(qualified_content_types,
key=lambda x: x[1], reverse=True))
For instance, if request.META['HTTP_ACCEPT'] is equal to "text/html;q=0.9,application/xhtml+xml,application/xml;q=0.8,*/*;q=0.7". This will return: ['application/xhtml+xml', 'text/html', 'application/xml', '*/*'] (not actually, since it returns a generator).
Then you can iterate over the resulting list to select the first content type you know how to respond properly.
Note that this function should work for most cases but do not handle cases such as q=0 which means "Not acceptable".
Sources: HTTP Accept header specification and Quality Values specification
in django 1.10, you can now use, request.content_type, as mentioned here in their doc

Django: creating/modifying the request object

I'm trying to build an URL-alias app which allows the user create aliases for existing url in his website.
I'm trying to do this via middleware, where the request.META['PATH_INFO'] is checked against database records of aliases:
try:
src: request.META['PATH_INFO']
alias = Alias.objects.get(src=src)
view = get_view_for_this_path(request)
return view(request)
except Alias.DoesNotExist:
pass
return None
However, for this to work correctly it is of life-importance that (at least) the PATH_INFO is changed to the destination path.
Now there are some snippets which allow the developer to create testing request objects (http://djangosnippets.org/snippets/963/, http://djangosnippets.org/snippets/2231/), but these state that they are intended for testing purposes.
Of course, it could be that these snippets are fit for usage in a live enviroment, but my knowledge about Django request processing is too undeveloped to assess this.
Instead of the approach you're taking, have you considered the Redirects app?
It won't invisibly alias the path /foo/ to return the view bar(), but it will redirect /foo/ to /bar/
(posted as answer because comments do not seem to support linebreaks or other markup)
Thank for the advice, I have the same feeling regarding modifying request attributes. There must be a reason that the Django manual states that they should be considered read only.
I came up with this middleware:
def process_request(self, request):
try:
obj = A.objects.get(src=request.path_info.rstrip('/')) #The alias record.
view, args, kwargs = resolve_to_func(obj.dst + '/') #Modified http://djangosnippets.org/snippets/2262/
request.path = request.path.replace(request.path_info, obj.dst)
request.path_info = obj.dst
request.META['PATH_INFO'] = obj.dst
request.META['ROUTED_FROM'] = obj.src
request.is_routed = True
return view(request, *args, **kwargs)
except A.DoesNotExist: #No alias for this path
request.is_routed = False
except TypeError: #View does not exist.
pass
return None
But, considering the objections against modifying the requests' attributes, wouldn't it be a better solution to just skip that part, and only add the is_routed and ROUTED_TO (instead of routed from) parts?
Code that relies on the original path could then use that key from META.
Doing this using URLConfs is not possible, because this aliasing is aimed at enabling the end-user to configure his own URLs, with the assumption that the end-user has no access to the codebase or does not know how to write his own URLConf.
Though it would be possible to write a function that converts a user-readable-editable file (XML for example) to valid Django urls, it feels that using database records allows a more dynamic generation of aliases (other objects defining their own aliases).
Sorry to necro-post, but I just found this thread while searching for answers. My solution seems simpler. Maybe a) I'm depending on newer django features or b) I'm missing a pitfall.
I encountered this because there is a bot named "Mediapartners-Google" which is asking for pages with url parameters still encoded as from a naive scrape (or double-encoded depending on how you look at it.) i.e. I have 404s in my log from it that look like:
1.2.3.4 - - [12/Nov/2012:21:23:11 -0800] "GET /article/my-slug-name%3Fpage%3D2 HTTP/1.1" 1209 404 "-" "Mediapartners-Google
Normally I'd just ignore a broken bot, but this one I want to appease because it ought to better target our ads (It's google adsense's bot) resulting in better revenue - if it can see our content. Rumor is it doesn't follow redirects so I wanted to find a solution similar to the original Q. I do not want regular clients accessing pages by these broken urls, so I detect the user-agent. Other applications probably won't do that.
I agree a redirect would normally be the right answer.
My (complete?) solution:
from django.http import QueryDict
from django.core.urlresolvers import NoReverseMatch, resolve
class MediapartnersPatch(object):
def process_request(self, request):
# short-circuit asap
if request.META['HTTP_USER_AGENT'] != 'Mediapartners-Google':
return None
idx = request.path.find('?')
if idx == -1:
return None
oldpath = request.path
newpath = oldpath[0:idx]
try:
url = resolve(newpath)
except NoReverseMatch:
return None
request.path = newpath
request.GET = QueryDict(oldpath[idx+1:])
response = url.func(request, *url.args, **url.kwargs)
response['Link'] = '<%s>; rel="canonical"' % (oldpath,)
return response