I'm getting ready to move an old Classic ASP site to a new Django system. As part of the move we have to setup some of the old URLs to point to the new ones.
For example,
http://www.domainname.com/category.asp?categoryid=105 should 301 to http://www.domainname.com/some-category/
Perhaps I'm regex stupid or something, but for this example, I've included in my URLconf this:
(r'^asp/category\.asp\?categoryid=105$', redirect_to, {'url': '/some-category/'}),
My thinking is that I have to escape the . and the ? but for some reason when I go to test this, it does not redirect to /some-category/, it just 404s the URL as entered.
Am I doing it wrong? Is there a better way?
To elaborate on Daniel Roseman's answer, the query string is not part of the URL, so you'll probably want to write a view function that will grab the category from the query string and redirect appropriately. You can have a URL like:
(r'^category\.asp', category_redirect),
And a view function like:
def category_redirect(request):
if 'categoryid' not in request.GET:
raise Http404
cat_id = request.GET['category']
try:
cat = Category.objects.get(old_id=cat_id)
except Category.DoesNotExist:
raise Http404
else:
return HttpResponsePermanentRedirect('/%s/' % cat.slug)
(Altered to your own tastes and needs, of course.)
Everything after the ? is not part of the URL. It's part of the GET parameters.
Related
This question might reveal a gaping hole in my knowledge of json queries, but I'm trying to get json data to display on a view with the following URL.
http://localhost:8000/structures/hydrants/json?id=%3D2/
Here's my URL regex:
url(r'^hydrants/json\\?id=(?P<hydrant_id>\d+)/$', views.hydrant_json, name='hydrant_json'),
and the view:
def hydrant_json(request, hydrant_id):
hydrant = get_object_or_404(Hydrant, pk=hydrant_id)
data = [hydrant.json()]
return HttpResponse(json.dumps(data), content_type='application/json')
Obviously, the question mark is throwing it off, because if I make the regex
url(r'^hydrants/json/id=(?P<hydrant_id>\d+)/$', views.hydrant_json, name='hydrant_json'),
then the following URL will work:
http://localhost:8000/structures/hydrants/json/id%3D2/
Thanks in advance!
If you want to send the data as GET parameters, you can simply do:
url(r'^hydrants/json/$', views.hydrant_json, name='hydrant_json'),
url(r'^hydrants/json/(?P<hydrant_id>\d+)/$', views.hydrant_json, name='hydrant_json_with_key'),
and views:
def hydrant_json(request, hydrant_id=None):
if not hydrant_id:
hydrant_id = request.GET.get('id')
if not hydrant_id: #if hydrant_id is not received for some reason, throw 404.
raise Http404
hydrant = get_object_or_404(Hydrant, pk=hydrant_id)
data = [hydrant.json()]
return HttpResponse(json.dumps(data), content_type='application/json')
Here, you are defining flexible ways of sending hydrant_id into the view.
By default, for a GET request, request.GET would have all the get parameters - example: ?id=123
Also, if you want to send hydrant_id as a part of the URL, You can just do
http://localhost:8000/structures/hydrants/json/302/
Please note, 3D2 would never get matched as a URL in the regex because your URL is looking for \d+ which is digits only.
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
If I put this in my view:
if slug == 'old-path':
return HttpResponsePermanentRedirect('new-path')
it skips my slugbased view and returns 404.
How do I easily return 301 and "reprocess" my view so I don't get a 404?
EDIT
#Pydev UAs comment was the correct answer in this case, but I appreciated the detailed answer by John Debs, which gave me the hint to look into named urls, which I didn't know about. Thanks all.
Add from django.core.urlresolvers import reverse to your list of imports and then try this bit of code:
if slug == 'old-path':
return HttpResponsePermanentRedirect(reverse('new-path'))
The problem you had was that HttpResponsePermanentRedirect() needs a path but you were providing it with a slug.
reverse() will search through your named URLs for the string you provide and return a path, which can then be redirected to properly.
N.B This question has been significantly edited before the first answer was given.
Hi,
I'm fairly new to django, so apologies if I'm missing something obvious.
I've got a urls.py file that looks like this:
urlpatterns = patterns(
'',
(r'^$', 'faros.lantern.views.home_page'),
(r'^login/$', 'django.contrib.auth.views.login'),
(r'^logout/$', 'django.contrib.auth.views.logout'),
(r'^about/$', 'faros.lantern.views.about_page_index', {}, 'about_page_index'),
(r'^about/(?P<page_id>([a-z0-9]+/)?)$', 'faros.lantern.views.about_page', {}, 'about_page'),
)
Views that looks like this:
def about_page_index(request):
try:
return render_to_response('lantern/about/index.html', context_instance=RequestContext(request))
except TemplateDoesNotExist:
raise Http404
def about_page(request, page_id):
page_id = page_id.strip('/ ')
try:
return render_to_response('lantern/about/' + page_id + '.html', context_instance=RequestContext(request))
except TemplateDoesNotExist:
raise Http404
And a template that includes this:
Contact
Contact
I'm getting this error message:
Caught an exception while rendering: Reverse for '<function about_page at 0x015EE730>' with arguments '()' and keyword arguments '{'page_id': u'contact'}' not found. The first reverse works fine (about_page_index), generating the correct URL without error messages.
I think this is because the request argument to the about_page view (request) is used, so I need to pass it in when I generate the URL in my template. Problem is, I don't know how to get to it, and searching around isn't getting me anywhere. Any ideas?
Thanks,
Dom
p.s. As an aside, does that method of handling static "about" type pages in an app look horrific or reasonable? I'm essentially taking URLs and assuming the path to the template is whatever comes after the about/ bit. This means I can make the static pages look like part of the app, so the user can jump into the about section and then right back to where they came from. Comments/Feedback on whether this is djangoic or stupid appreciated!
If I guess correctly from the signature of your view function (def about_page(request, page_id = None):), you likely have another URL configuration that points to the same view but that does not take a page_id parameter. If so, the django reverse function will see only one of these, and it's probably seeing the one without the named page_id regex pattern. This is a pretty common gotcha with reverse! :-)
To get around this, assign a name to each of the url patterns (see Syntax of the urlpatterns variable). In the case of your example, you'd do:
(r'^about/(?P<page_id>([a-z]+/)?)$', 'faros.lantern.views.about_page',
{}, 'about_with_page_id')
and then in the template:
Contact
Edit
Thanks for posting the updated urls.py. In the url template tag, using the unqualified pattern name should do the trick (note that I'm deleting the lantern.views part:
Contact
Contact
Edit2
I'm sorry I didn't twig to this earlier. Your pattern is expressed in a way that django can't reverse, and this is what causes the mismatch. Instead of:
r'^about/(?P<page_id>([a-z]+/)?)$'
use:
r'^about/(?P<page_id>[a-z0-9]+)/$'
I created a dummy project on my system that matched yours, reproduced the error, and inserted this correction to success. If this doesn't solve your problem, I'm going to eat my hat! :-)
I am currently defining regular expressions in order to capture parameters in a URL, as described in the tutorial. How do I access parameters from the URL as part the HttpRequest object?
My HttpRequest.GET currently returns an empty QueryDict object.
I'd like to learn how to do this without a library, so I can get to know Django better.
When a URL is like domain/search/?q=haha, you would use request.GET.get('q', '').
q is the parameter you want, and '' is the default value if q isn't found.
However, if you are instead just configuring your URLconf**, then your captures from the regex are passed to the function as arguments (or named arguments).
Such as:
(r'^user/(?P<username>\w{0,50})/$', views.profile_page,),
Then in your views.py you would have
def profile_page(request, username):
# Rest of the method
To clarify camflan's explanation, let's suppose you have
the rule url(regex=r'^user/(?P<username>\w{1,50})/$', view='views.profile_page')
an incoming request for http://domain/user/thaiyoshi/?message=Hi
The URL dispatcher rule will catch parts of the URL path (here "user/thaiyoshi/") and pass them to the view function along with the request object.
The query string (here message=Hi) is parsed and parameters are stored as a QueryDict in request.GET. No further matching or processing for HTTP GET parameters is done.
This view function would use both parts extracted from the URL path and a query parameter:
def profile_page(request, username=None):
user = User.objects.get(username=username)
message = request.GET.get('message')
As a side note, you'll find the request method (in this case "GET", and for submitted forms usually "POST") in request.method. In some cases, it's useful to check that it matches what you're expecting.
Update: When deciding whether to use the URL path or the query parameters for passing information, the following may help:
use the URL path for uniquely identifying resources, e.g. /blog/post/15/ (not /blog/posts/?id=15)
use query parameters for changing the way the resource is displayed, e.g. /blog/post/15/?show_comments=1 or /blog/posts/2008/?sort_by=date&direction=desc
to make human-friendly URLs, avoid using ID numbers and use e.g. dates, categories, and/or slugs: /blog/post/2008/09/30/django-urls/
Using GET
request.GET["id"]
Using POST
request.POST["id"]
Someone would wonder how to set path in file urls.py, such as
domain/search/?q=CA
so that we could invoke query.
The fact is that it is not necessary to set such a route in file urls.py. You need to set just the route in urls.py:
urlpatterns = [
path('domain/search/', views.CityListView.as_view()),
]
And when you input http://servername:port/domain/search/?q=CA. The query part '?q=CA' will be automatically reserved in the hash table which you can reference though
request.GET.get('q', None).
Here is an example (file views.py)
class CityListView(generics.ListAPIView):
serializer_class = CityNameSerializer
def get_queryset(self):
if self.request.method == 'GET':
queryset = City.objects.all()
state_name = self.request.GET.get('q', None)
if state_name is not None:
queryset = queryset.filter(state__name=state_name)
return queryset
In addition, when you write query string in the URL:
http://servername:port/domain/search/?q=CA
Do not wrap query string in quotes. For example,
http://servername:port/domain/search/?q="CA"
def some_view(request, *args, **kwargs):
if kwargs.get('q', None):
# Do something here ..
For situations where you only have the request object you can use request.parser_context['kwargs']['your_param']
You have two common ways to do that in case your URL looks like that:
https://domain/method/?a=x&b=y
Version 1:
If a specific key is mandatory you can use:
key_a = request.GET['a']
This will return a value of a if the key exists and an exception if not.
Version 2:
If your keys are optional:
request.GET.get('a')
You can try that without any argument and this will not crash.
So you can wrap it with try: except: and return HttpResponseBadRequest() in example.
This is a simple way to make your code less complex, without using special exceptions handling.
I would like to share a tip that may save you some time.
If you plan to use something like this in your urls.py file:
url(r'^(?P<username>\w+)/$', views.profile_page,),
Which basically means www.example.com/<username>. Be sure to place it at the end of your URL entries, because otherwise, it is prone to cause conflicts with the URL entries that follow below, i.e. accessing one of them will give you the nice error: User matching query does not exist.
I've just experienced it myself; hope it helps!
These queries are currently done in two ways. If you want to access the query parameters (GET) you can query the following:
http://myserver:port/resource/?status=1
request.query_params.get('status', None) => 1
If you want to access the parameters passed by POST, you need to access this way:
request.data.get('role', None)
Accessing the dictionary (QueryDict) with 'get()', you can set a default value. In the cases above, if 'status' or 'role' are not informed, the values are None.
If you don't know the name of params and want to work with them all, you can use request.GET.keys() or dict(request.GET) functions
This is not exactly what you asked for, but this snippet is helpful for managing query_strings in templates.
If you only have access to the view object, then you can get the parameters defined in the URL path this way:
view.kwargs.get('url_param')
If you only have access to the request object, use the following:
request.resolver_match.kwargs.get('url_param')
Tested on Django 3.
views.py
from rest_framework.response import Response
def update_product(request, pk):
return Response({"pk":pk})
pk means primary_key.
urls.py
from products.views import update_product
from django.urls import path
urlpatterns = [
...,
path('update/products/<int:pk>', update_product)
]
You might as well check request.META dictionary to access many useful things like
PATH_INFO, QUERY_STRING
# for example
request.META['QUERY_STRING']
# or to avoid any exceptions provide a fallback
request.META.get('QUERY_STRING', False)
you said that it returns empty query dict
I think you need to tune your url to accept required or optional args or kwargs
Django got you all the power you need with regrex like:
url(r'^project_config/(?P<product>\w+)/$', views.foo),
more about this at django-optional-url-parameters
This is another alternate solution that can be implemented:
In the URL configuration:
urlpatterns = [path('runreport/<str:queryparams>', views.get)]
In the views:
list2 = queryparams.split("&")
url parameters may be captured by request.query_params
It seems more recommended to use request.query_params. For example,
When a URL is like domain/search/?q=haha, you would use request.query_params.get('q', None)
https://www.django-rest-framework.org/api-guide/requests/
"request.query_params is a more correctly named synonym for request.GET.
For clarity inside your code, we recommend using request.query_params instead of the Django's standard request.GET. Doing so will help keep your codebase more correct and obvious - any HTTP method type may include query parameters, not just GET requests."