i'm new to django and i'd like to know how the url maps work in detail.
from django.conf.urls import url
from polls import views
urlpatterns =[
url(r'^$',views.index,name='index')
]
the url function takes 3 parameters, could you explain how they work and what functionalies they have.
I've searched for this, but no detailed information are available for an absolute beginner
The Django URL dispatcher contains urlpatterns which is a Python list of url() instances.
The url(regex, view, kwargs=None, name=None) function can take 4 arguments:
regex: Regular expression, pattern matching the url.
view: View name, path, function or the result of as_view() for class-based views. It can also be an include().
kwargs: Allows you to pass additional arguments to the view function or method.
name: Naming URL patterns.
Related
I am doing a django project, and is very confused about reverse, reverse_lazy and redirect.
Can redirect function redirect with parameters? Or should I change method to reverse whenever I want to post parameters?
Can redirect function redirect with parameters?
Yes. Imagine that you have a url pattern with:
path('foo/<str:bar>/<id:pk>/', name='some_path')
you can redirect to that path with:
return redirect('some_path', bar='value-for-bar', pk=1425)
is very confused about reverse, reverse_lazy and redirect.
reverse and reverse_lazy determine the path for a given view name. That path is a string, not a HTTP response, you can not return such string as a result for a view.
The redirect(…) function [Django-doc] will call reverse(…) function [Django-doc] internally and wrap the result in a HttpResponseRedirect [Django-doc] or HttpResponsePermanentRedirect [Django-doc].
It thus combines two layers with each other: the urls layer to calculate the path, and the view layer to construct a HTTP response, that is why it is defined in the django.shortcuts module [Django-doc].
the redirect url is
"liveinterviewList/2"
and, ofcourse, I declare that url in url.py
more over, when I type that url in browser manualy, it works well.
what's the matter?
more question.
at this case, I write the user_id on the url.
I think, it is not good way to make url pattern.
but I don't know how I deliver the user_id variable without url pattern.
please give me a hint.
What HariHaraSudhan left out was how to use parameters. For your case, you would want something like:
path(r'liveinterviewList/<int:userId>', ..., name='live-interview'),
And then when you are ready to reverse, use this:
reverse('app:live-interview', kwargs={ 'userId': userId })
where app is the name of the app in which your view lives. If your url lives in the main urls file , you don't need the app: prefix.
Django reverse function accepts the name of the path not the URL.
lets say i have url patterns like this
urlpatterns = [
path('/users/list', name="users-list")
]
In my view i can use like this
def my_view(request):
return redirect(reverse("users-list"));
You should add a name to your path url and use it to redirect.
As the django doc says :
urls :
urlpatterns = [
path('/name', name="some-view-name")
]
def my_view(request):
...
return redirect('some-view-name')
I have experienced using reverse within get_absolute_url method in the model, but I wish I have an idea about the difference between reverse and redirect, I have tried to search on google about it but there is almost nothing
I don't know what should I write also to convince stack overflow that I don't have any other description
Reverse and redirect have a different meaning. Here is a simple explanation:
reverse in Django is used to find the URL of a given resource. Let's say that you have a blog website and from the main page, you want to provide links to your blog posts. You can of course just hard-code /posts/123/ and just change the ID of your blog post in URL, but that makes it hard to change your URL for the post in the future. That's why Django comes with reverse function. All you need to do is to pass the name of your URL path (defined in your urlpatterns) and Django will find for you the correct URL. It is called reverse because it is a reverse process of determining which view should be called for a given URL (which process is called resolving).
Redirects are not specific to Django or any other web frameworks. Redirect means that for a given URL (or action), the user should be instructed to visit a specific URL. This can be done by sending a special redirect request and from there the browser will handle it for the user, so no user action is required in that process. You can use reverse in redirect process to determine the URL that the user should be redirected to.
GwynBleidD has given you the answer, but there is a reason why you might be getting confused. The Django redirect shortcut accepts arguments in several different forms. One of them is a URLpattern mane, with arguments, that is then passed to reverse to generate the actual URL to redirect to. But that's just a shortcut, to enable a common pattern.
here's an example
app/views
#imports
def indexView(request):
....
return render(request, 'index.html', context)
def loginView(request):
....
return redirect('index')
def articleDetailView(request, id):
....
return redirect(reverse('article-comments', kwargs={'id':id})
def articleCommentsView(request, id):
....
return render(request, 'comment_list.html', context)
proj/urls
#imports
urlpatterns = [
....,
path('', include(app.urls))
]
app/urls
#imports
urlpatterns = [
....,
path('index/', index, name='index'),
path('login/', loginView, name='login'),
path('article/<int:id>/detail', articleDetailView, name='article-detail'),
path('article/<int:id>/comments/',articleCommentsView, name='article-comments')
....,
]
For loginView redirect will return url as-is i.e. 'index' which will be appended to base(project) urlpatterns. Here redirect(reverse('index')) will also work since kwargs is None by default for reverse function and 'index' view doesn't require any kwarg. It returns '/index/' which is passed to redirect(which again will be appended to base urls).
One thing to note is that reverse is used to make complete url - needed for redirect - that is shown in 'articleDetailview'.
The most basic difference between the two is :
Redirect Method will redirect you to a specific route in General.
Reverse Method will return the complete URL to that route as a String.
In urls.py I want to map a specific legacy URL to a specific dynamic resource:
urlpatterns += patterns('example.example',
url(r'^example/example.html$', views.myview(request,url_slug='example-slug')),
)
With the view looking like this:
def myview(request, slug):
a = get_object_or_404(MyObject, url_slug=slug)
How can I get the request parameter, or do this more cleanly?
You're making this too complicated. Django's URLs already pass the request, and you can specify any additional parameters in the third argument of the url entry:
url(r'^example/example.html$', views.myview, {'url_slug': 'example-slug'})
in my urls.py I need to invoke a generic CreateView that requires a success_url parameter. The "success" URL contains an identifier that I need to pass to the reverse() URL search function. I get this parameter from the URL of the CreateView. please see the code below. I need to grab the value of the <pk> parameter in the "create" url, and pass it on to the "success" url. how is this done?
thanks
konstantin
PS: using django trunk
...
url(r'^path/(?P<pk>\d+)/apply/$',
generic.CreateView.as_view(form_class=MyForm,
success_url=reverse_lazy('success', args=[???<pk>???]),
template_name='create.html'), name='create'),
url(r'path/(?P<pk>\d+)/apply/success/$',
generic.TemplateView.as_view(template_name='success.html'), name='success'),
...
This is explained in the documentation:
success_url may contain dictionary string formatting, which will be interpolated against the object's field attributes. For example, you could usesuccess_url="/polls/%(slug)s/" to redirect to a URL composed out of the slug field on a model.