I am currently completing the final capstone project for Django on Codecademy, and I've come across a comprehension issue.
On Codecademy, they state that it's used to redirect to the homepage when a user submits data, while the Django documentation for get_absolute_url seems to make no reference to redirects.
I currently have no absolute urls defined for any of my models, and these are my url patterns and views.
At this stage, I'm just trying to understand the purpose of defining an absolute URL in a model, and where the appropriate places to utilize it are. I'm very confused about it's function currently, and would appreciate a simplified explanation with examples.
Related
I have started learning DRF just a while ago and had a little question -
how can I code one API that will return HTML for the site that I am currently working on and return JSON format for other "clients"(e.g. mobile apps, desktop, etc)?
I have tried to search for this information, but didn't found any answering content.
The only way I see is to create default Django views for the site and create separated API's for other requests. Can anybody tell me if I am right and need to do so, or there is some code that is solving my problem?
Ultimately, you can think of it as a whole separate set of views, urls and instead of models you have a serializer. Within you're app you can create an API folder. Within that directory you will need to have an '_ _ init _ _.py', 'urls.py', 'views.py' and a 'serializers.py'. Its analogous to creating a standard url, view, model structure to display an HTML page, but without the HTML template. Make distinct urls for the serializers too. For example for login do something like this:
path('my_app_api/login', serializer_view)
Youtube has tons of videos if you search django rest framework
I would like to know how Django is resolving request urls urlpatterns in general.
My theory:
Django at some point turns all its urlpatterns into list of regexes, and then tries to match them against incoming Request's url.
Question:
Am I correct? If yes, can somebody point me out where in source code is this happening?
Looks like there is nothing about this mentioned in django docs, and I feel like I am doing a blind search in source code. Any insights appreciated.
The process is described here. In short:
Django determines the root URLconf module to use....
Django loads that Python module and looks for the variable urlpatterns. This should be a Python list of django.urls.path() and/or django.urls.re_path() instances.
Django runs through each URL pattern, in order, and stops at the first one that matches the requested URL.
Once one of the URL patterns matches, Django imports and calls the given view, which is a simple Python function (or a class-based view)....
If no URL pattern matches, or if an exception is raised during any point in this process, Django invokes an appropriate error-handling view....
I'm trying to add new url patterns to the projects urls.py(not an apps urls) on the fly. I couldn't find anything about this on stackoverflow!
Edit:
I'm writing a simple scaffolding app. For a given model, I create forms, views, templates, and urls.py for an app on the fly. The last thing is to add(attach) urls.py of the app to the urls.py of the project automatically.
Django routing does not allow such dynamics, as the routing table is built once in the application startup and never refreshed. Even if it where refreshable then you should communicate the routing table changes across different server processes using database, sockets, Redis pubsub or such mechanism and you would be bending Django framework for something it was not designed to do.
Instead, as the suggestion is, you need one generic regex hook to match the all URLs you want to be "dynamic". Then, inside the view code of this generic URL you can do your own routing based on the full input URL and the available data (E.g. from database). You can even build your own Django URL resolver inside the view if you wish to do so, though this might not be a problem-free approach.
Generally, the better approach to solve the situation like this is called traversal. Django does not natively support traversal, but other Python web frameworks like Pyramid support traversal.
I couldn't find this info in the Django docs, but I'm sure it is there, I'm just very new and don't know what terms/etc to search on.
How are Django page templates assigned to each page?
I have a login to a Django site, and also SFTP access to the site. I don't think my Django login is a superuser/full-admin though because the interface seems pretty limited compared to other CMS systems. I can edit pages, posts and the media library, but I don't see anything that says how each page is assigned a template.
For example, I have this file /mysite/templates/pages/index.html
I know that template is being used for the home page because it has all of the content that is specific to the home page on it, and changes I make show up on the home page.
I tried copying that file to test.html, but when I browse to test.html in my browser, I get a 404 error (I also get that error if I go to index.html). So there must be something else that maps a template to a page, but I'll be dambed if I can find it. Will I need more access to the admin area, or can I do something with SFTP? I also have SSH access but wasn't able to follow any of the steps online to create a new superuser account for me, for Django.
Edit: Thanks for both answers, after I work through this I'll accept whichever helped the most. I do not have a views.py file, but I think it might be using an extra module for this routing, I have this in my urls.py file:
urlpatterns = patterns("",
("^admin/", include(admin.site.urls)),
url("^$", "mezzanine.pages.views.page", {"slug": "/"}, name="home"),
("^", include("mezzanine.urls")),
)
Is this "mezzanine" something different which changes the answer (location of views.py or list of views)?
url.py is the file that maps the urls to methods that return rendered templates. In essence you define the url and a method and when someone goes to that url, that method gets called which returns a HTTP response with the rendered template. This map is called urlpatterns. In the following example when someone goes to yourwebsite/blog then in the blog apps, view.py, page method is called, which will use a template and render that with specific information.
urlpatterns = patterns('',
url(r'^blog/$', 'blog.views.page'),
url(r'^blog/page(?P<num>\d+)/$', 'blog.views.page'),
)
Have a look at this link.
https://docs.djangoproject.com/en/dev/topics/http/urls/
Django uses urls.py files to map paths to views. This match is resolved using regular expressions. When a match is found, Django executes the associated view (usually inside views.py). The view is in charge to render the template required for the path (by finding it on the server's hard disk and loading it).
All aforementioned means that there's no direct association between a url path (i.e www.example.com/path/to/page) and a file on the server's hard disk (i.e /server/path/to/page). It's all performed dynamically by Django's engine when a request comes in.
If you want to know which view is gonna be generated for a specific path, follow the regexs at urls.py until you find the path you're looking for. Then open the view for that url and see inside which template it is rendering.
Reading doc's URL Dispatcher is a good point to start learning about this.
Hope this helps!
I'm in a process of migrating Rails project into Django. Rails project was built using restful routes and it never touches the database. Instead, it simply redirects to different methods which all call an external service with the specified action method. Now, I have found a number of frameworks for django that provide restful capability plus a bunch of bells and whistles, but it's an overkill for my current case.
As an alternative, I can ignore action method in urls.py by simply providing a regex to validate urls and then parse the request method in views.py, redirecting to the appropriate method. Is this a way to go or are there any other approaches that I can look at?
Class based views look like the idiomatic way to organize restful view functions by request method.
Django snippets has several simple example implementations.