CODEWITHSUNDEEP
django
Aleksei Khatkevich
Aleksei Khatkevich

Reputation: 2197

Django| generate random url based on URl or PATH from urlconfig

I have a question regarding generating example urls according the Django url and path.

For example if I have 2 urls like:

 path('example/<int:example_id>/', views.some_view, name='example')

 url(r'^example/(?P<example_id>[0-9]+)/$', views.some_view, name='example')

Is it possible to generate somehow by Django built-in means example full-urls for tests like:

example/234/
example/93/
example/228/
etc…

randomly.

For different urls based on concrete name + regex or converter parameters?

In other words where in source code Django understands that <int:example_id> is an integer and so on. If I have something like : 1) I expect example/ 2) I expect int - I would be able to use it to generate random example url.

Hopefully this is clear...

These urls are just an example. Real urls will differ.

Thank you.

Upvotes: 1

Views: 691

Answers (1)

willeM_ Van Onsem
willeM_ Van Onsem

Reputation: 476719

In other words where in source code Django understands that <int:example_id> is an integer and so on.

This is in essence looking for <…:…> patterns in the path. Django has furthermore a set of path converters. The standard ones are int, str, slug, uuid, path, but you can define your own path converters. Indeed, the Django documentation has a section registering custom path converters that explains how you can design your own path converters.

What a path basically does is constructing a regex. It thus searches for patterns like <int:example_id>. Since you here used int, the IntConverter [GitHUb] is used:

class IntConverter:
    regex = '[0-9]+'

    def to_python(self, value):
        return int(value)

    def to_url(self, value):
        return str(value)

Here it will thus replace the <int:example_id> by (?<example_id>[0-9]+), where the regex part thus will be used.

A path(…) does not only constructs a regex. It also automatically maps the captured items to a Python object by calling .to_python(…). This thus means that if you work with re_path(r'^example/(?P<example_id>[0-9]+)/$', …), then example_id will be a string, but for path('example/<int:example_id>/', …), it will automatically call int(…) on the captured string, and thus pass an int object. Often that does not make much difference.

This also holds when you serialize an object: you can pass a value, and it will call .to_url(…) on the object to convert it to a string representation for the generated URL. This thus means that you can write custom path converters that thus perform more sophisticated conversions.

I expect example/ 2) I expect int - I would be able to use it to generate random example url.

Well eventually it boils down to a regular expression. A regular expression can be converted into a finite state machine, so we can generate random valid strings. For example exrex [GitHub] is capable to generate all valid strings (this is often an generator that will keep proposing new strings), or random strings that match the regular expression. It is however not said that because it matches the path(…), that it will be sensical for the view. If you for example use this int as the primary key of a Post object it is fetching, then for random URLs, it is likely that you will generate URLs for non-existing Posts.

Upvotes: 1

Related Questions