Calling a function from HTML to Python file

Question

I have a index.html page with a list of "cards", where each card have a "Click to Select" link.

When user click in this link i'd like to call a function in python to select this item, see:

def selectItem(request, item):
    #so something with this item

so, in my html pagE:

<div class="card-action">
                            <a href="{{ selectItem(myitem) }}">Selecionar</a>
                        </div>

This don't work. What is the right way to do it ?

You need to pass an URL to the view, so {% url 'view_name' item_id=myitem.id %} given that is a view, and you do the proper handling of the URL. Furthermore you can not just pass the object, since that object can not be "shipped". You can for example use the id, and the do the proper processing in the view (to turn the id back into an object). — willeM_ Van Onsem
– willeM_ Van Onsem, Commented Sep 9, 2018 at 13:54

willeM_ Van Onsem · Accepted Answer · 2018-09-09 14:04:20Z

3

You can not call a function like that. A browser requests data with an HTTP request, and the server answers with an (HTTP) response. Such requests have a URL, and Django can route the request - with the URL - to the right view that will calculate a response.

We thus need to construct a view that can then be called. Your call is already quite close:

# app/views.py

from django.http import HttpResponse

def select_item(request, item_id):
    # so something with this item_id
    # ...
    return HttpResponse()

Since most objects are not serializable (and usually you do not want that anyway, since it would expose a lot of (potentially sensitive) data to the user, we thus need to work with an id (an identifier that is for example stored in the database that corresponds to an object).

The response contains the data in the response. Frequently that is HTML code that is then rendered by the browser.

Now in urls.py, we can specify how the url looks like, for example:

# app/urls.py

from django.urls import path
from app.views import select_item

urlpatterns = [
    path('select_item/<int:item_id>/', select_item, name='select_item_view'),
    # ...
]

The urlpatterns need to be included in the root urlpatterns (in the project root).

Now in the HTML template, we can generate the URL that matches with this view, something similar to:

<div class="card-action">
  <a href="{% url 'select_item_view' item_id=myitem.id %}">Selecionar</a>
</div>

Django will then make sure that the href points to an URL that refers to the select_item view with the correct parameter.

answered Sep 9, 2018 at 14:04

willeM_ Van Onsem

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3 Comments

Ronaldo Lanhellas Over a year ago

Very useful answer, thanks. If you can help I have another doubt. Should I create a view_select.py or put all in same view.py file ? I think that view.py very verbose

willeM_ Van Onsem Over a year ago

Usually all views are put in views.py, but you can indeed write different files. Wrtiting every view in a separate file would however be more the "Java-ish" approach.

Ronaldo Lanhellas Over a year ago

Thanks again Willem

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