[Django] #32343: Chained autocomplete_fields in contrib.admin

[Django]

#32343: Chained autocomplete_fields in contrib.admin
-----------------------------------------+------------------------
Reporter: adontz | Owner: nobody
Type: New feature | Status: new
Component: contrib.admin | Version: 3.1
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
-----------------------------------------+------------------------
Sometimes querysets for autocomplete_fields should be dependent and
selection should be chained.

Imagine there is a model Address with references to Country and City
models
{{{
class Country(models.Model):
id = models.AutoField(primary_key=True)
name = models.CharField(max_length=100)

class City(models.Model):
id = models.AutoField(primary_key=True)
country = models.ForeignKey(Country, on_delete=models.CASCADE)
name = models.CharField(max_length=100)

class Address(models.Model):
id = models.AutoField(primary_key=True)
country = models.ForeignKey(Country, on_delete=models.CASCADE)
city = models.ForeignKey(City, on_delete=models.CASCADE, null=True,
blank=True)
}}}
Also imagine admin form displays a Country drop-down with the list of all
countries and a City drop-downwith. A user reasonably expects City drop-
down to contain the list of all cities within previously selected country,
but not all cities in the entire world.

Unfortunately, when current version of Django calls
/admin/app/model/autocomplete no information about current selection in
other drop-downs is sent, so there is no way to select cities of a
specific country for a new unsaved model. So overriding "def
get_search_results(self, request, queryset, search_term)" gives nothing,
as required information is not available.

However, a small change to autocomplete.js allowed me to easily implement
what I need.
{{{
'use strict';
{
const $ = django.jQuery;
const init = function($element, options) {
const settings = $.extend({
ajax: {
data: function(params) {
var result = {
'term': params.term,
'page': params.page
};

$('.admin-autocomplete').each(function(index) {
result['selected_' + $(this).attr('name')] =
$(this).val(); // Pass selections of all other select2 with request.
});

return result;
}
}
}, options);
$element.select2(settings);
};
...
// the rest is not changed
}}}
Now, in "def get_search_results(self, request, queryset, search_term)" I
can extract all required information from "request.GET"

I am no sure neither about if all autocomplete selects should be included,
if all selects should be included. Probably it would be better to
introduce some kind of opt-in configuration. Also, I am not sure about
"selected_" prefix. I understand that this is not a generic code which
should be included in the next version of Django. However, this small
change works pretty fine for me, allowing to build much more friendly
admin forms. I am ready to present pull request, if maintainers will be so
kind to comment on idea in general and point at issues I have missed.

--
Ticket URL: <https://code.djangoproject.com/ticket/32343>
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[Django]

#32343: Chained autocomplete_fields in contrib.admin

-------------------------------+--------------------------------------

Reporter: adontz | Owner: nobody
Type: New feature | Status: new
Component: contrib.admin | Version: 3.1

Severity: Normal | Resolution:

Keywords: | Triage Stage: Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0

-------------------------------+--------------------------------------
Description changed by adontz:

Old description:

New description:

I am not sure neither about if all autocomplete selects should be
included, nor if all selects should be included. Probably it would be

better to introduce some kind of opt-in configuration. Also, I am not sure
about "selected_" prefix. I understand that this is not a generic code
which should be included in the next version of Django. However, this
small change works pretty fine for me, allowing to build much more
friendly admin forms. I am ready to present pull request, if maintainers
will be so kind to comment on idea in general and point at issues I have
missed.

--

--
Ticket URL: <https://code.djangoproject.com/ticket/32343#comment:1>

[Django]

#32343: Chained autocomplete_fields in contrib.admin

-------------------------------+--------------------------------------
Reporter: Roman | Owner: nobody
Type: New feature | Status: closed
Component: contrib.admin | Version: 3.1
Severity: Normal | Resolution: wontfix

Keywords: | Triage Stage: Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0

-------------------------------+--------------------------------------
Changes (by Carlton Gibson):

* status: new => closed
* resolution: => wontfix

Comment:

Hi Roman. Thanks for the report.

I think this is out-of-scope for us at the moment. It's the sort of thing
I've done as a custom widget in the admin (a bit of JS and an JSON
endpoint behind it) but I suspect if would involve quite a lot of extra
complexity.

**If you really want it** a proof-of-concept showing the changes involved
would help asses the feasibility.

--
Ticket URL: <https://code.djangoproject.com/ticket/32343#comment:2>