SearchFilter gives error in Full-text search using ('@') even when using Django and PostgreSQL

[kushshiv]

Issue :

SearchFilter gives error in Full-text search using ('@').

Documentation :

Documentation link

The search behavior may be restricted by prepending various characters to the search_fields.

'^' Starts-with search.
'=' Exact matches.
'@' Full-text search. (Currently only supported Django's PostgreSQL backend.)
'$' Regex search.

Error:

FieldError("Unsupported lookup 'search' for CharField or join on the field not permitted.")

Using (Django 3.2.4) and (PostgreSQL - 13.1)

[tomchristie]

There's not enough information here for anyone to be able to help you.

[kushshiv]

That will be for the filtering part... According to documentation here for SearchFilter, I can do search the on the fields specified in the search_fields. Please correct if I am doing something wrong.
Search Filter Document
As per document :

This will allow the client to filter the items in the list by making queries such as:

http://example.com/api/users?search=russell

[tomchristie]

Oh yes. Perhaps the two different filters you're using here are conflicting? I can't understand the intent behind having both DjangoFilterBackend and SearchFilter here.

Might be you'd want to swap the ordering of them around...

filter_backends = [SearchFilter, DjangoFilterBackend, OrderingFilter]

[kushshiv]

Ok. This time I tried with only SearchFilter, and search_fields... Still the same issue...

queryset = Moment.objects.all()
serializer_class = MomentSerializer
filter_backends = [SearchFilter]
search_fields = ['@name']

[tomchristie]

Still the same issue...

I'd double check that - the "Unsupported lookup" error is from django-filter...

https://github.com/carltongibson/django-filter/blob/fe90e3a5fdeaff0983d1325a3e9dcf3458ef078f/django_filters/exceptions.py

[kushshiv]

Finally got it. It will only work if django.contrib.postgres is added in the INSTALLED_APPS.

https://docs.djangoproject.com/en/3.2/ref/contrib/postgres/search/#the-search-lookup

To use the search lookup, 'django.contrib.postgres' must be in your INSTALLED_APPS.

It would be highly appreciated if mention in the same document as well.
PS : There was one more issue raised for the same. #5795

[kushshiv]

It will only work if django.contrib.postgres is added in the INSTALLED_APPS.

https://docs.djangoproject.com/en/3.2/ref/contrib/postgres/search/#the-search-lookup

To use the search lookup, 'django.contrib.postgres' must be in your INSTALLED_APPS.

[sevdog]

On django admin site is it possible to use a SearchVectorField for searches by putting field__exact in search_fields, from django docs:

If you don’t want to use icontains as the lookup, you can use any lookup by appending it the field. For example, you could use exact by setting search_fields to ['first_name__exact'].

I expected the SearchFilter to behave like that, but as of now is not. If you try to use any lookup it does not work at all.

It would be a good thing if SearchFilter.construct_search was inspired by the admin method:

https://github.com/django/django/blob/107865780aa44914e21d27fdf4ca269bc61c7f01/django/contrib/admin/options.py#L1132-L1159

[auvipy]

drf is mainly based on django ORM. and contrib apps, but I don't think it follow much of django Admin patterns. I could be wrong though

[sevdog]

If you inspect the sources both of SearchFilter and django.contrib.admin search implementation they are too much lookalike to assert that SearchFilter is not "derived" from it (apart that in django.contrib some undocumented methods like models.Q.create).
Also looking at SearchFilter docs it exposes quite the same programming API of ModelAdmin.search_fields (especially the prefix-lookup mechanism, ie: ^field which means field__istartswith in both).

Last but not the least, it is stated clearly:

The SearchFilter class supports simple single query parameter based searching, and is based on the Django admin's search functionality.

Thus it should also follow the lookups like admin site does.

[auvipy]

I checked your PR and I'm convinced that it could be a nice compat improvement 👯