Simple customized filter names for django-rest-framework (DRF)

filters.py

from django.template import loader, Template, Context
from rest_framework.filters import SearchFilter


browsable_api_filter_template = """{% load i18n %}
<h2>{{ title }}</h2>
<p>{{description}}</p>
<form class="form-inline">
  <div class="form-group">
    <div class="input-group">
      <input type="text" class="form-control" style="width: 350px" name="{{ param }}" value="{{ term }}">
      <span class="input-group-btn">
        <button class="btn btn-default" type="submit"><span class="glyphicon glyphicon-search" aria-hidden="true"></span> Filter</button>
      </span>
    </div>
  </div>
</form>
"""

def __to_html(self, request, queryset, view):
    """
    Redefined method does not require
    search_fields field to exist in APIView
    to render filters for browsable API
    """

    term = self.get_search_terms(request)
    term = term[0] if term else ''
    context = Context({
        'param': self.search_param,
        'term': term,
        # add title and description to recognize filters in web interface
        'title': self.search_title,
        'description': self.search_description
    })
    template = Template(browsable_api_filter_template)

    return template.render(context)


def named_filter(
        search_field_name,
        search_fields,
        search_title=None,
        search_description=None):
    """
    Dynamically creates and returns customized SearchFilter class
    with custom search_param name

    Use with APIView for filtering results with custom
    parameter name.

    E.g.

    class UserListView(generics.ListAPIView):
        queryset = User.objects.all()
        serializer_class = UserSerializer
        filter_backends = [named_filter(
                                'email',
                                ['=email'],
                                "Email",
                                "Find user by specific email"
                            )]

        # lets you filter by email parameter like this:
        # url?email=some@example.com


    Note: may break browsable API search when used.

    :param search_field_name: name of the search field in URL params
    :param search_fields: fields to search,
    see https://www.django-rest-framework.org/api-guide/filtering/#searchfilter
    :param search_description: verbose search description
    :param search_title: verbose search title
    :return:
    """

    if not search_title:
        search_title = search_field_name

    if not search_description:
        search_description = f"Filters results by {search_field_name}"

    return type(f"{search_field_name}Filter", (SearchFilter,), {
        "search_param": search_field_name,
        "get_search_fields": lambda self, view, request: search_fields,
        "to_html": __to_html,
        "search_title": search_title,
        "search_description": search_description
    })

Based on SearchFilter included in DRF

Usage:

class UserListView(generics.ListAPIView):
        queryset = User.objects.all()
        serializer_class = UserSerializer
        filter_backends = [named_filter(
                                'email',
                                ['=email'],
                                "Email",
                                "Find user by specific email"
                            )]
        # lets you filter by email parameter like this:
        # url?email=some@example.com

You can have as many filters at the same time as you want.
Schema generation works.

tested with DRF 3.10