Source code for api.users.filters

from elasticsearch_dsl import Q
from rest_framework.filters import BaseFilterBackend
from rest_framework.settings import api_settings

from apps.users.documents import UserDocument




class UserElasticsearchFilter(BaseFilterBackend):
    """
    Filter for performing user search using Elasticsearch.
    Executes search on username, first_name, and last_name with different weights.
    """



    def construct_query(self, search_param):
        """
        Constructs a combined Elasticsearch query from various parts.

        :param search_param: The search parameter entered by the user.
        :return: A combined Elasticsearch query.
        """
        # Queries for each parameter
        username_query = Q("match", username={"query": search_param, "fuzziness": "AUTO", "boost": 4})
        first_name_query = Q("match", first_name={"query": search_param, "fuzziness": "AUTO", "boost": 3})
        last_name_query = Q("match", last_name={"query": search_param, "fuzziness": "AUTO", "boost": 2})

        # Combine the queries
        combined_query = Q(
            "bool",
            should=[
                username_query,
                first_name_query,
                last_name_query,
            ],
        )
        return combined_query




    def filter_queryset(self, request, queryset, view):
        """
        Filters a QuerySet based on the search parameters in the request.

        :param request: HTTP request object.
        :param queryset: Initial QuerySet.
        :param view: The view that calls this method.
        :return: Updated QuerySet.
        """
        search_param = request.query_params.get("search")
        offset = int(request.query_params.get("offset", 0))
        limit = int(request.query_params.get("limit", api_settings.PAGE_SIZE))
        if search_param:
            combined_query = self.construct_query(search_param)
            search = UserDocument.search().query(combined_query)
            total_results = search.count()
            if offset >= total_results:
                return queryset.none()
            end = offset + limit
            search = search[offset:end]
            queryset = search.to_queryset()
            queryset.search_count = total_results
        return queryset