Merge pull request #293 from PROCOLLAB-github/dev

Лента, оценки и куча куча багов

Author: yakser

feed/constants.py

@@ -1,9 +1,13 @@
 import enum
 
+from django.db.models import QuerySet
 from rest_framework import serializers
 
-from news.serializers import NewsListSerializer
+from news.models import News
+from news.serializers import NewsFeedListSerializer
+from projects.models import Project
 from projects.serializers import ProjectListSerializer
+from vacancy.models import Vacancy
 from vacancy.serializers import VacancyDetailSerializer
 
 
@@ -15,6 +19,17 @@ class FeedItemType(enum.Enum):
 
 FEED_SERIALIZER_MAPPING: dict[FeedItemType, serializers.Serializer] = {
     FeedItemType.PROJECT.value: ProjectListSerializer,
-    FeedItemType.NEWS.value: NewsListSerializer,
+    FeedItemType.NEWS.value: NewsFeedListSerializer,
     FeedItemType.VACANCY.value: VacancyDetailSerializer,
 }
+
+SupportedModel = News | Project | Vacancy
+SupportedQuerySet = QuerySet[News | Project | Vacancy]
+
+model_mapping = {
+    FeedItemType.NEWS.value: News,
+    FeedItemType.PROJECT.value: Project,
+    FeedItemType.VACANCY.value: Vacancy,
+}
+
+LIMIT_PAGINATION_CONSTANT = 10

feed/helpers.py

@@ -1,30 +1,143 @@
-import random
-import typing
+from random import shuffle
+from typing import Iterable
+
+from rest_framework.request import Request
+from rest_framework.views import APIView
 
 from feed import constants
+from feed.constants import (
+    SupportedModel,
+    SupportedQuerySet,
+    LIMIT_PAGINATION_CONSTANT
+)
+from feed.pagination import FeedPagination
 from feed.serializers import FeedItemSerializer
+from news.models import News
 from projects.models import Project
 
+from django.db.models import Count
 
-def collect_feed(models_list: typing.List, num) -> list[dict]:
-    get_model_data = {
-        model.__name__: collect_querysets(model, num) for model in models_list
-    }
+from vacancy.models import Vacancy
+
+
+def add_pagination(results: list[SupportedQuerySet], count: int) -> dict:
+    return {"count": count, "previous": None, "next": None, "results": results}
+
+
+def paginate_serialize_feed(
+    model_data: dict[SupportedQuerySet],
+    paginator: FeedPagination,
+    request: Request,
+    view: APIView,
+) -> tuple[list[SupportedQuerySet], int]:
     result = []
-    for model in get_model_data:
-        result.extend(to_feed_items(model, get_model_data[model]))
-    random.shuffle(result)
-    return result
+    pages_count = 0
+
+    if len(model_data) == 0:
+        return [], 0
 
+    offset = request.query_params.get("offset", 0)
+    request.query_params._mutable = True
 
-def collect_querysets(model, num):
-    if model.__name__ == Project.__class__.__name__:
-        return set(get_n_random_projects(num) + get_n_latest_created_projects(num))
+    if isinstance(offset, str) and offset.isdigit():
+        offset = int(offset)
     else:
-        return list(model.objects.order_by("-datetime_created")[:num])
+        offset = 0
+
+    request.query_params["offset"] = offset
+
+    models_counts = {
+        model_name: model_data[model_name].count() for model_name in model_data.keys()
+    }
+    offset_numbers = offset_distribution(offset, models_counts)
+
+    for model_name in model_data.keys():
+        request.query_params["offset"] = offset_numbers[model_name]
+
+        paginated_part: dict = paginate_serialize_feed_queryset(
+            model_data, paginator, request, model_name, models_counts[model_name], view
+        )
+
+        result += paginated_part["paginated_data"]
+        pages_count += paginated_part["page_count"]
+
+    limit = request.query_params.get("limit", LIMIT_PAGINATION_CONSTANT)
+
+    if limit == "":
+        limit = LIMIT_PAGINATION_CONSTANT
+    else:
+        limit = int(limit)
+
+    shuffle(result)
+    return result[:limit], pages_count
 
 
-def to_feed_items(type_: constants.FeedItemType, items: typing.Iterable) -> list[dict]:
+def offset_distribution(offset: int, models_counts: dict) -> dict:
+    common_key_list = list(models_counts.keys())
+    quantity_of_models = len(list(models_counts.keys()))
+
+    full_division = offset // quantity_of_models
+    extra_items = offset % quantity_of_models
+
+    distributed_not_ready = {model_name: full_division for model_name in common_key_list}
+    distributed = dict(
+        sorted(distributed_not_ready.items(), key=lambda item: models_counts[item[0]])
+    )
+
+    last_key = common_key_list[-1]
+    distributed[last_key] += extra_items
+
+    new_keys_list = list(distributed.keys())
+    for i, key in enumerate(
+        new_keys_list
+    ):  # распределяем переполненные значения от маленьких моделей к большим
+        offset_value = distributed[key]
+        model_count = models_counts[key]
+        if offset_value > model_count:
+            diff = offset_value - model_count
+            distributed[key] = model_count
+            if i + 1 < len(new_keys_list):
+                next_key = new_keys_list[i + 1]
+                distributed[next_key] += diff
+
+    return distributed
+
+
+def paginate_serialize_feed_queryset(
+    model_data: dict[SupportedQuerySet],
+    paginator: FeedPagination,
+    request: Request,
+    model: SupportedModel,
+    count: int,
+    view: APIView,
+) -> dict:
+    paginated_info = paginator.custom_paginate_queryset(
+        model_data[model], request, count, view=view
+    )
+    paginated_data = paginated_info["queryset_ready"]
+    num_pages = paginated_info["count"]
+    return {
+        "paginated_data": to_feed_items(model, paginated_data),
+        "page_count": num_pages,
+    }
+
+
+def collect_querysets(model: SupportedModel) -> SupportedQuerySet:
+    if model == Project:
+        queryset = model.objects.select_related("leader", "industry").filter(draft=False)
+    elif model == Vacancy:
+        queryset = model.objects.select_related("project")
+    elif model == News:
+        queryset = (
+            model.objects.select_related("content_type")
+            .prefetch_related("content_object", "files")
+            .annotate(likes_count=Count("likes"), views_count=Count("views"))
+        )
+
+    return queryset.order_by("-datetime_created")
+
+
+def to_feed_items(type_: constants.FeedItemType, items: Iterable) -> list[dict]:
     feed_items = []
     for item in items:
         serializer = to_feed_item(type_, item)
@@ -33,14 +146,6 @@ def to_feed_items(type_: constants.FeedItemType, items: typing.Iterable) -> list
     return feed_items
 
 
-def get_n_random_projects(num: int) -> list[Project]:
-    return list(Project.objects.filter(draft=False).order_by("?").distinct()[:num])
-
-
-def get_n_latest_created_projects(num: int) -> list[Project]:
-    return list(Project.objects.filter(draft=False).order_by("-datetime_created")[:num])
-
-
 def to_feed_item(type_: constants.FeedItemType, data):
     serializer = constants.FEED_SERIALIZER_MAPPING[type_](data)
-    return FeedItemSerializer(data={"type": type_, "content": serializer.data})
+    return FeedItemSerializer(data={"type_model": type_, "content": serializer.data})

feed/pagination.py

@@ -0,0 +1,32 @@
+from rest_framework import pagination
+from rest_framework.request import Request
+
+from feed.constants import SupportedQuerySet
+
+
+class FeedPagination(pagination.LimitOffsetPagination):
+    default_limit = 10
+    limit_query_param = "limit"
+    offset_query_param = "offset"
+
+    def custom_paginate_queryset(
+        self, queryset: SupportedQuerySet, request: Request, count: int, view=None
+    ) -> dict:
+        self.limit = self.get_limit(request)
+        if self.limit is None:
+            return None
+
+        self.count = count
+        self.offset = self.get_offset(request)
+        self.request = request
+        if self.count > self.limit and self.template is not None:
+            self.display_page_controls = True
+
+        if self.count == 0 or self.offset > self.count:
+            return {"queryset_ready": [], "count": self.count}
+
+        queryset_ready = queryset[self.offset : self.offset + self.limit]  # noqa: E203
+        return {
+            "queryset_ready": queryset_ready,
+            "count": self.count,
+        }

feed/serializers.py

@@ -3,5 +3,5 @@
 
 
 class FeedItemSerializer(serializers.Serializer):
-    type = serializers.ChoiceField(choices=constants.FeedItemType, required=True)
+    type_model = serializers.ChoiceField(choices=constants.FeedItemType, required=True)
     content = serializers.JSONField(required=True)

feed/views.py

@@ -5,13 +5,14 @@
 from rest_framework.response import Response
 from rest_framework.views import APIView
 
-from feed.helpers import collect_feed
-from news.models import News
-from projects.models import Project
-from vacancy.models import Vacancy
+from feed.constants import SupportedModel, SupportedQuerySet, FeedItemType, model_mapping
+from feed.helpers import collect_querysets, paginate_serialize_feed, add_pagination
+from feed.pagination import FeedPagination
 
 
 class FeedList(APIView):
+    pagination_class = FeedPagination
+
     @swagger_auto_schema(
         responses={
             200: openapi.Response(
@@ -31,13 +32,34 @@ class FeedList(APIView):
         }
     )
     def get(self, request: Request, *args, **kwargs) -> Response:
-        models = []
-        filter = request.query_params.get("type")
-        if "news" in filter:
-            models.append(News)
-        if "project" in filter:
-            models.append(Project)
-        if "vacancy" in filter:
-            models.append(Vacancy)
-
-        return Response(status=status.HTTP_200_OK, data=collect_feed(models, 3))
+        prepared_data, sum_pages = self.paginate_serialize_data(
+            self.get_response_data(self.get_request_data())
+        )
+        for obj in prepared_data:
+            obj["type_model"] = obj["type_model"].lower()
+        return Response(
+            status=status.HTTP_200_OK,
+            data=add_pagination(prepared_data, sum_pages),
+        )
+
+    def get_request_data(self) -> list[SupportedModel]:
+        filter_queries = self.request.query_params.get("type")
+        filter_queries = filter_queries if filter_queries else ""  # existence check
+
+        models = [
+            model_mapping[model_name]
+            for model_name in model_mapping.keys()
+            if model_name.lower() in filter_queries
+        ]
+        return models
+
+    def get_response_data(
+        self, models: list[SupportedModel]
+    ) -> dict[FeedItemType, SupportedQuerySet]:
+        return {model.__name__: collect_querysets(model) for model in models}
+
+    def paginate_serialize_data(
+        self, get_model_data: dict[FeedItemType, SupportedQuerySet]
+    ) -> tuple[list[dict], int]:
+        paginator = self.pagination_class()
+        return paginate_serialize_feed(get_model_data, paginator, self.request, self)

news/serializers.py

@@ -1,10 +1,15 @@
 from django.contrib.auth import get_user_model
+from django.forms import model_to_dict
 from rest_framework import serializers
 
 from core.services import is_fan, get_likes_count, get_views_count
 from files.serializers import UserFileSerializer
 from news.mapping import NewsMapping
 from news.models import News
+from projects.models import Project
+from projects.serializers import ProjectListSerializer
+from users.models import CustomUser
+from users.serializers import UserFeedSerializer
 
 User = get_user_model()
 
@@ -59,6 +64,56 @@ class Meta:
         ]
 
 
+class NewsFeedListSerializer(serializers.ModelSerializer):
+    name = serializers.SerializerMethodField()
+    image_address = serializers.SerializerMethodField()
+    is_user_liked = serializers.SerializerMethodField()
+    files = UserFileSerializer(many=True)
+    views_count = serializers.IntegerField(default=0)
+    likes_count = serializers.IntegerField(default=0)
+    content_object = serializers.SerializerMethodField()
+
+    def get_content_object(self, obj):
+        if obj.content_type.model == Project.__name__.lower():
+            serialized_obj = ProjectListSerializer(instance=obj.content_object, data={})
+            serialized_obj.is_valid()
+            return serialized_obj.data
+        elif obj.content_type.model == CustomUser.__name__.lower():
+            serialized_obj = UserFeedSerializer(
+                instance=obj.content_object, data=model_to_dict(obj.content_object)
+            )
+            serialized_obj.is_valid()
+            return serialized_obj.data
+
+    def get_name(self, obj):
+        return NewsMapping.get_name(obj.content_object)
+
+    def get_image_address(self, obj):
+        return NewsMapping.get_image_address(obj.content_object)
+
+    def get_is_user_liked(self, obj):
+        user = self.context.get("user")
+        if user:
+            return is_fan(obj, user)
+        return False
+
+    class Meta:
+        model = News
+        fields = [
+            "id",
+            "name",
+            "image_address",
+            "text",
+            "datetime_created",
+            "views_count",
+            "likes_count",
+            "files",
+            "is_user_liked",
+            "content_object",
+        ]
+        read_only_fields = ["views_count", "likes_count"]
+
+
 class NewsDetailSerializer(serializers.ModelSerializer):
     views_count = serializers.SerializerMethodField()
     likes_count = serializers.SerializerMethodField()