redefine how request probabilities are computed

tests/test_ecommerce.py

@@ -60,15 +60,15 @@ def test_crawl():
 
     subcategories = {
         "subCategories": [
-            {"url": subcategory_urls[0]},
-            {"url": subcategory_urls[1]},
+            {"url": subcategory_urls[0], "metadata": {"probability": 0.95}},
+            {"url": subcategory_urls[1], "metadata": {"probability": 0.78}},
         ],
     }
     nextpage = {"nextPage": {"url": nextpage_url}}
     items = {
         "items": [
-            {"url": item_urls[0]},
-            {"url": item_urls[1]},
+            {"url": item_urls[0], "metadata": {"probability": 0.99}},
+            {"url": item_urls[1], "metadata": {"probability": 0.83}},
         ],
     }
 
@@ -86,8 +86,10 @@ def test_crawl():
     assert len(requests) == 2
     assert requests[0].url == subcategory_urls[0]
     assert requests[0].callback == spider.parse_navigation
+    assert requests[0].priority == 95
     assert requests[1].url == subcategory_urls[1]
     assert requests[1].callback == spider.parse_navigation
+    assert requests[1].priority == 78
 
     # subcategories + nextpage
     navigation = ProductNavigation.from_dict(
@@ -102,6 +104,7 @@ def test_crawl():
     urls = {request.url for request in requests}
     assert urls == {*subcategory_urls, nextpage_url}
     assert all(request.callback == spider.parse_navigation for request in requests)
+    assert [request.priority for request in requests] == [100, 95, 78]
 
     # subcategories + nextpage + items
     navigation = ProductNavigation.from_dict(
@@ -120,6 +123,7 @@ def test_crawl():
             assert request.callback == spider.parse_product
         else:
             assert request.callback == spider.parse_navigation
+    assert [request.priority for request in requests] == [199, 183, 100, 95, 78]
 
     # nextpage + items
     navigation = ProductNavigation.from_dict(
@@ -137,6 +141,7 @@ def test_crawl():
     assert requests[1].callback == spider.parse_product
     assert requests[2].url == nextpage_url
     assert requests[2].callback == spider.parse_navigation
+    assert [request.priority for request in requests] == [199, 183, 100]
 
     # subcategories + items
     navigation = ProductNavigation.from_dict(
@@ -156,6 +161,7 @@ def test_crawl():
     assert requests[2].callback == spider.parse_navigation
     assert requests[3].url == subcategory_urls[1]
     assert requests[3].callback == spider.parse_navigation
+    assert [request.priority for request in requests] == [199, 183, 95, 78]
 
     # nextpage
     navigation = ProductNavigation.from_dict(
@@ -168,6 +174,7 @@ def test_crawl():
     assert len(requests) == 1
     assert requests[0].url == nextpage_url
     assert requests[0].callback == spider.parse_navigation
+    assert [request.priority for request in requests] == [100]
 
     # items
     navigation = ProductNavigation.from_dict(
@@ -182,6 +189,7 @@ def test_crawl():
     assert requests[0].callback == spider.parse_product
     assert requests[1].url == item_urls[1]
     assert requests[1].callback == spider.parse_product
+    assert [request.priority for request in requests] == [199, 183]
 
 
 @pytest.mark.parametrize(

zyte_spider_templates/spiders/base.py

@@ -1,11 +1,11 @@
 from importlib.metadata import version
-from typing import Any, Callable, Dict, Optional
+from typing import Any, Callable, Dict, Optional, Union
 
 import scrapy
 from pydantic import BaseModel, Field
 from scrapy.crawler import Crawler
 from scrapy.utils.url import parse_url
-from zyte_common_items import Request
+from zyte_common_items import ProbabilityRequest, Request
 
 from zyte_spider_templates._geolocations import (
     GEOLOCATION_OPTIONS_WITH_CODE,
@@ -57,7 +57,7 @@ class BaseSpider(scrapy.Spider):
         "description": "Base template.",
     }
 
-    ITEM_REQUEST_PRIORITY: int = 10
+    _NEXT_PAGE_PRIORITY: int = 100
 
     @classmethod
     def from_crawler(cls, crawler: Crawler, *args, **kwargs) -> scrapy.Spider:
@@ -86,18 +86,20 @@ def from_crawler(cls, crawler: Crawler, *args, **kwargs) -> scrapy.Spider:
         return spider
 
     @staticmethod
-    def get_parse_navigation_request_priority(request: Request) -> int:
+    def get_parse_navigation_request_priority(
+        request: Union[ProbabilityRequest, Request]
+    ) -> int:
         if (
             not hasattr(request, "metadata")
             or not request.metadata
             or request.metadata.probability is None
         ):
             return 0
-        return int(10 * request.metadata.probability)
+        return int(100 * request.metadata.probability)
 
     def get_parse_navigation_request(
         self,
-        request: Request,
+        request: Union[ProbabilityRequest, Request],
         callback: Optional[Callable] = None,
         page_params: Optional[Dict[str, Any]] = None,
         priority: Optional[int] = None,
@@ -109,11 +111,15 @@ def get_parse_navigation_request(
             meta={"page_params": page_params or {}},
         )
 
-    def get_parse_product_request_priority(self, request: Request) -> int:
-        return self.ITEM_REQUEST_PRIORITY
+    def get_parse_product_request_priority(self, request: ProbabilityRequest) -> int:
+        # TODO: Simplify when https://github.com/zytedata/zyte-common-items/pull/64 is released
+        probability = 0
+        if metadata := getattr(request, "metadata", None):
+            probability = metadata.probability
+        return int(100 * probability) + self._NEXT_PAGE_PRIORITY
 
     def get_parse_product_request(
-        self, request: Request, callback: Optional[Callable] = None
+        self, request: ProbabilityRequest, callback: Optional[Callable] = None
     ) -> scrapy.Request:
         callback = callback or self.parse_product
         return request.to_scrapy(

zyte_spider_templates/spiders/ecommerce.py

@@ -133,7 +133,7 @@ def parse_navigation(
         if navigation.nextPage:
             yield self.get_parse_navigation_request(
                 navigation.nextPage,
-                priority=self.ITEM_REQUEST_PRIORITY - 1,
+                priority=self._NEXT_PAGE_PRIORITY,
             )
         for request in navigation.subCategories or []:
             if "[heuristics]" in (request.name or ""):