Use serializer to validate search params

website/search/models.py

@@ -1,6 +1,7 @@
-from django.core.paginator import EmptyPage, PageNotAnInteger, Paginator
+from django.core.paginator import EmptyPage, Paginator
 from django.http.request import HttpRequest
 from django.utils.functional import cached_property
+from rest_framework import serializers
 from wagtail.models import Page
 from wagtail.query import PageQuerySet
 from wagtail.search.models import Query
@@ -19,6 +20,10 @@ class SearchPage(BaseContentMixin, BasePage):  # type: ignore[misc]
     search_fields = BasePage.search_fields + BaseContentMixin.search_fields
     PAGE_SIZE = 15
 
+    class SearchParamsSerializer(serializers.Serializer):
+        q = serializers.CharField()
+        page = serializers.IntegerField(min_value=1, default=1)
+
     @cached_property
     def reading_time(self) -> int:
         """
@@ -35,29 +40,36 @@ class SearchPage(BaseContentMixin, BasePage):  # type: ignore[misc]
 
     def get_context(self, request: HttpRequest) -> dict:
         context = super().get_context(request)
-        if query_string := request.GET.get("q", ""):
-            filters, query = parse_query_string(query_string)
-            Query.get(query_string).add_hit()
+
+        serializer = self.SearchParamsSerializer(data=request.GET)
+
+        if serializer.is_valid():
+            search_query = serializer.validated_data["q"]
+            filters, query = parse_query_string(search_query)
+            Query.get(search_query).add_hit()
             pages = self.get_search_pages().search(query)
+
+            paginator = Paginator(pages, self.PAGE_SIZE)
+            context["paginator"] = paginator
+            page_num = serializer.validated_data["page"]
+            context["page_num"] = page_num
+            try:
+                results = paginator.page(page_num)
+
+                # HACK: Search results aren't a queryset, so we can't call `.specific` on it. This forces it to one as efficiently as possible
+                if not isinstance(results.object_list, PageQuerySet):
+                    results.object_list = Page.objects.filter(
+                        id__in=list(
+                            results.object_list.get_queryset().values_list(
+                                "id", flat=True
+                            )
+                        )
+                    ).specific()
+            except EmptyPage:
+                results = []
+
+            context["results"] = results
         else:
-            pages = Page.objects.none()
-
-        paginator = Paginator(pages, self.PAGE_SIZE)
-        page_num = request.GET.get("page", "1")
-        try:
-            results = paginator.page(page_num)
-
-            # HACK: Search results aren't a queryset, so we can't call `.specific` on it. This forces it to one as efficiently as possible
-            if not isinstance(results.object_list, PageQuerySet):
-                results.object_list = Page.objects.filter(
-                    id__in=list(
-                        results.object_list.get_queryset().values_list("id", flat=True)
-                    )
-                ).specific()
-        except (PageNotAnInteger, EmptyPage):
-            results = None
-            context["invalid_page"] = True
-
-        context["results"] = results
+            context["invalid_search"] = True
 
         return context

website/search/templates/search/search_page.html

@@ -11,8 +11,14 @@
 {% endif %}
 
 <section class="container">
-  {% if invalid_page %}
-    <p>Invalid page</p>
+  {% if invalid_search %}
+    <p>Invalid search</p>
+  {% elif results|length == 0 %}
+    {% if page_num > paginator.num_pages %}
+      <p>There aren't {{ page_num }} page - only {{ paginator.num_pages }}.</p>
+    {% else %}
+      <p>No results</p>
+    {% endif %}
   {% else %}
     {% for page in results %}
       {% include "common/listing-item.html" %}