perf(h5): 合并为单次 category-tree 接口 + 后端缓存

- 后端新增 /material/category-tree/ 一次性聚合 (大类→种类→子类)，使用 Django cache 全局缓存（30 分钟）
- Material post_save / post_delete 信号自动失效缓存，保证一致性
- H5 首页从 4 次并行请求降为 1 次；命中缓存时不打 DB

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/apps/material/apps.py

@@ -0,0 +1,9 @@
+from django.apps import AppConfig
+
+
+class MaterialConfig(AppConfig):
+    default_auto_field = 'django.db.models.BigAutoField'
+    name = 'apps.material'
+
+    def ready(self):
+        from . import signals  # noqa: F401

backend/apps/material/signals.py

@@ -0,0 +1,21 @@
+from django.core.cache import cache
+from django.db.models.signals import post_delete, post_save
+from django.dispatch import receiver
+
+from .models import Material
+
+CATEGORY_TREE_CACHE_KEY = 'material:category_tree:approved'
+
+
+def invalidate_category_tree_cache():
+    cache.delete(CATEGORY_TREE_CACHE_KEY)
+
+
+@receiver(post_save, sender=Material)
+def _on_material_saved(sender, instance, **kwargs):
+    invalidate_category_tree_cache()
+
+
+@receiver(post_delete, sender=Material)
+def _on_material_deleted(sender, instance, **kwargs):
+    invalidate_category_tree_cache()

backend/apps/material/views.py

@@ -15,9 +15,11 @@ from rest_framework.response import Response
 from rest_framework.viewsets import ModelViewSet
 from rest_framework.exceptions import PermissionDenied
 from rest_framework.parsers import MultiPartParser
+from django.core.cache import cache
 from .models import Material, MaterialCategory, MaterialSubcategory
 from .serializers import MaterialSerializer, MaterialListSerializer, MaterialCategorySerializer, MaterialSubcategorySerializer
 from .importers import import_materials_plan_excel
+from .signals import CATEGORY_TREE_CACHE_KEY
 from apps.factory.models import COOPERATION_MODE_CHOICES
 
 
@@ -484,6 +486,59 @@ class MaterialViewSet(ModelViewSet):
 
         return Response(result)
 
+    @action(detail=False, methods=['get'], url_path='category-tree', permission_classes=[IsAuthenticated])
+    def category_tree(self, request):
+        """
+        H5 浏览端的全量种类树：一次返回所有大类 → 材料种类 → 子类的聚合结果。
+        与用户无关（仅依赖 status='approved'），故走全局缓存；Material 变更时由 signals 失效。
+        """
+        cached = cache.get(CATEGORY_TREE_CACHE_KEY)
+        if cached is not None:
+            return Response(cached)
+
+        rows = (Material.objects
+                .filter(status='approved')
+                .exclude(major_category__isnull=True).exclude(major_category__exact='')
+                .exclude(material_category__isnull=True).exclude(material_category__exact='')
+                .values('major_category', 'material_category', 'material_subcategory')
+                .annotate(count=Count('id'))
+                .order_by('major_category', 'material_category', 'material_subcategory'))
+
+        majors = {}
+        for row in rows:
+            mj = row['major_category']
+            cat = row['material_category']
+            sub = row['material_subcategory'] or ''
+            cnt = row['count']
+
+            major_node = majors.setdefault(mj, {})
+            cat_node = major_node.setdefault(cat, {'count': 0, 'subs': {}})
+            cat_node['count'] += cnt
+            if sub:
+                cat_node['subs'][sub] = cat_node['subs'].get(sub, 0) + cnt
+
+        major_display = dict(Material.MAJOR_CATEGORY_CHOICES)
+        data = []
+        for mj_value, cats in majors.items():
+            data.append({
+                'value': mj_value,
+                'label': major_display.get(mj_value, mj_value),
+                'categories': [
+                    {
+                        'value': cat,
+                        'count': node['count'],
+                        'subcategories': [
+                            {'value': s, 'count': c}
+                            for s, c in sorted(node['subs'].items())
+                        ],
+                    }
+                    for cat, node in sorted(cats.items())
+                ],
+            })
+
+        cache.set(CATEGORY_TREE_CACHE_KEY, data, timeout=60 * 30)
+        return Response(data)
+
     @action(detail=False, methods=['get'], url_path='categories-by-major')
     def categories_by_major(self, request):
         major = request.query_params.get('major_category')

frontend-h5/src/api/material.js

@@ -2,6 +2,7 @@ import api from './client'
 
 export const fetchMaterials = async (params) => (await api.get('/material/', { params })).data
 export const fetchMaterialDetail = async (id) => (await api.get(`/material/${id}/`)).data
+export const fetchCategoryTree = async () => (await api.get('/material/category-tree/')).data
 export const fetchCategoriesByMajor = async (major_category) =>
   (await api.get('/material/categories-by-major/', { params: { major_category } })).data
 export const fetchSubcategoriesByCategory = async (major_category, material_category) =>

frontend-h5/src/views/Home.vue

@@ -1,60 +1,51 @@
 <script setup>
-import { ref, onMounted, computed, watch } from 'vue'
+import { ref, onMounted, computed } from 'vue'
 import { useRouter } from 'vue-router'
 import MajorCategoryCard from '@/components/MajorCategoryCard.vue'
 import CategoryCard from '@/components/CategoryCard.vue'
 import Skeleton from '@/components/Skeleton.vue'
 import { useAuthStore } from '@/store/auth'
 import { useUiStore } from '@/store/ui'
-import { fetchCategoriesByMajor } from '@/api/material'
+import { fetchCategoryTree } from '@/api/material'
 
 defineOptions({ name: 'Home' })
 const router = useRouter()
 const auth = useAuthStore()
 const ui = useUiStore()
 
-const majors = [
+const fallbackMajors = [
   { value: 'architecture', label: '建筑' },
   { value: 'landscape', label: '景观' },
   { value: 'equipment', label: '设备' },
   { value: 'decoration', label: '装修' },
 ]
 
+const tree = ref([])
+const loading = ref(true)
 const selected = ref(ui.selectedMajor)
-const categoriesByMajor = ref({})
-const loading = ref(false)
 
-const loadAll = async () => {
-  loading.value = true
-  try {
-    const results = await Promise.all(majors.map((m) => fetchCategoriesByMajor(m.value)))
-    const map = {}
-    majors.forEach((m, i) => { map[m.value] = results[i] })
-    categoriesByMajor.value = map
-  } finally { loading.value = false }
-}
+const majors = computed(() => {
+  if (!tree.value.length) return fallbackMajors
+  const order = ['architecture', 'landscape', 'equipment', 'decoration']
+  const map = Object.fromEntries(tree.value.map((n) => [n.value, n]))
+  return order.filter((v) => map[v]).map((v) => ({ value: v, label: map[v].label }))
+})
+
+const visibleGroups = computed(() => {
+  const list = tree.value.length ? tree.value : []
+  if (selected.value) return list.filter((g) => g.value === selected.value)
+  return list
+})
 
 const onSelect = (v) => {
   selected.value = selected.value === v ? '' : v
   ui.setMajor(selected.value)
 }
 
-const visibleGroups = computed(() => {
-  if (selected.value) {
-    return [{ major: majors.find((m) => m.value === selected.value), categories: categoriesByMajor.value[selected.value] || [] }]
-  }
-  return majors.map((m) => ({ major: m, categories: categoriesByMajor.value[m.value] || [] }))
-})
-
-watch(selected, (v) => {
-  if (v && !categoriesByMajor.value[v]) {
-    fetchCategoriesByMajor(v).then((r) => { categoriesByMajor.value = { ...categoriesByMajor.value, [v]: r } })
-  }
-})
-
 onMounted(async () => {
   if (!auth.user) { try { await auth.loadUser() } catch {} }
-  await loadAll()
+  try { tree.value = await fetchCategoryTree() }
+  finally { loading.value = false }
 })
 
 const goCategory = (major, c) => router.push({ name: 'CategoryDetail', params: { major, category: c.value } })
@@ -75,28 +66,23 @@ const onLogout = () => { auth.logout(); router.replace('/login') }
     </section>
 
     <section class="px-4 pb-6 space-y-5">
-      <div v-if="loading && !Object.keys(categoriesByMajor).length" class="grid grid-cols-2 gap-3">
+      <div v-if="loading" class="grid grid-cols-2 gap-3">
         <Skeleton v-for="n in 6" :key="n" class="h-14" />
       </div>
 
       <template v-else>
-        <div v-for="g in visibleGroups" :key="g.major.value">
+        <div v-if="!visibleGroups.length" class="py-10 text-center text-sm text-muted">暂无已审核材料</div>
+        <div v-for="g in visibleGroups" :key="g.value">
           <div class="flex items-center justify-between mb-2">
-            <div class="text-xs text-muted">{{ g.major.label }} · 材料种类</div>
+            <div class="text-xs text-muted">{{ g.label }} · 材料种类</div>
             <span class="text-[11px] text-muted tnum">{{ g.categories.length }} 类</span>
           </div>
-          <div v-if="g.categories.length" class="grid grid-cols-2 gap-3">
+          <div class="grid grid-cols-2 gap-3">
             <CategoryCard v-for="c in g.categories" :key="c.value" :value="c.value" :count="c.count"
-              @click="goCategory(g.major.value, c)" />
+              @click="goCategory(g.value, c)" />
           </div>
-          <div v-else class="py-6 text-center text-xs text-muted bg-white rounded-card">暂无已审核材料</div>
         </div>
       </template>
     </section>
   </div>
 </template>
-
-<style scoped>
-.fade-enter-active,.fade-leave-active{transition:all .2s ease}
-.fade-enter-from,.fade-leave-to{opacity:0;transform:translateY(-4px)}
-</style>