Phase 4: replace container widgets with fragment fetches

Blog post page and home route fetch container-nav from events + market
concurrently via fetch_fragments(). Blog listing fetches container-cards
from events and parses per-post HTML via comment markers.
widget_paginate proxies calendar pagination to events fragment.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

bp/blog/routes.py

@@ -85,7 +85,7 @@ def register(url_prefix, title):
       from shared.config import config as get_config
       from shared.infrastructure.cart_identity import current_cart_identity
       from shared.services.registry import services as svc
-      from shared.services.widget_registry import widgets
+      from shared.infrastructure.fragments import fetch_fragment, fetch_fragments
 
       p_data = await _post_data("home", g.s, include_drafts=False)
       if not p_data:
@@ -98,23 +98,27 @@ def register(url_prefix, title):
       db_post_id = p_data["post"]["id"]
       post_slug = p_data["post"]["slug"]
 
-      container_nav_loaded = []
-      for w in widgets.container_nav:
-          try:
-              wctx = await w.context_fn(
-                  g.s, container_type="page", container_id=db_post_id,
-                  post_slug=post_slug,
-              )
-              has_data = any(v for v in wctx.values() if isinstance(v, list) and v)
-              if has_data:
-                  container_nav_loaded.append({"widget": w, "ctx": wctx})
-          except Exception:
-              pass
+      # Fetch container nav fragments from events + market
+      paginate_url = url_for(
+          'blog.post.widget_paginate',
+          slug=post_slug, widget_domain='calendar',
+      )
+      nav_params = {
+          "container_type": "page",
+          "container_id": str(db_post_id),
+          "post_slug": post_slug,
+          "paginate_url": paginate_url,
+      }
+      events_nav_html, market_nav_html = await fetch_fragments([
+          ("events", "container-nav", nav_params),
+          ("market", "container-nav", nav_params),
+      ])
+      container_nav_html = events_nav_html + market_nav_html
 
       ctx = {
           **p_data,
           "base_title": f"{get_config()['title']} {p_data['post']['title']}",
-          "container_nav_widgets": container_nav_loaded,
+          "container_nav_html": container_nav_html,
       }
 
       # Page cart badge

bp/blog/services/posts_data.py

@@ -1,7 +1,9 @@
+import re
+
 from ..ghost_db import DBClient  # adjust import path
 from sqlalchemy import select
 from models.ghost_content import PostLike
-from shared.services.widget_registry import widgets
+from shared.infrastructure.fragments import fetch_fragment
 from quart import g
 
 async def posts_data(
@@ -85,11 +87,16 @@ async def posts_data(
       for post in posts:
           post["is_liked"] = False
 
-  # Widget-driven card decoration
-  for w in widgets.container_cards:
-      batch_data = await w.batch_fn(session, post_ids)
-      for post in posts:
-          post[w.context_key] = batch_data.get(post["id"], [])
+  # Fetch card decoration fragments from events
+  card_widgets_html = {}
+  if post_ids:
+      post_slugs = [p.get("slug", "") for p in posts]
+      cards_html = await fetch_fragment("events", "container-cards", params={
+          "post_ids": ",".join(str(pid) for pid in post_ids),
+          "post_slugs": ",".join(post_slugs),
+      })
+      if cards_html:
+          card_widgets_html = _parse_card_fragments(cards_html)
 
   tags=await client.list_tags(
     limit=50000
@@ -113,4 +120,23 @@ async def posts_data(
       "draft_count": draft_count,
       "tag_groups": tag_groups,
       "selected_groups": selected_groups,
+      "card_widgets_html": card_widgets_html,
   }
+
+
+# Regex to extract per-post blocks delimited by comment markers
+_CARD_MARKER_RE = re.compile(
+    r'<!-- card-widget:(\d+) -->(.*?)<!-- /card-widget:\1 -->',
+    re.DOTALL,
+)
+
+
+def _parse_card_fragments(html: str) -> dict[str, str]:
+    """Parse the container-cards fragment into {post_id_str: html} dict."""
+    result = {}
+    for m in _CARD_MARKER_RE.finditer(html):
+        post_id_str = m.group(1)
+        inner = m.group(2).strip()
+        if inner:
+            result[post_id_str] = inner
+    return result

bp/post/routes.py

@@ -13,7 +13,7 @@ from quart import (
 from .services.post_data import post_data
 from .services.post_operations import toggle_post_like
 from shared.services.registry import services
-from shared.services.widget_registry import widgets
+from shared.infrastructure.fragments import fetch_fragment, fetch_fragments
 
 from shared.browser.app.redis_cacher import cache_page, clear_cache
 
@@ -69,24 +69,27 @@ def register():
           db_post_id = (g.post_data.get("post") or {}).get("id")
           post_slug = (g.post_data.get("post") or {}).get("slug", "")
 
-          # Widget-driven container nav
-          container_nav_loaded = []
-          for w in widgets.container_nav:
-              try:
-                  wctx = await w.context_fn(
-                      g.s, container_type="page", container_id=db_post_id,
-                      post_slug=post_slug,
-                  )
-                  has_data = any(v for v in wctx.values() if isinstance(v, list) and v)
-                  if has_data:
-                      container_nav_loaded.append({"widget": w, "ctx": wctx})
-              except Exception:
-                  pass
+          # Fetch container nav fragments from events + market
+          paginate_url = url_for(
+              'blog.post.widget_paginate',
+              slug=post_slug, widget_domain='calendar',
+          )
+          nav_params = {
+              "container_type": "page",
+              "container_id": str(db_post_id),
+              "post_slug": post_slug,
+              "paginate_url": paginate_url,
+          }
+          events_nav_html, market_nav_html = await fetch_fragments([
+              ("events", "container-nav", nav_params),
+              ("market", "container-nav", nav_params),
+          ])
+          container_nav_html = events_nav_html + market_nav_html
 
           ctx = {
               **p_data,
               "base_title": f"{config()['title']} {p_data['post']['title']}",
-              "container_nav_widgets": container_nav_loaded,
+              "container_nav_html": container_nav_html,
           }
 
           # Page cart badge via service
@@ -154,20 +157,22 @@ def register():
 
   @bp.get("/w/<widget_domain>/")
   async def widget_paginate(slug: str, widget_domain: str):
-      """Generic paginated widget endpoint for infinite scroll."""
+      """Proxies paginated widget requests to the appropriate fragment provider."""
       page = int(request.args.get("page", 1))
       post_id = g.post_data["post"]["id"]
 
-      for w in widgets.container_nav:
-          if w.domain == widget_domain:
-              ctx = await w.context_fn(
-                  g.s, container_type="page", container_id=post_id,
-                  post_slug=slug, page=page,
-              )
-              html = await render_template(
-                  w.template, ctx=ctx, post=g.post_data["post"],
-              )
-              return await make_response(html)
+      if widget_domain == "calendar":
+          html = await fetch_fragment("events", "container-nav", params={
+              "container_type": "page",
+              "container_id": str(post_id),
+              "post_slug": slug,
+              "page": str(page),
+              "paginate_url": url_for(
+                  'blog.post.widget_paginate',
+                  slug=slug, widget_domain='calendar',
+              ),
+          })
+          return await make_response(html or "")
       abort(404)
 
   return bp