Rename identifiers related to preload Link header to reflect curren…

…t Cloudflare behavior

HTTP/2 server push has been dropped by Cloudflare and all browsers.

weasyl/middleware.py

@@ -298,14 +298,9 @@ def cleanup(request):
     return database_session_cleanup_tween
 
 
-def _generate_http2_server_push_headers():
+def _generate_preload_link() -> str:
     """
-    Generates the Link headers to load HTTP/2 Server Push resources which are needed on each pageload. Written
-    as a separate function to only execute this code a single time, since we just need to generate this each
-    time the code is relaunched (e.g., each time the web workers are kicked to a new version of the code).
-
-    A component of ``http2_server_push_tween_factory``
-    :return: An ASCII encoded string to be loaded into the Link header set inside of ``http2_server_push_tween_factory``
+    Generates the `Link` header to preload resources needed on every webpage.
     """
     css_preload = [
         '<' + item + '>; rel=preload; as=style' for item in [
@@ -329,23 +324,22 @@ def _generate_http2_server_push_headers():
     return ", ".join(css_preload + js_preload + esm_preload)
 
 
-# Part of the `Link` header that will be set in the `http2_server_push_tween_factory` function, below
-HTTP2_LINK_HEADER_PRELOADS = _generate_http2_server_push_headers()
+# part of the `Link` header that will be set in the `preload_tween_factory` function below
+_WEBPAGE_PRELOADS_LINK = _generate_preload_link()
 
 
-def http2_server_push_tween_factory(handler, registry):
+def preload_tween_factory(handler, registry):
     """
-    Add the 'Link' header to outgoing responses to HTTP/2 Server Push render-blocking resources
+    Add the `Link` header to outgoing responses to preload resources needed on every webpage, which is served ahead of time by Cloudflare as an HTTP 103 Early Hints message.
     """
-    def http2_server_push(request):
+    def preload_tween(request):
         resp = handler(request)
 
         if resp.headers['Content-Type'].startswith("text/html"):
-            # Combined HTTP/2 headers indicating which resources to server push
-            resp.headers['Link'] = HTTP2_LINK_HEADER_PRELOADS
+            resp.headers['Link'] = _WEBPAGE_PRELOADS_LINK
 
         return resp
-    return http2_server_push
+    return preload_tween
 
 
 # Properties and methods to enhance the pyramid `request`.

weasyl/wsgi.py

@@ -27,7 +27,7 @@
 config.add_tween("weasyl.middleware.db_timer_tween_factory")
 config.add_tween("weasyl.middleware.cache_clear_tween_factory")
 config.add_tween("weasyl.middleware.database_session_cleanup_tween_factory")
-config.add_tween("weasyl.middleware.http2_server_push_tween_factory")
+config.add_tween("weasyl.middleware.preload_tween_factory")
 config.add_tween("weasyl.middleware.query_debug_tween_factory")
 config.add_tween("pyramid.tweens.excview_tween_factory")  # Required to catch exceptions thrown in tweens.
 config.add_tween("weasyl.middleware.utf8_path_tween_factory")