use http2_push instead of http2_push_preload

This avoids needing to conditionally add nopush to each preloaded
resource in the Link header. There's also no support for pushing
JavaScript modules via http2_push_preload since nginx doesn't have
support for rel=modulepreload.

Author: thestinger

nginx/nginx.conf

@@ -91,15 +91,22 @@ http {
         default 0;
     }
 
-    map $nopush $preload_resources {
-        1 "<{{path|/main.css}}>; rel=preload; nopush; as=style; integrity={{integrity|/main.css}}, </fonts/roboto-v29-regular-latin.woff2>; rel=preload; nopush; as=font; crossorigin, </fonts/roboto-v29-bold-latin.woff2>; rel=preload; nopush; as=font; crossorigin";
-        default "<{{path|/main.css}}>; rel=preload; as=style; integrity={{integrity|/main.css}}, </fonts/roboto-v29-regular-latin.woff2>; rel=preload; as=font; crossorigin, </fonts/roboto-v29-bold-latin.woff2>; rel=preload; as=font; crossorigin";
-    }
-
     map $nopush $push_cookie {
         0 "__Host-preload=1; HttpOnly; Secure; SameSite=Lax; Path=/";
     }
 
+    map $nopush $push_stylesheet {
+        0 "{{path|/main.css}}";
+    }
+
+    map $nopush $push_font_regular {
+        0 /fonts/roboto-v29-regular-latin.woff2;
+    }
+
+    map $nopush $push_font_bold {
+        0 /fonts/roboto-v29-bold-latin.woff2;
+    }
+
     server {
         listen 80 backlog=4096;
         listen [::]:80 backlog=4096;

nginx/snippets/preload.conf

@@ -1,3 +1,5 @@
-add_header Link $preload_resources always;
+add_header Link "<{{path|/main.css}}>; rel=preload; as=style; integrity={{integrity|/main.css}}, </fonts/roboto-v29-regular-latin.woff2>; rel=preload; as=font; crossorigin, </fonts/roboto-v29-bold-latin.woff2>; rel=preload; as=font; crossorigin" always;
 add_header Set-Cookie $push_cookie always;
-http2_push_preload on;
+http2_push $push_stylesheet;
+http2_push $push_font_regular;
+http2_push $push_font_bold;

process-static

@@ -39,7 +39,7 @@ for file in static-tmp/**/*.css static-tmp/**/*.js; do
     replace+=";s@{{path|/${file#*/}}}@/${dest#*/}@g"
 done
 
-sed -i "$replace" static-tmp/**/*.html nginx-tmp/nginx.conf
+sed -i "$replace" static-tmp/**/*.html nginx-tmp/nginx.conf nginx-tmp/snippets/preload.conf
 
 gixy nginx-tmp/nginx.conf