From 233ce108693014fae4393632f8dcc2660db99707 Mon Sep 17 00:00:00 2001
From: Manuel Strehl <git@manuel-strehl.de>
Date: Fri, 1 Mar 2024 01:12:04 +0100
Subject: [PATCH] send rel=preload link headers

---
 codepoints.net/lib/Controller/Block.php       |  8 +++++++
 codepoints.net/lib/Controller/Codepoint.php   |  4 ++++
 codepoints.net/lib/Controller/Index.php       |  8 +++++++
 codepoints.net/lib/Controller/StaticPage.php  |  5 ++++
 .../lib/Controller/TraitPreload.php           | 24 +++++++++++++++++++
 codepoints.net/lib/view_functions.php         |  2 +-
 6 files changed, 50 insertions(+), 1 deletion(-)
 create mode 100644 codepoints.net/lib/Controller/TraitPreload.php

diff --git a/codepoints.net/lib/Controller/Block.php b/codepoints.net/lib/Controller/Block.php
index b534aa26..695e4e94 100644
--- a/codepoints.net/lib/Controller/Block.php
+++ b/codepoints.net/lib/Controller/Block.php
@@ -3,6 +3,7 @@
 namespace Codepoints\Controller;
 
 use Codepoints\Controller;
+use Codepoints\Controller\TraitPreload;
 use Codepoints\Router\NotFoundException;
 use Codepoints\Router\Pagination;
 use Codepoints\Unicode\Block as UnicodeBlock;
@@ -10,10 +11,17 @@
 
 class Block extends Controller {
 
+    use TraitPreload;
+
     /**
      * @param Array $data
      */
     public function __invoke($data, Array $env) : string {
+        $this->sendPreloadHeaders([
+            /* TODO preloading SVGs for <use> is not yet supported:
+             * https://github.com/whatwg/html/issues/8870 */
+            #sprintf('<%s>; rel=preload; as=image', static_url('images/LastResort.svg')),
+        ]);
         $block = new UnicodeBlock($data, $env['db']);
         $page = get_page();
 
diff --git a/codepoints.net/lib/Controller/Codepoint.php b/codepoints.net/lib/Controller/Codepoint.php
index 29383adb..5164d85b 100644
--- a/codepoints.net/lib/Controller/Codepoint.php
+++ b/codepoints.net/lib/Controller/Codepoint.php
@@ -3,6 +3,7 @@
 namespace Codepoints\Controller;
 
 use Codepoints\Controller;
+use Codepoints\Controller\TraitPreload;
 use Codepoints\Router\NotFoundException;
 use Codepoints\Unicode\Codepoint as UnicodeCodepoint;
 use Codepoints\Unicode\CodepointInfo\Aliases;
@@ -24,7 +25,10 @@
 
 class Codepoint extends Controller {
 
+    use TraitPreload;
+
     public function __invoke($match, Array $env) : string {
+        $this->sendPreloadHeaders();
         new Aliases($env);
         new CLDR($env);
         new CSUR($env);
diff --git a/codepoints.net/lib/Controller/Index.php b/codepoints.net/lib/Controller/Index.php
index 92076e0c..2ecba4be 100644
--- a/codepoints.net/lib/Controller/Index.php
+++ b/codepoints.net/lib/Controller/Index.php
@@ -3,12 +3,20 @@
 namespace Codepoints\Controller;
 
 use Codepoints\Controller;
+use Codepoints\Controller\TraitPreload;
 use Codepoints\Unicode\Codepoint;
+use Codepoints\View;
 
 
 class Index extends Controller {
 
+    use TraitPreload;
+
     public function __invoke($match, Array $env) : string {
+        $this->sendPreloadHeaders([
+            sprintf('<%s>; rel=preload; as=image', static_url('src/images/front_light.webp')),
+            sprintf('<%s>; rel=preload; as=image', static_url('src/images/front_dark.webp')),
+        ]);
         /** @var array */
         $data = $env['db']->getOne('SELECT cp, name, gc
             FROM codepoints
diff --git a/codepoints.net/lib/Controller/StaticPage.php b/codepoints.net/lib/Controller/StaticPage.php
index 5e046441..b4619d9e 100644
--- a/codepoints.net/lib/Controller/StaticPage.php
+++ b/codepoints.net/lib/Controller/StaticPage.php
@@ -3,15 +3,20 @@
 namespace Codepoints\Controller;
 
 use Codepoints\Controller;
+use Codepoints\Controller\TraitPreload;
 use Codepoints\Router\NotFoundException;
 use Codepoints\View;
 
 
 class StaticPage extends Controller {
+
+    use TraitPreload;
+
     /**
      * @param string $view
      */
     public function __invoke($view, Array $env) : string {
+        $this->sendPreloadHeaders();
         switch ($view) {
         case 'about':
             $data = $env['db']->getOne('SELECT COUNT(*) AS c FROM codepoints USE INDEX (PRIMARY)');
diff --git a/codepoints.net/lib/Controller/TraitPreload.php b/codepoints.net/lib/Controller/TraitPreload.php
new file mode 100644
index 00000000..74ec2799
--- /dev/null
+++ b/codepoints.net/lib/Controller/TraitPreload.php
@@ -0,0 +1,24 @@
+<?php
+
+namespace Codepoints\Controller;
+
+
+trait TraitPreload {
+
+    private function sendPreloadHeaders(Array $additional=[]) : void {
+        $headers = array_merge([
+            sprintf('<%s>; rel=preload; as=style; fetchpriority=high', static_url('src/css/main.css')),
+            sprintf('<%s>; rel=preload; as=font; fetchpriority=high; crossorigin=anonymous', static_url('src/fonts/Literata.woff2')),
+            sprintf('<%s>; rel=preload; as=font; fetchpriority=high; crossorigin=anonymous', static_url('src/fonts/Literata-Italic.woff2')),
+            sprintf('<%s>; rel=preload; as=style; fetchpriority=low', static_url('src/css/print.css')),
+            /* TODO preloading SVGs for <use> is not yet supported:
+             * https://github.com/whatwg/html/issues/8870 */
+            # sprintf('<%s>; rel=preload; as=image', static_url('src/images/icons.svg')),
+            # sprintf('<%s>; rel=preload; as=image', static_url('images/unicode-logo-framed.svg')),
+            sprintf('<%s>; rel=modulepreload; as=script', static_url('src/js/main.js')),
+        ], $additional);
+        header('Link:'.join(',', $headers), false);
+        header('Link: <https://stats.codepoints.net>; rel=preconnect', false);
+    }
+
+}
diff --git a/codepoints.net/lib/view_functions.php b/codepoints.net/lib/view_functions.php
index 8b04607f..8bfde995 100644
--- a/codepoints.net/lib/view_functions.php
+++ b/codepoints.net/lib/view_functions.php
@@ -96,7 +96,7 @@ function bl(Block $block, string $rel='', string $class='') : string {
  */
 function blimg(Block $block, int $width=16) : string {
     $name = str_replace([' ', '_', '-'], '', strtolower($block->name));
-    $url = sprintf('/static/images/LastResort.svg#%s', $name);
+    $url = sprintf('%s#%s', static_url('images/LastResort.svg'), $name);
     return sprintf('<svg width="%s" height="%s"><svg viewBox="194 97 1960 1960" width="100%%" height="100%%">'.
         '<use xlink:href="%s"/></svg></svg>', $width, $width, $url);
 }