probe videos in background

frontend/js/player.js

@@ -75,6 +75,19 @@ App.player = App.player || {};
             return;
         }
 
+        // Expand the candidate sources into an ordered playback plan. When a
+        // source has been proven (in the background) to play directly, try the
+        // raw upstream URL first and keep the proxy as the immediate fallback;
+        // unproven sources go straight through the proxy.
+        const directProven = (url) => !!(App.videos && App.videos.isDirectProven && App.videos.isDirectProven(url));
+        const playbackPlan = [];
+        sources.forEach((resolved) => {
+            if (directProven(resolved.url)) {
+                playbackPlan.push({ resolved, direct: true });
+            }
+            playbackPlan.push({ resolved, direct: false });
+        });
+
         if (useMobileFullscreen) {
             const host = getMobileVideoHost();
             if (video.parentElement !== host) {
@@ -120,8 +133,9 @@ App.player = App.player || {};
         // Attempts to play a single source. On a fatal failure it advances to
         // the next candidate, or reports an error once the list is exhausted.
         const attempt = async (index) => {
-            const resolved = sources[index];
-            const hasNext = index + 1 < sources.length;
+            const entry = playbackPlan[index];
+            const resolved = entry.resolved;
+            const hasNext = index + 1 < playbackPlan.length;
             let playbackStarted = false;
             let settled = false;
 
@@ -137,10 +151,17 @@ App.player = App.player || {};
                 }
             };
 
-            const refererParam = resolved.referer ? `&referer=${encodeURIComponent(resolved.referer)}` : '';
-            const userAgentParam = resolved.userAgent ? `&User-Agent=${encodeURIComponent(resolved.userAgent)}` : '';
-            const liveParam = resolved.isLive ? '&live=1' : '';
-            const streamUrl = `/api/stream?url=${encodeURIComponent(resolved.url)}${refererParam}${userAgentParam}${liveParam}`;
+            // Proven-direct entries hit the upstream URL straight from the
+            // browser; everything else is wrapped in the backend stream proxy.
+            let streamUrl;
+            if (entry.direct) {
+                streamUrl = resolved.url;
+            } else {
+                const refererParam = resolved.referer ? `&referer=${encodeURIComponent(resolved.referer)}` : '';
+                const userAgentParam = resolved.userAgent ? `&User-Agent=${encodeURIComponent(resolved.userAgent)}` : '';
+                const liveParam = resolved.isLive ? '&live=1' : '';
+                streamUrl = `/api/stream?url=${encodeURIComponent(resolved.url)}${refererParam}${userAgentParam}${liveParam}`;
+            }
             let isHls = /\.m3u8($|\?)/i.test(resolved.url);
             let isDirectMedia = /\.(mp4|m4v|m4s|webm|ts|mov)($|\?)/i.test(resolved.url);
             // Live cam streams resolve (server-side) to HLS; treat them as HLS up
@@ -165,7 +186,7 @@ App.player = App.player || {};
             video.removeAttribute('src');
             video.load();
 
-            if (!isHls) {
+            if (!isHls && !entry.direct) {
                 try {
                     const headResp = await fetch(streamUrl, { method: 'HEAD' });
                     const contentType = headResp.headers.get('Content-Type') || '';

frontend/js/videos.js

@@ -290,6 +290,9 @@ App.videos = App.videos || {};
         items.forEach(v => {
             if (state.renderedVideoIds.has(v.id)) return;
             state.loadedVideos.push(v);
+            // Probe in the background whether this video's best source plays
+            // directly, so playback can bypass the proxy when proven.
+            App.videos.probeVideoSources(v);
 
             const card = document.createElement('div');
             card.className = 'video-card';
@@ -685,6 +688,81 @@ App.videos = App.videos || {};
         return sources.length ? sources[0] : { url: '', referer: '', userAgent: '', isLive: false };
     };
 
+    // Background "direct playability" probe. The backend proxy exists to work
+    // around CORS, hotlink (403) protection, and TLS fingerprinting. When the
+    // browser can fetch a media URL cross-origin and actually read the response
+    // (CORS allowed, not blocked/403), playing it directly works and the proxy
+    // is pure overhead. We probe each loaded video's best source in the
+    // background and, only when proven, let the player skip the proxy.
+    const DIRECT_PROBE_TIMEOUT_MS = 8000;
+    // Only URLs that the player can hand straight to <video>/hls.js are worth
+    // probing; anything else (e.g. a live channel page URL) is resolved
+    // server-side and must keep going through the proxy.
+    const DIRECT_PLAYABLE_RE = /\.(mp4|m4v|m4s|webm|ts|mov|m3u8)($|\?)/i;
+
+    // url -> true (proven directly playable) | false (proven not). Absent means
+    // unknown/unprobed, in which case the proxy is used.
+    App.videos._directStatus = new Map();
+    const directPending = new Map();
+
+    App.videos.isDirectProven = function(url) {
+        return App.videos._directStatus.get(url) === true;
+    };
+
+    App.videos.probeDirect = function(url) {
+        if (!url) return Promise.resolve(false);
+        if (App.videos._directStatus.has(url)) {
+            return Promise.resolve(App.videos._directStatus.get(url));
+        }
+        if (directPending.has(url)) {
+            return directPending.get(url);
+        }
+        const promise = (async () => {
+            const controller = new AbortController();
+            const timer = setTimeout(() => controller.abort(), DIRECT_PROBE_TIMEOUT_MS);
+            let ok = false;
+            try {
+                // A simple GET (no custom headers) avoids a CORS preflight. If
+                // the response is readable and successful, CORS + reachability
+                // are both proven; we abort immediately so the body isn't
+                // downloaded (it can be a whole video file).
+                const res = await fetch(url, {
+                    method: 'GET',
+                    mode: 'cors',
+                    credentials: 'omit',
+                    signal: controller.signal
+                });
+                ok = res.ok || res.status === 206;
+                controller.abort();
+            } catch (err) {
+                ok = false;
+            } finally {
+                clearTimeout(timer);
+            }
+            App.videos._directStatus.set(url, ok);
+            directPending.delete(url);
+            return ok;
+        })();
+        directPending.set(url, promise);
+        return promise;
+    };
+
+    // Kicks off a background probe of a video's best (first-played) source so a
+    // later playback can skip the proxy if the direct URL is proven reachable.
+    App.videos.probeVideoSources = function(video) {
+        if (!video || typeof video !== 'object') return;
+        let sources;
+        try {
+            sources = App.videos.resolveStreamSources(video);
+        } catch (err) {
+            return;
+        }
+        const best = sources && sources[0];
+        if (!best || !best.url || best.isLive) return;
+        if (!DIRECT_PLAYABLE_RE.test(best.url)) return;
+        App.videos.probeDirect(best.url);
+    };
+
     // Builds a proxied stream URL. Extra params other than `url` are forwarded
     // by the backend as request headers, so use real header names here.
     App.videos.buildStreamUrlFromSource = function(resolved) {