stream/internal: special youtube stream handling

src/modules/stream/internal.js

@@ -1,6 +1,76 @@
 import { request } from 'undici'
+import { Readable } from 'node:stream'
+import { assert } from 'console'
+import { getHeaders } from './shared.js'
+
+const CHUNK_SIZE = BigInt(8e6); // 8 MB
+const min = (a, b) => a < b ? a : b;
+
+async function* readChunks(streamInfo, size) {
+    let read = 0n;
+    while (read < size) {
+        if (streamInfo.controller.signal.aborted) {
+            throw new Error("controller aborted");
+        }
+
+        const chunk = await request(streamInfo.url, {
+            headers: {
+                ...getHeaders('youtube'),
+                Range: `bytes=${read}-${read + CHUNK_SIZE}`
+            },
+            signal: streamInfo.controller.signal
+        });
+
+        const expected = min(CHUNK_SIZE, size - read);
+        const received = BigInt(chunk.headers['content-length']);
+
+        if (received < expected / 2n) {
+            streamInfo.controller.abort();
+        }
+        
+        for await (const data of chunk.body) {
+            yield data;
+        }
+
+        read += received;
+    }
+} 
+
+function chunkedStream(streamInfo, size) {
+    assert(streamInfo.controller instanceof AbortController);
+    const stream = Readable.from(readChunks(streamInfo, size));
+    return stream;
+}
+
+async function handleYoutubeStream(streamInfo, res) {
+    try {
+        const req = await fetch(streamInfo.url, {
+            headers: getHeaders('youtube'),
+            method: 'HEAD',
+            signal: streamInfo.controller.signal
+        });
+
+        streamInfo.url = req.url;
+        const size = BigInt(req.headers.get('content-length'));
+
+        if (req.status !== 200 || !size)
+            return res.destroy();
+
+        const stream = chunkedStream(streamInfo, size);
+
+        res.setHeader('content-type', req.headers.get('content-type'));
+        stream.pipe(res);
+        stream.on('error', () => res.destroy());
+    } catch {
+        res.destroy();
+    }
+}
 
 export async function internalStream(streamInfo, res) {
+    if (streamInfo.service === 'youtube') {
+        return handleYoutubeStream(streamInfo, res);
+    }
+
     try {
         const req = await request(streamInfo.url, {
             headers: streamInfo.headers,