add upcloud key extractor

Co-authored-by: William Oldham <github@binaryoverload.co.uk>

src/providers/embeds/upcloud.ts

@@ -24,6 +24,34 @@ function isJSON(json: string) {
   }
 }
 
+/*
+example script segment:
+switch(I9){case 0x0:II=X,IM=t;break;case 0x1:II=b,IM=D;break;case 0x2:II=x,IM=f;break;case 0x3:II=S,IM=j;break;case 0x4:II=U,IM=G;break;case 0x5:II=partKeyStartPosition_5,IM=partKeyLength_5;}
+*/
+function extractKey(script: string): [number, number][] | null {
+  const startOfSwitch = script.lastIndexOf('switch');
+  const endOfCases = script.indexOf('partKeyStartPosition');
+  const switchBody = script.slice(startOfSwitch, endOfCases);
+
+  const nums: [number, number][] = [];
+  const matches = switchBody.matchAll(/:[a-zA-Z]+=([a-zA-Z]+),[a-zA-Z]+=([a-zA-Z]+);/g);
+  for (const match of matches) {
+    const innerNumbers: number[] = [];
+    for (const varMatch of [match[1], match[2]]) {
+      const regex = new RegExp(`${varMatch}=0x([a-zA-Z0-9]+)`, 'g');
+      const varMatches = [...script.matchAll(regex)];
+      const lastMatch = varMatches[varMatches.length - 1];
+      if (!lastMatch) return null;
+      const number = parseInt(lastMatch[1], 16);
+      innerNumbers.push(number);
+    }
+
+    nums.push([innerNumbers[0], innerNumbers[1]]);
+  }
+
+  return nums;
+}
+
 export const upcloudScraper = makeEmbed({
   id: 'upcloud',
   name: 'UpCloud',
@@ -45,20 +73,22 @@ export const upcloudScraper = makeEmbed({
     let sources: { file: string; type: string } | null = null;
 
     if (!isJSON(streamRes.sources)) {
-      const decryptionKey = JSON.parse(
-        await ctx.proxiedFetcher<string>(`https://raw.githubusercontent.com/enimax-anime/key/e4/key.txt`),
-      ) as [number, number][];
+      const scriptJs = await ctx.proxiedFetcher<string>(`https://rabbitstream.net/js/player/prod/e4-player.min.js`);
+      const decryptionKey = extractKey(scriptJs);
+      if (!decryptionKey) throw new Error('Key extraction failed');
 
       let extractedKey = '';
-      const sourcesArray = streamRes.sources.split('');
-      for (const index of decryptionKey) {
-        for (let i: number = index[0]; i < index[1]; i += 1) {
-          extractedKey += streamRes.sources[i];
-          sourcesArray[i] = '';
-        }
-      }
+      let strippedSources = streamRes.sources;
+      let totalledOffset = 0;
+      decryptionKey.forEach(([a, b]) => {
+        const start = a + totalledOffset;
+        const end = start + b;
+        extractedKey += streamRes.sources.slice(start, end);
+        strippedSources = strippedSources.replace(streamRes.sources.substring(start, end), '');
+        totalledOffset += b;
+      });
 
-      const decryptedStream = AES.decrypt(sourcesArray.join(''), extractedKey).toString(enc.Utf8);
+      const decryptedStream = AES.decrypt(strippedSources, extractedKey).toString(enc.Utf8);
       const parsedStream = JSON.parse(decryptedStream)[0];
       if (!parsedStream) throw new Error('No stream found');
       sources = parsedStream;