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Improve architecture
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@younesaassila
younesaassila committed Dec 22, 2023
1 parent 8c9de42 commit 714ec4a
Showing 1 changed file with 88 additions and 64 deletions.
152 changes: 88 additions & 64 deletions src/page/getFetch.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -8,7 +8,6 @@ import {
twitchGqlHostRegex,
usherHostRegex,
videoWeaverHostRegex,
videoWeaverUrlRegex,
} from "../common/ts/regexes";
import { State } from "../store/types";

Expand All @@ -21,6 +20,11 @@ export interface FetchOptions {
state?: State;
sendMessageToWorkers?: (message: any) => void;
}
export interface VideoWeaver {
assigned: Map<string, string>; // E.g. "720p60" -> "https://video-weaver.fra02.hls.ttvnw.net/v1/playlist/..."
replacement: Map<string, string> | null; // Same as above, but with new URLs.
consecutiveMidrollResponses: number; // Used to avoid infinite loops.
}
export interface PlaybackAccessToken {
value: string;
signature: string;
Expand All @@ -36,18 +40,12 @@ enum MessageType {
}

export function getFetch(options: FetchOptions): typeof fetch {
// TODO: Clear variables on navigation.
const knownVideoWeaverUrls = new Set<string>();
const videoWeaverUrlsToFlag = new Map<string, number>(); // Video Weaver URLs to flag -> number of times flagged.

// TODO: Again, what happens when the user navigates to another channel?
let cachedPlaybackTokenRequestHeaders: Map<string, string> | null = null;
let cachedPlaybackTokenRequestBody: string | null = null;
let cachedUsherRequestUrl: string | null = null;

let assignedVideoWeaversMap: Map<string, string> | null = null;
let replacementVideoWeaversMap: Map<string, string> | null = null;
let consecutiveMidrollResponses = 0;
// TODO: What happens when the user navigates to another channel?
let videoWeavers: VideoWeaver[] = [];
let proxiedVideoWeaverUrls = new Set<string>(); // Used to proxy only the first request to each Video Weaver URL.
let cachedPlaybackTokenRequestHeaders: Map<string, string> | null = null; // Cached by page script.
let cachedPlaybackTokenRequestBody: string | null = null; // Cached by page script.
let cachedUsherRequestUrl: string | null = null; // Cached by worker script.

if (options.shouldWaitForStore) {
setTimeout(() => {
Expand All @@ -73,7 +71,7 @@ export function getFetch(options: FetchOptions): typeof fetch {
});
}

async function setReplacementVideoWeaversMap() {
async function setVideoWeaverReplacementMap(videoWeaver: VideoWeaver) {
try {
console.log("[TTV LOL PRO] 🔄 Checking for new Video Weaver URLs…");
const newUsherManifest = await fetchReplacementUsherManifest(
Expand All @@ -83,14 +81,26 @@ export function getFetch(options: FetchOptions): typeof fetch {
console.log("[TTV LOL PRO] 🔄 No new Video Weaver URLs found.");
return;
}
replacementVideoWeaversMap =
getVideoWeaversMapFromUsherResponse(newUsherManifest);
videoWeaver.replacement =
getVideoWeaverMapFromUsherResponse(newUsherManifest);
console.log(
"[TTV LOL PRO] 🔄 Found new Video Weaver URLs:",
Object.fromEntries(replacementVideoWeaversMap?.entries() ?? [])
Object.fromEntries(videoWeaver.replacement?.entries() ?? [])
);
// Send replacement Video Weaver URLs to content script.
const videoWeaverUrls = [...(videoWeaver.replacement?.values() ?? [])];
if (cachedUsherRequestUrl != null && videoWeaverUrls.length > 0) {
// Send Video Weaver URLs to content script.
sendMessageToContentScript(options.scope, {
type: "UsherResponse",
channel: findChannelFromUsherUrl(cachedUsherRequestUrl),
videoWeaverUrls,
proxyCountry:
/USER-COUNTRY="([A-Z]+)"/i.exec(newUsherManifest)?.[1] || null,
});
}
} catch (error) {
replacementVideoWeaversMap = null;
videoWeaver.replacement = null;
console.error(
"[TTV LOL PRO] 🔄 Failed to get new Video Weaver URLs:",
error
Expand All @@ -100,7 +110,7 @@ export function getFetch(options: FetchOptions): typeof fetch {

// // TEST CODE
// if (options.scope === "worker") {
// setTimeout(setReplacementVideoWeaversMap, 30000);
// setTimeout(() => setVideoWeaverReplacementMap(videoWeavers[0]), 30000);
// }

return async function fetch(
Expand Down Expand Up @@ -135,7 +145,7 @@ export function getFetch(options: FetchOptions): typeof fetch {

// Twitch GraphQL requests.
if (host != null && twitchGqlHostRegex.test(host)) {
requestBody = await readRequestBody();
requestBody ??= await readRequestBody();
// Integrity requests.
if (url === "https://gql.twitch.tv/integrity") {
console.debug(
Expand Down Expand Up @@ -215,19 +225,28 @@ export function getFetch(options: FetchOptions): typeof fetch {

// Video Weaver requests.
if (host != null && videoWeaverHostRegex.test(host)) {
console.debug(`[TTV LOL PRO] 🥅 Caught Video Weaver request '${url}'.`);
const videoWeaver = videoWeavers.find(videoWeaver =>
[...(videoWeaver.assigned.values() ?? [])].includes(url)
);
if (videoWeaver == null) {
console.warn(
"[TTV LOL PRO] 🥅 Caught Video Weaver request, but no associated Video Weaver found."
);
}
let videoWeaverUrl = url;
if (replacementVideoWeaversMap != null) {
const video = [...(assignedVideoWeaversMap?.entries() ?? [])].find(
([key, value]) => value === url

if (videoWeaver?.replacement != null) {
const video = [...(videoWeaver.assigned.entries() ?? [])].find(
([, url]) => url === videoWeaverUrl
)?.[0];
if (video != null && replacementVideoWeaversMap.has(video)) {
videoWeaverUrl = replacementVideoWeaversMap.get(video)!;
// Replace Video Weaver URL with replacement URL.
if (video != null && videoWeaver.replacement.has(video)) {
videoWeaverUrl = videoWeaver.replacement.get(video)!;
console.log(
`[TTV LOL PRO] 🔄 Replaced Video Weaver URL '${url}' with '${videoWeaverUrl}'.`
);
} else if (replacementVideoWeaversMap.size > 0) {
videoWeaverUrl = [...replacementVideoWeaversMap.values()][0];
} else if (videoWeaver.replacement.size > 0) {
videoWeaverUrl = [...videoWeaver.replacement.values()][0];
console.log(
`[TTV LOL PRO] 🔄 Replaced Video Weaver URL '${url}' with '${videoWeaverUrl}' (fallback).`
);
Expand All @@ -238,36 +257,26 @@ export function getFetch(options: FetchOptions): typeof fetch {
}
}

const isNewUrl = !knownVideoWeaverUrls.has(videoWeaverUrl);
const isFlaggedUrl = videoWeaverUrlsToFlag.has(videoWeaverUrl);

if (isNewUrl || isFlaggedUrl) {
// Flag first request to each Video Weaver URL.
if (!proxiedVideoWeaverUrls.has(videoWeaverUrl)) {
proxiedVideoWeaverUrls.add(videoWeaverUrl);
console.log(
`[TTV LOL PRO] 🥅 Caught ${
isNewUrl
? "first request to Video Weaver URL"
: "Video Weaver request to flag"
}. Flagging…`
`[TTV LOL PRO] 🥅 Caught first request to Video Weaver URL. Flagging…`
);
flagRequest(headersMap);
// videoWeaverUrlsToFlag.set(
// videoWeaverUrl,
// (videoWeaverUrlsToFlag.get(videoWeaverUrl) ?? 0) + 1
// );
if (isNewUrl) knownVideoWeaverUrls.add(videoWeaverUrl);
}

response = await NATIVE_FETCH(videoWeaverUrl, {
...init,
headers: Object.fromEntries(headersMap),
});
} else {
response = await NATIVE_FETCH(input, {
response ??= await NATIVE_FETCH(videoWeaverUrl, {
...init,
headers: Object.fromEntries(headersMap),
});
}

response ??= await NATIVE_FETCH(input, {
...init,
headers: Object.fromEntries(headersMap),
});

//#endregion

// Reading the response body can be expensive, so we only do it if we need to.
Expand All @@ -282,14 +291,17 @@ export function getFetch(options: FetchOptions): typeof fetch {

// Usher responses.
if (host != null && usherHostRegex.test(host)) {
responseBody = await readResponseBody();
console.debug("[TTV LOL PRO] 🥅 Caught Usher response.");
assignedVideoWeaversMap =
getVideoWeaversMapFromUsherResponse(responseBody);
replacementVideoWeaversMap = null;
const videoWeaverUrls = responseBody
.split("\n")
.filter(line => videoWeaverUrlRegex.test(line));
responseBody ??= await readResponseBody();
console.log("[TTV LOL PRO] 🥅 Caught Usher response.");
const videoWeaverMap = getVideoWeaverMapFromUsherResponse(responseBody);
if (videoWeaverMap != null) {
videoWeavers.push({
assigned: videoWeaverMap,
replacement: null,
consecutiveMidrollResponses: 0,
});
}
const videoWeaverUrls = [...(videoWeaverMap?.values() ?? [])];
// Send Video Weaver URLs to content script.
sendMessageToContentScript(options.scope, {
type: "UsherResponse",
Expand All @@ -299,12 +311,21 @@ export function getFetch(options: FetchOptions): typeof fetch {
/USER-COUNTRY="([A-Z]+)"/i.exec(responseBody)?.[1] || null,
});
// Remove all Video Weaver URLs from known URLs.
videoWeaverUrls.forEach(url => knownVideoWeaverUrls.delete(url));
videoWeaverUrls.forEach(url => proxiedVideoWeaverUrls.delete(url));
}

// Video Weaver responses.
if (host != null && videoWeaverHostRegex.test(host)) {
responseBody = await readResponseBody();
responseBody ??= await readResponseBody();
const videoWeaver = videoWeavers.find(videoWeaver =>
[...(videoWeaver.assigned.values() ?? [])].includes(url)
);
if (videoWeaver == null) {
console.warn(
"[TTV LOL PRO] 🥅 Caught Video Weaver response, but no associated Video Weaver found."
);
return response;
}

// Check if response contains midroll ad.
if (
Expand All @@ -314,16 +335,18 @@ export function getFetch(options: FetchOptions): typeof fetch {
console.log(
"[TTV LOL PRO] 🥅 Caught Video Weaver response containing ad."
);
consecutiveMidrollResponses += 1;
videoWeaver.consecutiveMidrollResponses += 1;
// Avoid infinite loops.
if (consecutiveMidrollResponses <= 2) {
await setReplacementVideoWeaversMap();
if (videoWeaver.consecutiveMidrollResponses <= 2) {
await setVideoWeaverReplacementMap(videoWeaver);
cancelRequest();
} else {
replacementVideoWeaversMap = null;
videoWeaver.replacement = null;
}
} else {
// No ad, clear attempts.
consecutiveMidrollResponses = 0;
videoWeaver.consecutiveMidrollResponses = 0;
console.debug("[TTV LOL PRO] Caught Video Weaver response WITHOUT ad.");
}
}

Expand Down Expand Up @@ -489,6 +512,7 @@ async function fetchReplacementPlaybackAccessToken(
method: "POST",
headers: {
// TODO: Find unnecessary headers.
// TODO: Flag this request!!
Accept: "*/*",
"Accept-Language": "en-US",
"Accept-Encoding": "gzip, deflate, br",
Expand Down Expand Up @@ -572,7 +596,7 @@ async function fetchReplacementUsherManifest(
}
}

function getVideoWeaversMapFromUsherResponse(
function getVideoWeaverMapFromUsherResponse(
response: string
): Map<string, string> | null {
const parser = new m3u8Parser.Parser();
Expand Down

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