Add download video and save playlist support.

PlaylistSaverHelper/background.js

@@ -1,34 +1,127 @@
+function bytesToBase64Url(bytes) {
+    let binary = "";
+    for (let offset = 0; offset < bytes.length; offset += 8192) {
+        binary += String.fromCharCode(...bytes.subarray(offset, offset + 8192));
+    }
+    return btoa(binary).replaceAll("+", "-").replaceAll("/", "_").replace(/=+$/, "");
+}
+
+function base64UrlToBytes(value) {
+    const padded = value.replaceAll("-", "+").replaceAll("_", "/")
+        + "=".repeat((4 - value.length % 4) % 4);
+    return Uint8Array.from(atob(padded), character => character.charCodeAt(0));
+}
+
+async function hmacSha256(keyBytes, data) {
+    const key = await crypto.subtle.importKey(
+        "raw", keyBytes, { name: "HMAC", hash: "SHA-256" }, false, ["sign"]
+    );
+    return new Uint8Array(await crypto.subtle.sign("HMAC", key, data));
+}
+
+function joinBytes(...arrays) {
+    const result = new Uint8Array(arrays.reduce((size, array) => size + array.length, 0));
+    let offset = 0;
+    for (const array of arrays) {
+        result.set(array, offset);
+        offset += array.length;
+    }
+    return result;
+}
+
+async function encryptCookies(plaintext, secretKey) {
+    const masterKey = base64UrlToBytes(secretKey);
+    if (masterKey.length !== 32) {
+        throw new Error("The Helper secret key is invalid.");
+    }
+
+    const encoder = new TextEncoder();
+    const encryptionKey = await hmacSha256(masterKey, encoder.encode("PlaylistSaver cookie encryption"));
+    const authenticationKey = await hmacSha256(masterKey, encoder.encode("PlaylistSaver cookie authentication"));
+    const nonce = crypto.getRandomValues(new Uint8Array(16));
+    const plaintextBytes = encoder.encode(plaintext);
+    const ciphertext = new Uint8Array(plaintextBytes.length);
+
+    for (let offset = 0; offset < plaintextBytes.length; offset += 32) {
+        const counter = new Uint8Array(4);
+        new DataView(counter.buffer).setUint32(0, offset / 32, false);
+        const stream = await hmacSha256(encryptionKey, joinBytes(nonce, counter));
+        const blockLength = Math.min(32, plaintextBytes.length - offset);
+        for (let index = 0; index < blockLength; index++) {
+            ciphertext[offset + index] = plaintextBytes[offset + index] ^ stream[index];
+        }
+    }
+
+    const signedData = joinBytes(Uint8Array.of(1), nonce, ciphertext);
+    const tag = await hmacSha256(authenticationKey, signedData);
+    return bytesToBase64Url(joinBytes(signedData, tag));
+}
+
+async function launchPlaylistSaver() {
+    const { secretKey } = await chrome.storage.local.get("secretKey");
+    if (!secretKey) {
+        await chrome.storage.local.set({ showMissingKeyAlert: true });
+        await chrome.runtime.openOptionsPage();
+        return;
+    }
+
+    const cookies = await chrome.cookies.getAll({ domain: ".youtube.com" });
+    let output = "# Netscape HTTP Cookie File\n";
+    for (const cookie of cookies) {
+        const rawDomain = cookie.domain;
+        const domain = cookie.httpOnly ? `#HttpOnly_${rawDomain}` : rawDomain;
+        output += [
+            domain,
+            rawDomain.startsWith(".") ? "TRUE" : "FALSE",
+            cookie.path,
+            cookie.secure ? "TRUE" : "FALSE",
+            cookie.expirationDate ? Math.floor(cookie.expirationDate) : 0,
+            cookie.name,
+            cookie.value
+        ].join("\t") + "\n";
+    }
+
+    const encrypted = await encryptCookies(output, secretKey.trim());
+    const tabs = await chrome.tabs.query({ active: true, currentWindow: true });
+    if (!tabs[0]?.id) {
+        throw new Error("No active tab is available to launch PlaylistSaver.");
+    }
+    await chrome.tabs.update(tabs[0].id, {
+        url: `playlistsaver://open?encryptedcookies=${encrypted}`
+    });
+}
+
+async function openHelperSettings() {
+    await chrome.runtime.openOptionsPage();
+}
+
 chrome.commands.onCommand.addListener((command) => {
     if (command === "openPLKey") {
-
-        chrome.cookies.getAll({ domain: ".youtube.com" }, (cookies) => {
-            let output = "# Netscape HTTP Cookie File\n";
-
-            cookies.forEach(c => {
-                const domain = c.domain;
-                const flag = domain.startsWith('.') ? "TRUE" : "FALSE";
-                const path = c.path;
-                const secure = c.secure ? "TRUE" : "FALSE";
-                const expiration = c.expirationDate ? Math.floor(c.expirationDate) : 0;
-
-                output += [
-                    domain,
-                    flag,
-                    path,
-                    secure,
-                    expiration,
-                    c.name,
-                    c.value
-                ].join("\t") + "\n";
-            });
-
-            const encoded = btoa(output);
-
-            chrome.tabs.query({ active: true, currentWindow: true }, (tabs) => {
-                chrome.tabs.update(tabs[0].id, {
-                    url: `PlaylistSaver://open?base64cookies=${encoded}`
-                });
-            });
-        });
+        launchPlaylistSaver().catch(error => console.error("Unable to launch PlaylistSaver:", error));
+    } else if (command === "openPLSettingPageKey") {
+        openHelperSettings().catch(error => console.error("Unable to open Helper settings:", error));
     }
-});
+});
+
+chrome.runtime.onInstalled.addListener(() => {
+    chrome.contextMenus.removeAll(() => {
+        chrome.contextMenus.create({
+            id: "openPlaylistSaver",
+            title: "Open PlaylistSaver",
+            contexts: ["page"]
+        });
+        chrome.contextMenus.create({
+            id: "openHelperSettings",
+            title: "PlaylistSaver Helper Settings",
+            contexts: ["page"]
+        });
+    });
+});
+
+chrome.contextMenus.onClicked.addListener((info) => {
+    if (info.menuItemId === "openPlaylistSaver") {
+        launchPlaylistSaver().catch(error => console.error("Unable to launch PlaylistSaver:", error));
+    } else if (info.menuItemId === "openHelperSettings") {
+        openHelperSettings().catch(error => console.error("Unable to open Helper settings:", error));
+    }
+});