Add mid-download token refresh, fix headers length overflow bug (#93)

* Add mid-download token refresh and header size fix for Node v8

* Refactor puppeteer test

* Remove note on mid-download token refresh bug

* Add source maps to build step

* Fix npm build script

src/TokenCache.ts

@@ -56,16 +56,23 @@ export class TokenCache {
         });
     }
 
-    public async RefreshToken(session: Session): Promise<string | null> {
+    public async RefreshToken(session: Session, cookie?: string | null): Promise<string | null> {
         let endpoint = `${session.ApiGatewayUri}refreshtoken?api-version=${session.ApiGatewayVersion}`;
 
-        let response = await axios.get(endpoint,
-            {
-                headers: {
-                    Authorization: `Bearer ${session.AccessToken}`
-                }
-            });
+        let headers: Function = (): object => {
+            if (cookie) {
+                return {
+                    Cookie: cookie
+                };
+            }
+            else {
+                return {
+                    Authorization: 'Bearer ' + session.AccessToken
+                };
+            }
+        }
 
+        let response = await axios.get(endpoint, { headers: headers() });
         let freshCookie: string | null = null;
         
         try {

src/destreamer.ts

@@ -23,6 +23,10 @@ import cliProgress from 'cli-progress';
 const { FFmpegCommand, FFmpegInput, FFmpegOutput } = require('@tedconf/fessonia')();
 const tokenCache = new TokenCache();
 
+// The cookie lifetime is one hour,
+// let's refresh every 3000 seconds.
+const REFRESH_TOKEN_INTERVAL = 3000;
+
 async function init() {
     setProcessEvents(); // must be first!
 
@@ -127,6 +131,7 @@ function extractVideoGuid(videoUrls: string[]): string[] {
 
 async function downloadVideo(videoUrls: string[], outputDirectories: string[], session: Session) {
     const videoGuids = extractVideoGuid(videoUrls);
+    let lastTokenRefresh: number;
 
     console.log('Fetching metadata...');
 
@@ -147,7 +152,10 @@ async function downloadVideo(videoUrls: string[], outputDirectories: string[], s
     if (argv.verbose)
         console.log(outputDirectories);
 
+
+    let freshCookie: string | null = null;
     const outDirsIdxInc = outputDirectories.length > 1 ? 1:0;
+
     for (let i=0, j=0, l=metadata.length; i<l; ++i, j+=outDirsIdxInc) {
         const video = metadata[i];
         const pbar = new cliProgress.SingleBar({
@@ -178,13 +186,32 @@ async function downloadVideo(videoUrls: string[], outputDirectories: string[], s
 
         // Try to get a fresh cookie, else gracefully fall back
         // to our session access token (Bearer)
-        let freshCookie = await tokenCache.RefreshToken(session);
-        let headers = `Authorization:\ Bearer\ ${session.AccessToken}`;
+        freshCookie = await tokenCache.RefreshToken(session, freshCookie);
+
+        // Don't remove the "useless" escapes otherwise ffmpeg will
+        // not pick up the header
+        // eslint-disable-next-line no-useless-escape
+        let headers = 'Authorization:\ Bearer\ ' + session.AccessToken;
         if (freshCookie) {
-            console.info(colors.green('Using a fresh cookie.'));
-            headers = `Cookie:\ ${freshCookie}`;
+            lastTokenRefresh = Date.now();
+            if (argv.verbose) {
+                console.info(colors.green('Using a fresh cookie.'));
+            }
+            // eslint-disable-next-line no-useless-escape
+            headers = 'Cookie:\ ' + freshCookie;
         }
 
+        const RefreshTokenMaybe = async (): Promise<void> => {
+            let elapsed = Date.now() - lastTokenRefresh;
+            if (elapsed > REFRESH_TOKEN_INTERVAL * 1000) {
+                if (argv.verbose) {
+                    console.info(colors.green('\nRefreshing access token...'));
+                }
+                lastTokenRefresh = Date.now();
+                freshCookie = await tokenCache.RefreshToken(session, freshCookie);
+            }
+        };
+
         const outputPath = outputDirectories[j] + path.sep + video.title + '.mp4';
         const ffmpegInpt = new FFmpegInput(video.playbackUrl, new Map([
             ['headers', headers]
@@ -192,7 +219,7 @@ async function downloadVideo(videoUrls: string[], outputDirectories: string[], s
         const ffmpegOutput = new FFmpegOutput(outputPath);
         const ffmpegCmd = new FFmpegCommand();
         
-        const cleanupFn = function () {
+        const cleanupFn = (): void => {
             pbar.stop();
 
            if (argv.noCleanup)
@@ -211,9 +238,9 @@ async function downloadVideo(videoUrls: string[], outputDirectories: string[], s
         ffmpegCmd.addInput(ffmpegInpt);
         ffmpegCmd.addOutput(ffmpegOutput);
 
-        // set events
         ffmpegCmd.on('update', (data: any) => {
             const currentChunks = ffmpegTimemarkToChunk(data.out_time);
+            RefreshTokenMaybe();
 
             pbar.update(currentChunks, {
                 speed: data.bitrate