Work on fetching/converting google drive subtitles

.gitignore

@@ -10,3 +10,4 @@ node_modules
 *.key
 torlist
 www/cache
+google-drive-subtitles

lib/google2vtt.js

@@ -0,0 +1,139 @@
+var cheerio = require('cheerio');
+var https = require('https');
+var fs = require('fs');
+var path = require('path');
+var querystring = require('querystring');
+var crypto = require('crypto');
+
+var Logger = require('./logger');
+
+function md5(input) {
+    var hash = crypto.createHash('md5');
+    hash.update(input);
+    return hash.digest('base64').replace(/\//g, ' ')
+        .replace(/\+/g, '#')
+        .replace(/=/g, '-');
+}
+
+var slice = Array.prototype.slice;
+var subtitleDir = path.resolve(__dirname, '..', 'google-drive-subtitles');
+
+function padZeros(n) {
+    n = n.toString();
+    if (n.length < 2) n = '0' + n;
+    return n;
+}
+
+function formatTime(time) {
+    var hours = Math.floor(time / 3600);
+    time = time % 3600;
+    var minutes = Math.floor(time / 60);
+    time = time % 60;
+    var seconds = Math.floor(time);
+    var ms = time - seconds;
+
+    var list = [minutes, seconds];
+    if (hours) {
+        list.unshift(hours);
+    }
+
+    return list.map(padZeros).join(':') + ms.toFixed(3).substring(1);
+}
+
+function unescapeHtmlEntities(text) {
+    return text.replace(/&amp;/g, '&')
+        .replace(/&lt;/g, '<')
+        .replace(/&gt;/g, '>')
+        .replace(/&quot;/g, '"')
+        .replace(/&#39;/g, "'");
+}
+
+exports.convert = function convertSubtitles(subtitles) {
+    var $ = cheerio.load(subtitles, { xmlMode: true });
+    var lines = slice.call($('transcript text').map(function (index, elem) {
+        var start = parseFloat(elem.attribs.start);
+        var end = start + parseFloat(elem.attribs.dur);
+        var text = elem.children[0].data;
+
+        var line = formatTime(start) + ' --> ' + formatTime(end);
+        line += '\n' + unescapeHtmlEntities(text) + '\n';
+        return line;
+    }));
+
+    return 'WEBVTT\n\n' + lines.join('\n');
+};
+
+exports.attach = function setupRoutes(app) {
+    app.get('/gdvtt/:id/:lang/:name.vtt', handleGetSubtitles);
+};
+
+function handleGetSubtitles(req, res) {
+    var id = req.params.id;
+    var lang = req.params.lang;
+    var name = req.params.name;
+    var vid = req.query.vid;
+    if (typeof vid !== 'string' || typeof id !== 'string' || typeof lang !== 'string' ||
+            typeof name !== 'string') {
+        return res.sendStatus(400);
+    }
+    var file = [id, lang, md5(name)].join('_') + '.vtt';
+    var fileAbsolute = path.join(subtitleDir, file);
+
+    fs.exists(fileAbsolute, function (exists) {
+        if (exists) {
+            res.sendFile(file, { root: subtitleDir });
+        } else {
+            fetchSubtitles(id, lang, name, vid, fileAbsolute, function (err) {
+                if (err) {
+                    Logger.errlog.log(err.stack);
+                    return res.sendStatus(500);
+                }
+
+                res.sendFile(file, { root: subtitleDir });
+            });
+        }
+    });
+}
+
+function fetchSubtitles(id, lang, name, vid, file, cb) {
+    var query = {
+        id: id,
+        v: id,
+        vid: vid,
+        lang: lang,
+        name: name,
+        type: 'track',
+        kind: undefined
+    };
+
+    var url = 'https://drive.google.com/timedtext?' + querystring.stringify(query);
+    https.get(url, function (res) {
+        if (res.statusCode !== 200) {
+            return cb(new Error(res.statusMessage));
+        }
+
+        var buf = '';
+        res.setEncoding('utf-8');
+        res.on('data', function (data) {
+            buf += data;
+        });
+
+        res.on('end', function () {
+            try {
+                buf = exports.convert(buf);
+            } catch (e) {
+                return cb(e);
+            }
+
+            fs.writeFile(file, buf, function (err) {
+                if (err) {
+                    cb(err);
+                } else {
+                    cb();
+                }
+            });
+        });
+    }).on('error', function (err) {
+        cb(err);
+    });
+}

lib/server.js

@@ -14,6 +14,11 @@ module.exports = {
         fs.exists(chandumppath, function (exists) {
             exists || fs.mkdir(chandumppath);
         });
+
+        var gdvttpath = path.join(__dirname, "../google-drive-subtitles");
+        fs.exists(gdvttpath, function (exists) {
+            exists || fs.mkdir(gdvttpath);
+        });
         singleton = new Server();
         return singleton;
     },

lib/web/webserver.js

@@ -243,6 +243,7 @@ module.exports = {
         require("./auth").init(app);
         require("./account").init(app);
         require("./acp").init(app);
+        require("../google2vtt").attach(app);
         app.use(static(path.join(__dirname, "..", "..", "www"), {
             maxAge: Config.get("http.max-age") || Config.get("http.cache-ttl")
         }));