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Merge pull request #59 from chokkyvista/alexa_timeout
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Reprompt to keep session alive for long downloads
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@dmhacker
dmhacker authored Feb 9, 2019
2 parents 8db5c91 + 04521c2 commit 60d09bb
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Showing 4 changed files with 245 additions and 114 deletions.
187 changes: 155 additions & 32 deletions src/index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -12,21 +12,29 @@ var response_messages = require("./util/responses.js");
// Create Alexa skill application
var app = new alexa.app("youtube");

// Set Heroku URL
var heroku = process.env.HEROKU_APP_URL || "https://dmhacker-youtube.herokuapp.com";
// Process environment variables
const heroku = process.env.HEROKU_APP_URL || "https://dmhacker-youtube.herokuapp.com";
const interactive_wait = !(process.env.DISABLE_INTERACTIVE_WAIT === "true" ||
process.env.DISABLE_INTERACTIVE_WAIT === true ||
process.env.DISABLE_INTERACTIVE_WAIT === 1);
const cache_polling_interval = parseInt(process.env.CACHE_POLLING_INTERVAL || "5000", 10);
const ask_interval = parseInt(process.env.ASK_INTERVAL || "45000", 10);

// Variables relating to videos waiting for user input
var buffer_search = {};
// Variables relating to videos waiting for user input
var buffer_search = {};

// Variables relating to the last video searched
var last_search = {};
var last_token = {};
var last_playback = {};

// Variables for repetition of current song
// Variables for repetition of current song
var repeat_infinitely = {};
var repeat_once = {};

// To track whether downloading is already in progress
var downloading = false;

/**
* Generates a random UUID. Used for creating an audio stream token.
*
Expand Down Expand Up @@ -103,7 +111,7 @@ function search_video(req, res, lang) {
return new Promise((resolve, reject) => {
var search = heroku + "/alexa/v3/search/" + new Buffer(query).toString("base64");

// Populate URL with correct language
// Populate URL with correct language
if (lang === "de-DE") {
search += "?language=de";
} else if (lang === "fr-FR") {
Expand All @@ -120,7 +128,7 @@ function search_video(req, res, lang) {
} else {
// Convert body text in response to JSON object
var body_json = JSON.parse(body);
if (body_json.status === "error" && body_json.message === "No results found") {
if (body_json.state === "error" && body_json.message === "No results found") {
// Query did not return any video
resolve({
message: response_messages[lang]["NO_RESULTS_FOUND"].formatUnicorn(query),
Expand Down Expand Up @@ -155,6 +163,7 @@ function search_video(req, res, lang) {

// Set most recently searched for video
buffer_search[userId] = metadata;
downloading = false;

res.reprompt().shouldEndSession(false);
}
Expand All @@ -167,8 +176,110 @@ function search_video(req, res, lang) {
});
}

function make_download_video_request(id) {
return new Promise((resolve, reject) => {
request(heroku + "/alexa/v3/download/" + id, function(err, res, body) {
if (err) {
console.error(err.message);
reject(err.message);
} else {
var body_json = JSON.parse(body);
var url = heroku + body_json.link;
console.log("Requested download for ... " + url);
resolve(url);
}
});
});
}

function check_cache_ready(id, timeout) {
return new Promise((resolve, reject) => {
request(heroku + "/alexa/v3/cache/" + id, function(err, res, body) {
if (!err) {
var body_json = JSON.parse(body);
if (body_json.hasOwnProperty('downloaded') && body_json['downloaded'] != null) {
if (body_json.downloaded) {
downloading = false;

console.log(id + " has been cached. Ready to play!");

resolve();
}
else {
downloading = true;

console.log(id + " is being cached.");
if (timeout <= 0) {
resolve();
return;
}

var interval = Math.min(cache_polling_interval, timeout);
console.log("Checking again in " + interval + "ms (delay: " + timeout + "ms).");

resolve(new Promise((_resolve, _reject) => {
setTimeout(() => {
_resolve(check_cache_ready(id, timeout - cache_polling_interval).catch(_reject));
}, interval);
}).catch(reject));
}
}
else {
console.log(id + " will not be cached.");
reject("Video unavailable.");
}
}
else {
console.error(err.message);
reject(err.message);
}
});
});
}

function respond_play(req, res) {
var userId = req.userId;

// Final response to the user, indicating that their video will be playing
var speech = new ssml();
var title = buffer_search[userId].title;
var message = response_messages[req.data.request.locale]["NOW_PLAYING"].formatUnicorn(title);
speech.say(message);
res.say(speech.ssml(true));

console.log("Starting to play ... " + title);

// Start playing the video!
restart_video(req, res, 0);
}

function interactively_wait_for_video(req, res) {
var userId = req.userId;
var id = buffer_search[userId].id;
return check_cache_ready(id, ask_interval).then(() => {
if (!downloading) {
// Download finished ... notify user
respond_play(req, res);
}
else {
console.log("Asking whether to continue waiting." );

// Download still in progress ... ask if the user wants to keep tracking
var message = response_messages[req.data.request.locale]["ASK_TO_CONTINUE"];
var speech = new ssml();
speech.say(message);
res.say(speech.ssml(true));
res.reprompt(message).shouldEndSession(false);
}
return res.send();
}).catch(reason => {
console.error(reason);
return res.fail(reason);
});
}

/**
* Downloads the mostly recent video the user requested.
* Downloads the mostly recent video the user requested.
*
* @param {Object} req A request from an Alexa device
* @param {Object} res A response that will be sent to the device
Expand All @@ -181,7 +292,7 @@ function download_video(req, res) {
console.log("Requesting download ... " + id);

return new Promise((resolve, reject) => {
var download = heroku + "/alexa/v3/download/" + id;
var download = heroku + "/alexa/v3/download/" + id;

// Make download request to server
request(download, function(err, res, body) {
Expand Down Expand Up @@ -209,12 +320,7 @@ function download_video(req, res) {
});
}).then(function() {
// Have Alexa tell the user that the video is finished downloading
var speech = new ssml();
speech.say(response_messages[req.data.request.locale]["NOW_PLAYING"].formatUnicorn(buffer_search[userId].title));
res.say(speech.ssml(true));

// Start playing the video!
restart_video(req, res, 0);
respond_play(req, res);

// Send response to Alexa device
res.send();
Expand All @@ -231,19 +337,17 @@ function download_video(req, res) {
* @param {Function} callback The function to execute about load completion
*/
function wait_for_video(id, callback) {
setTimeout(function() {
request(heroku + "/alexa/v3/cache/" + id, function(err, res, body) {
if (!err) {
var body_json = JSON.parse(body);
if (body_json.downloaded) {
callback();
}
else {
wait_for_video(id, callback);
}
request(heroku + "/alexa/v3/cache/" + id, function(err, res, body) {
if (!err) {
var body_json = JSON.parse(body);
if (body_json.downloaded) {
callback();
}
});
}, 2000);
else {
setTimeout(wait_for_video, cache_polling_interval, id, callback);
}
}
});
}

// Filter out bad requests (the client's ID is not the same as the server's)
Expand All @@ -260,6 +364,10 @@ app.pre = function(req, res, type) {
}
};

app.error = function(exc, req, res) {
res.say("An error occured: " + exc);
};

// Looking up a video in English
app.intent("GetVideoIntent", {
"slots": {
Expand Down Expand Up @@ -339,9 +447,24 @@ app.intent("AMAZON.YesIntent", function(req, res) {
if (!buffer_search.hasOwnProperty(userId) || buffer_search[userId] == null) {
res.send();
}
else {
else if (!interactive_wait) {
return download_video(req, res);
}
else {
var id = buffer_search[userId].id;
if (!downloading) {
return make_download_video_request(id)
.then(url => {
downloading = true;
last_search[userId] = url;
return interactively_wait_for_video(req, res);
})
.catch(reason => {
return res.fail(reason);
});
}
return interactively_wait_for_video(req, res);
}
});

app.intent("AMAZON.NoIntent", function(req, res) {
Expand All @@ -362,9 +485,9 @@ app.audioPlayer("PlaybackNearlyFinished", function(req, res) {
var userId = req.userId;

// Repeat is enabled, so begin next playback
if (has_video(userId) &&
((repeat_infinitely.hasOwnProperty(userId) && repeat_infinitely[userId]) ||
(repeat_once.hasOwnProperty(userId) && repeat_once[userId])))
if (has_video(userId) &&
((repeat_infinitely.hasOwnProperty(userId) && repeat_infinitely[userId]) ||
(repeat_once.hasOwnProperty(userId) && repeat_once[userId])))
{
// Generate new token for the stream
var new_token = uuidv4();
Expand Down Expand Up @@ -473,7 +596,7 @@ app.intent("AMAZON.PauseIntent", {}, function(req, res) {
res.send();
});

// User told Alexa to repeat audio once
// User told Alexa to repeat audio once
app.intent("AMAZON.RepeatIntent", {}, function(req, res) {
var userId = req.userId;

Expand Down
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