var Client = require('castv2-client').Client;
var DefaultMediaReceiver = require('castv2-client').DefaultMediaReceiver;
const googleTTS = require('google-tts-api');

var App = {
    playin: false,
    DeviceIp: "",
    Player: null,
    GoogleHome: function (host, url) {
        var client = new Client();
        client.connect(host, function () {
            client.launch(DefaultMediaReceiver, function (err, player) {
                client.setVolume({ level: 1 }, function(err, volume) {
                  if (err) {
                    console.log('Error on setVolume:', err);
                  } else {
                    console.log('Volume set to ' + volume)
                  }

                });
                var media = {
                    contentId: url,
                    contentType: 'audio/mp3',
                    streamType: 'BUFFERED'
                };
                App.Player = player;
                App.Player.load(media, { autoplay: true }, function (err, status) {
                    App.Player.on('status', function (status) {
                        if (status.playerState === "IDLE" && App.playin === false) {
                            client.close();
                        }
                    });
                });
            });
        });
        client.on('error', function (err) {
            console.log('Error: %s', err.message);
            client.close();
        });
    },
    run: function (ip, text) {
        App.DeviceIp = ip;
        const url = googleTTS.getAudioUrl(text, {
            lang: 'en-US',
            slow: false,
            host: 'https://translate.google.com',
        });
        App.GoogleHome(App.DeviceIp, url, function (res) {
            console.log(res);
        })
    },
    broadcast: function(text){
        //From config, 192.168.68.105,192.168.68.107,192.168.68.124
        const ips = process.env.GOOGLEHOME_IPS.split(","); 
        for (var s of ips){
            App.run(s, text);
        }
    }
};
App.run("192.168.68.124", "Test message sent to one device");
//Only works if you did step 4.5
//App.broadcast("Broadcasted to all of the devices"); 

client.setVolume({ level: 1 }, function(err, volume) {
  if (err) {
    // Handle error as appropriate
    console.log('Error on setVolume:', err);
  } else {
    console.log('Volume:', volume)
  }
  
});

var Client = require('castv2-client').Client;
var DefaultMediaReceiver = require('castv2-client').DefaultMediaReceiver;
const googleTTS = require('google-tts-api');

• castv2-client
  • A Chromecast client based on the new (CASTV2) protocol. This is how we communicate to our Google Home/Google Home Mini.
• google-tts-api
  • An API from google that converts our plaintext string into a mp3 file that gets played on our Google Home/Google Home Mini
• Client
  • This is our object that allows us to control our Google Home, it references the speaker itself and allows us to alter it like change the volume on it.
• DefaultMediaReceiver
  • This is the default client provided by the Google API. Handles basic audio streaming. You can read more about the DefaultMediaReciever and how to create your own at the above link

var App = {    
    playin: false,
    DeviceIp: "",
    Player: null,
    GoogleHome: function (host, url) {
        var client = new Client();
        client.connect(host, function () {
            client.launch(DefaultMediaReceiver, function (err, player) {
                client.setVolume({ level: 1 });
                var media = {
                    contentId: url,
                    contentType: 'audio/mp3',
                    streamType: 'BUFFERED'
                };
                App.Player = player;
                App.Player.load(media, { autoplay: true }, function (err, status) {
                    App.Player.on('status', function (status) {
                        if (status.playerState === "IDLE" && App.playin === false) {
                            client.close();
                        }
                    });
                });
            });
        });
        client.on('error', function (err) {
            console.log('Error: %s', err.message);
            client.close();
        });
    },

This is our initial skeleton for our App object. The main section to look at is the GoogleHome function, which takes a "host" parameter (our google home static IP) and a "url" parameter which is our Google TTS service.

We then connect to the client and launch the "DefaultMediaReciever" which will notify the GoogleHome that we are going to be sending some media to be played.

We set the volume to the highest level, goes from 0F - 1F (think percentages so .6 would be 60% volume).

After that we construct our media object, this lets the google home know that it is going to be an audio/mp3 file that is coming from an URL (the google tts url)

We then load it nto the player (set auto play to true so it broadcasts as soon as it loads) and when the status of the player goes to "IDLE" it means the media is done playing so we can then close it.

I just dumped any errors that occured to console, but if you have any other error handling logic add it there.

run: function (ip, text) {
        App.DeviceIp = ip;
        const url = googleTTS.getAudioUrl(text, {
            lang: 'en-US',
            slow: false,
            host: 'https://translate.google.com',
        });
        App.GoogleHome(App.DeviceIp, url, function (res) {
            console.log(res);
        })
    },

This next section is our entry point to each individual google home mini. The "ip" parameter is the numerical IP for our GoogleHome and the "text" parameter is the text you want to get broadcasted.

The googleTTS.getAudioUrl() is a wrapper around Google's TTS service, you can always construct the link yourself but I find it easier to just use a library which abstracts a lot of it out. The value of "url" after the library will be something like
https://translate.google.com/translate_tts?ie=UTF-8&q=Hello+this+is+a+test+message+to+see+if+TTS+works&tl=en&total=1&idx=0&textlen=48&client=tw-ob&prev=input&ttspeed=1

We then call our GoogleHome function defined in the above section with our parameters and it should call it and run.

broadcast: function(text){
    	//From config, 192.168.68.105,192.168.68.107,192.168.68.124
        const ips = process.env.GOOGLEHOME_IPS.split(","); 
        for (var s of ips){
            App.run(s, text);
        }
    }
};

This last section is how we broadcast it to multiple devices at once. A simple for loop that iterates over each IP of each of the Google Home Mini and then broadcasts it to them

App.run("192.168.68.124", "Test message sent to one device");

This is the entry point to the application, you can abstract the two parameters to console or some other variable that you have defined to change the target and parameters.