Google Text-To-Speech API

I want to know how can I use Google Text-to-Speech API in my .NET project. I think I need to call a URL to use the web service, but the idea for me is not clear. Can anyone help?

Old answer:

Try using this URL: http://translate.google.com/translate_tts?tl=en&q=Hello%20World It will automatically generate a wav file which you can easily get with an HTTP request through any .net programming.

Edit:

Ohh Google, you thought you could prevent people from using your wonderful service with flimsy http header verification.

Here is a solution to get a response in multiple languages (I'll try to add more as we go):

NodeJS

// npm install `request`
const fs = require('fs');
const request = require('request');
const text = 'Hello World';

const options = {
    url: `https://translate.google.com/translate_tts?ie=UTF-8&q=${encodeURIComponent(text)}&tl=en&client=tw-ob`,
    headers: {
        'Referer': 'http://translate.google.com/',
        'User-Agent': 'stagefright/1.2 (Linux;Android 5.0)'
    }
}

request(options)
    .pipe(fs.createWriteStream('tts.mp3'))

Curl

curl 'https://translate.google.com/translate_tts?ie=UTF-8&q=Hello%20Everyone&tl=en&client=tw-ob' -H 'Referer: http://translate.google.com/' -H 'User-Agent: stagefright/1.2 (Linux;Android 5.0)' > google_tts.mp3

Note that the headers are based on @Chris Cirefice's example, if they stop working at some point I'll attempt to recreate conditions for this code to function. All credits for the current headers go to him and the wonderful tool that is WireShark. (also thanks to Google for not patching this)

In an update to Schahriar SaffarShargh's answer, Google has recently implemented a 'Google abuse' feature, making it impossible to send just any regular old HTTP GET to a URL such as:

http://translate.google.com/translate_tts?tl=en&q=Hello%20World

which worked just fine and dandy previously. Now, following such a link presents you with a CAPTCHA. This also affects HTTP GET requests out-of-browser (such as with cURL), because using that URL gives a redirect to the abuse protection page (the CAPTCHA).

To start, you have to add the query parameter client to the request URL:

http://translate.google.com/translate_tts?tl=en&q=Hello%20World&client=t

Google Translate sends &client=t, so you should too.

Before you make that HTTP request, make sure that you set the Referer header:

Referer: http://translate.google.com/

Evidently, the User-Agent header is also required, but interestingly enough it can be blank:

User-Agent:

Edit: NOTE - on some user-agents, such as Android 4.X, the custom User-Agent header is not sent, meaning that Google will not service the request. In order to solve that problem, I simply set the User-Agent to a valid one, such as stagefright/1.2 (Linux;Android 5.0). Use Wireshark to debug requests (as I did) if Google's servers are not responding, and ensure that these headers are being set properly in the GET! Google will respond with a 503 Service Unavailable if the request fails, followed by a redirect to the CAPTCHA page.

This solution is a bit brittle; it is entirely possible that Google will change the way they handle these requests in the future, so in the end I would suggest asking Google to make a real API endpoint (free or paid) that we can use without feeling dirty for faking HTTP headers.

Edit 2: For those interested, this cURL command should work perfectly fine to download an mp3 of Hello in English:

curl 'http://translate.google.com/translate_tts?ie=UTF-8&q=Hello&tl=en&client=t' -H 'Referer: http://translate.google.com/' -H 'User-Agent: stagefright/1.2 (Linux;Android 5.0)' > google_tts.mp3

As you may notice, I have set both the Referer and User-Agent headers in the request, as well as added the client=t parameter to the querystring. You may use https instead of http, your choice!

Edit 3: Google now requires a token for each GET request (noted by tk in the querystring). Below is the revised cURL command that will correctly download a TTS mp3:

curl 'https://translate.google.com/translate_tts?ie=UTF-8&q=hello&tl=en&tk=995126.592330&client=t' -H 'user-agent: stagefright/1.2 (Linux;Android 5.0)' -H 'referer: https://translate.google.com/' > google_tts.mp3

Notice the &tk=995126.592330 in the querystring; this is the new token. I obtained this token by pressing the speaker icon on translate.google.com and looking at the GET request. I simply added this querystring parameter to the previous cURL command, and it works.

NOTE: obviously this solution is very frail, and breaks at the whim of the architects at Google who introduce new things like tokens required for the requests. This token may not work tomorrow (though I will check and report back)... the point is, it is not wise to rely on this method; instead, one should turn to a commercial TTS solution, especially if using TTS in production.

For further explanation of the token generation and what you might be able to do about it, see Boude's answer.

If this solution breaks any time in the future, please leave a comment on this answer so that we can attempt to find a fix for it!

Expanding on Chris' answer. I managed to reverse engineer the token generation process.

The token for the request is based on the text and a global TKK variable set in the page script. These are hashed in JavaScript thus resulting in the tk param.

Somewhere in the page script you will find something like this:

TKK='403413';

This is the amount of hours passed since epoch.

The text is pumped in the following function (somewhat deobfuscated):

var query = "Hello person";
var cM = function(a) {
    return function() {
        return a
    }
};
var of = "=";
var dM = function(a, b) {
    for (var c = 0; c < b.length - 2; c += 3) {
        var d = b.charAt(c + 2),
            d = d >= t ? d.charCodeAt(0) - 87 : Number(d),
            d = b.charAt(c + 1) == Tb ? a >>> d : a << d;
        a = b.charAt(c) == Tb ? a + d & 4294967295 : a ^ d
    }
    return a
};

var eM = null;
var cb = 0;
var k = "";
var Vb = "+-a^+6";
var Ub = "+-3^+b+-f";
var t = "a";
var Tb = "+";
var dd = ".";
var hoursBetween = Math.floor(Date.now() / 3600000);
window.TKK = hoursBetween.toString();

fM = function(a) {
    var b;
    if (null === eM) {
        var c = cM(String.fromCharCode(84)); // char 84 is T
        b = cM(String.fromCharCode(75)); // char 75 is K
        c = [c(), c()];
        c[1] = b();
        // So basically we're getting window.TKK
        eM = Number(window[c.join(b())]) || 0
    }
    b = eM;

    // This piece of code is used to convert d into the utf-8 encoding of a
    var d = cM(String.fromCharCode(116)),
        c = cM(String.fromCharCode(107)),
        d = [d(), d()];
    d[1] = c();
    for (var c = cb + d.join(k) +
            of, d = [], e = 0, f = 0; f < a.length; f++) {
        var g = a.charCodeAt(f);

        128 > g ? d[e++] = g : (2048 > g ? d[e++] = g >> 6 | 192 : (55296 == (g & 64512) && f + 1 < a.length && 56320 == (a.charCodeAt(f + 1) & 64512) ? (g = 65536 + ((g & 1023) << 10) + (a.charCodeAt(++f) & 1023), d[e++] = g >> 18 | 240, d[e++] = g >> 12 & 63 | 128) : d[e++] = g >> 12 | 224, d[e++] = g >> 6 & 63 | 128), d[e++] = g & 63 | 128)
    }


    a = b || 0;
    for (e = 0; e < d.length; e++) a += d[e], a = dM(a, Vb);
    a = dM(a, Ub);
    0 > a && (a = (a & 2147483647) + 2147483648);
    a %= 1E6;
    return a.toString() + dd + (a ^ b)
};

var token = fM(query);
var url = "https://translate.google.com/translate_tts?ie=UTF-8&q="  + encodeURI(query) + "&tl=en&total=1&idx=0&textlen=12&tk=" + token + "&client=t";
document.write(url);

I managed to successfully port this to python in my fork of gTTS, so I know this works.

Edit: By now the token generation code used by gTTS has been moved into gTTS-token.

Edit 2: Google has changed the API (somewhere around 2016-05-10), this method requires some modification. I'm currently working on this. In the meantime changing the client to tw-ob seems to work.

Edit 3:

The changes are minor, yet annoying to say the least. The TKK now has two parts. Looking something like 406986.2817744745. As you can see the first part has remained the same. The second part is the sum of two seemingly random numbers. TKK=eval('((function(){var a\x3d2680116022;var b\x3d137628723;return 406986+\x27.\x27+(a+b)})())'); Here \x3d means = and \x27 is '. Both a and b change every UTC minute. At one of the final steps in the algorithm the token is XORed by the second part.

The new token generation code is:

var xr = function(a) {
    return function() {
        return a
    }
};
var yr = function(a, b) {
    for (var c = 0; c < b.length - 2; c += 3) {
        var d = b.charAt(c + 2)
          , d = "a" <= d ? d.charCodeAt(0) - 87 : Number(d)
          , d = "+" == b.charAt(c + 1) ? a >>> d : a << d;
        a = "+" == b.charAt(c) ? a + d & 4294967295 : a ^ d
    }
    return a
};
var zr = null;
var Ar = function(a) {
    var b;
    if (null  !== zr)
        b = zr;
    else {
        b = xr(String.fromCharCode(84));
        var c = xr(String.fromCharCode(75));
        b = [b(), b()];
        b[1] = c();
        b = (zr = window[b.join(c())] || "") || ""
    }
    var d = xr(String.fromCharCode(116))
      , c = xr(String.fromCharCode(107))
      , d = [d(), d()];
    d[1] = c();
    c = "&" + d.join("") + 
    "=";
    d = b.split(".");
    b = Number(d[0]) || 0;
    for (var e = [], f = 0, g = 0; g < a.length; g++) {
        var l = a.charCodeAt(g);
        128 > l ? e[f++] = l : (2048 > l ? e[f++] = l >> 6 | 192 : (55296 == (l & 64512) && g + 1 < a.length && 56320 == (a.charCodeAt(g + 1) & 64512) ? (l = 65536 + ((l & 1023) << 10) + (a.charCodeAt(++g) & 1023),
        e[f++] = l >> 18 | 240,
        e[f++] = l >> 12 & 63 | 128) : e[f++] = l >> 12 | 224,
        e[f++] = l >> 6 & 63 | 128),
        e[f++] = l & 63 | 128)
    }
    a = b;
    for (f = 0; f < e.length; f++)
        a += e[f],
        a = yr(a, "+-a^+6");
    a = yr(a, "+-3^+b+-f");
    a ^= Number(d[1]) || 0;
    0 > a && (a = (a & 2147483647) + 2147483648);
    a %= 1E6;
    return c + (a.toString() + "." + (a ^ b))
}
;
Ar("test");

Of course I can't generate a valid url anymore, since I don't know how a and b are generated.