Google Translate API v2, v3 PHP

Question

I just started using the BING translate API to do a small volume of translations into most of their supported languages and that works pretty well.

There is a GitHub project that has simple PHP code for making the API call to Microsoft. You mostly just need the API key, and it can be customized pretty easily.

Text-Translation-API-V3-PHP

// NOTE: Be sure to uncomment the following line in your php.ini file.
// ;extension=php_openssl.dll
// **********************************************
// *** Update or verify the following values. ***
// **********************************************
// Replace the subscriptionKey string value with your valid subscription key.
$key = 'ENTER KEY HERE';
$host = "https://api.cognitive.microsofttranslator.com";
$path = "/translate?api-version=3.0";

// Translate to German and Italian.
$params = "&to=de&to=it";
$text = "Hello, world!";

if (!function_exists('com_create_guid')) {
  function com_create_guid() {
    return sprintf( '%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
        mt_rand( 0, 0xffff ), mt_rand( 0, 0xffff ),
        mt_rand( 0, 0xffff ),
        mt_rand( 0, 0x0fff ) | 0x4000,
        mt_rand( 0, 0x3fff ) | 0x8000,
        mt_rand( 0, 0xffff ), mt_rand( 0, 0xffff ), mt_rand( 0, 0xffff )
    );
  }
}

function Translate ($host, $path, $key, $params, $content) {
    $headers = "Content-type: application/json\r\n" .
        "Content-length: " . strlen($content) . "\r\n" .
        "Ocp-Apim-Subscription-Key: $key\r\n" .
        "X-ClientTraceId: " . com_create_guid() . "\r\n";
    // NOTE: Use the key 'http' even if you are making an HTTPS request. See:
    // http://php.net/manual/en/function.stream-context-create.php
    $options = array (
        'http' => array (
            'header' => $headers,
            'method' => 'POST',
            'content' => $content
        )
    );
    $context  = stream_context_create ($options);
    $result = file_get_contents ($host . $path . $params, false, $context);
    return $result;
}

$requestBody = array (
    array (
        'Text' => $text,
    ),
);
$content = json_encode($requestBody);
$result = Translate ($host, $path, $key, $params, $content);
// Note: We convert result, which is JSON, to and from an object so we can pretty-print it.
// We want to avoid escaping any Unicode characters that result contains. See:
// http://php.net/manual/en/function.json-encode.php
$json = json_encode(json_decode($result), JSON_UNESCAPED_UNICODE | JSON_PRETTY_PRINT);
echo $json;

I also have a Google Cloud account and am looking for something similar for a few languages that Google supports that BING does not. For v2, it is not too hard to call Google to make the return the translations.

I found this GitHub project that seems to work for v2 API calls with an API key, but unfortunately I think that is a fee-for-service program now ?

google-cloud-php-translate

That also seems to work pretty well if you have an API key. If you are using v3, they apparently updated the libraries and support. You can make a CURL call from the command line and they have some of that documented on their website, but I am looking for a way to make the call using a PHP file.

require 'vendor/autoload.php';   
use Google\Cloud\Translate\TranslateClient;

$translate = new TranslateClient([
    'key' => 'APIKEY'
]);

// Translate text from english to french.
$result = $translate->translate('Hello world!', [
    'target' => 'fr'
]);

echo $result['text'] . "\n";

// Detect the language of a string.
$result = $translate->detectLanguage('Greetings from Michigan!');

echo $result['languageCode'] . "\n";

// Get the languages supported for translation specifically for your target language.
$languages = $translate->localizedLanguages([
    'target' => 'en'
]);

foreach ($languages as $language) {
    echo $language['name'] . "\n";
    echo $language['code'] . "\n";
}

// Get all languages supported for translation.
$languages = $translate->languages();

foreach ($languages as $language) {
    echo $language . "\n";
}

Not sure that is even possible, but the best I can come up with is something like this based upon the command line CURL, but the authentication is wrong and fails. I do have the .json file for my Project/Service credentials. The ${PROJECT_ID} I presume is the project ID for the account, and Bearer $(gcloud auth application-default print-access-token) I am not sure about. There are some instructions about how to obtain that through the CLI, but is there a way to get that via a PHP file ? Like I say, the v2 version works fine.

$ch = curl_init();   
curl_setopt($ch, CURLOPT_URL, "https://translation.googleapis.com/v3beta1/projects/${PROJECT_ID}/locations/global:detectLanguage");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, "{\n     mimeType: 'text/plain',\n     content: 'Omnia Gallia est divisa in tres partes'\n}");
curl_setopt($ch, CURLOPT_POST, 1);

$headers = array();
$headers[] = 'Authorization: Bearer $(gcloud auth application-default print-access-token)';
$headers[] = 'Content-Type: application/json';
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);

$result = curl_exec($ch);
if (curl_errno($ch)) {
    echo 'Error:' . curl_error($ch);
} else {
    echo $result;
}
curl_close ($ch);

There might be clues here, but it talks about exporting the path for the credentials file and running PHP scripts from the command line instead of from a server.

Google Cloud Translate API Samples

Answer 1

This probably won't evaluate:

'Authorization: Bearer $(gcloud auth application-default print-access-token)'

It's rather:

// $cmd = 'gcloud auth application-default login';
$cmd = 'gcloud auth application-default print-access-token';
$token = shell_exec($cmd);

besides it probably should be a service account.

It seems google/cloud replaces google/cloud-translate. For Translate, you could edit the translate-v2.json or add translate-v3beta1.json; but v3beta1 has a whole other REST API than v2 ...

Answer 2

I have an irrational dislike for using client libraries, so I didn't install the Google PHP library. From what I can tell, the only way to get the authentication to work is to actually go through the whole Oauth2 process. I think the PHP library handles some of that for you, but this code should work as a standalone solution.

First, make sure you've got your Google Cloud Platform account set up, then create a project, then enable the Translation API, after that, create and configure an API key before creating and configuring an OAuth 2.0 client (make sure you enter the correct redirect url). Nothin' to it! ;-)

If you succeed in getting all of that squared away, you should be good to go!

The page effectively redirects the user to the same page they were just on, but includes the results of a GET request in the url. The response contains a code, that can be used to make another GET request in order to retrieve the access token, and once you've got the access token, you can make a POST request to perform the actual translation.

<?php

$clientId = "{your client id}";
$clientSecret = "{your client secret}";
$clientRedirectURL = "{your redirect URL}";
$login_url = 'https://accounts.google.com/o/oauth2/v2/auth?scope=' . urlencode('https://www.googleapis.com/auth/userinfo.profile https://www.googleapis.com/auth/userinfo.email https://www.googleapis.com/auth/cloud-translation') . '&redirect_uri=' . urlencode($clientRedirectURL) . '&response_type=code&client_id=' . $clientId . '&access_type=online';

if (!isset($_GET['code'])){
    header("location: $login_url");
} else {
    $code = filter_var($_GET['code'], FILTER_SANITIZE_STRING);  
    $curlGet = '?client_id=' . $clientId . '&redirect_uri=' . $clientRedirectURL . '&client_secret=' . $clientSecret . '&code='. $code . '&grant_type=authorization_code';
    $url = 'https://www.googleapis.com/oauth2/v4/token' . $curlGet;

    $ch = curl_init($url);      
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);        
    curl_setopt($ch, CURLOPT_POST, 1);      
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
    $data = curl_exec($ch); 
    $data = json_decode($data, true);   
    curl_close($ch);

    $accessToken = $data['access_token'];
    $apiKey = "{your api key}";
    $projectID = "{your project id}";

    $target = "https://translation.googleapis.com/v3/projects/$projectID:translateText?key=$apiKey";

    $headers = array( 
        "Content-Type: application/json; charset=utf-8", 
        "Authorization: Bearer " . $accessToken,
        "x-goog-encode-response-if-executable: base64",
        "Accept-language: en-US,en;q=0.9,es;q=0.8"
    );

    $requestBody = array();
    $requestBody['sourceLanguageCode'] = "en";
    $requestBody['targetLanguageCode'] = "pt";
    $requestBody['contents'] = array("So, I guess this thing works?");
    $requestBody['mimeType'] = "text/plain";

    $ch = curl_init($target);
    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers); 
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); 
    curl_setopt($ch, CURLOPT_POST, true);
    curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($requestBody)); 
    $data = curl_exec($ch);

    curl_close($ch);
    echo $data;
}

Also, I found this tutorial quite helpful.