How to use Google Translate API With c++ - c++

Question

I'm a beginner in C++ and using Google task API.
How do I write a C++ program that accepts a word, then invokes Google Translate to translate it from English to French, then saves the resulted page to a local file?
For example, if the user inputs "river", the program should invoke Google Translate to translate into French, the resulting page is:
http://translate.google.com/#en|fr|River%0A
This page should be saved.
I read the official documentation through fully: http://code.google.com/apis/language/translate/v2/getting_started.html
but I couldn't understand how to using REST and I'm not familiar with JSON or AJAX.

Answer 1

You cannot use JSON objects straight in C++.
JSON = JavaScript Object Notation
You need to spawn/create something which can parse such objects. For example I've used QNetworkManager in Qt (in C++) to send build javascript and send requests to google APIs. The result would be a JSON object which I had to parse and either display in a browser (which I made in c++) or parse the results into a c++ class and process it differently (do some calculations with it).
If you just need the data, you can request XML instead of JSON and then you can use a standard XML parser to extract the translated word.
EDIT 1:
Google in their example uses:
https://www.googleapis.com/language/translate/v2?key=YOUR-API-KEY&source=en&target=de&q=words+to+translate
This translate from english (en) to german (de). The words to translate are: "words to translate".
Now build an HTTP request in C++ with this URL as the data. Send that with some network manager or sockets and wait for a reply back. Google will give you back data.

Answer 2

I seen this codes below somewhere but I don't remember where, anyway try this:
QString YourClass::translate(QString keyword, QString from, QString to)
{
//Translate URL
QString url = QString("http://translate.google.com/translate_a/t?client=t&text=%0&hl=%1&sl=%2&tl=%1&multires=1&prev=enter&oc=2&ssel=0&tsel=0&uptl=%1&sc=1").arg(keyword).arg(to).arg(from);
QNetworkAccessManager manager;
QNetworkRequest request(url);
QNetworkReply *reply = manager.get(request);
//Get reply from Google
do {
QCoreApplication::processEvents(QEventLoop::ExcludeUserInputEvents);
} while(!reply->isFinished());
//Convert to string
QString translation(reply->readAll());
reply->close();
//Free memory
delete reply;
//Remove [[[" from the beginning
translation = translation.replace("[[[\"", "");
//Extract final translated string
translation = translation.mid(0, translation.indexOf(",\"") - 1);
return translation;
}

Answer 3

someone advise me to use libcurl, I will try and see.

Answer 4

You need some kind of HTTP library. I second most of what Adrian said, but here's some (incomplete) Qt code which should give you an idea.
namespace {
const QString API_KEY = /* TODO */;
}
MyQObject :: MyQbject ()
: m_manager (new QNetworkAccessManager (this))
{
connect(manager, SIGNAL (finished (QNetworkReply *)),
this, SLOT (reply_finished (QNetworkReply *)));
}
void MyQObject :: fetch_translation (
QString words,
void (*on_receive)(const QString &))
{
// Let's assume asynchronous but non-concurrent requests.
m_on_receive = on_receive;
QString request =
"https://www.googleapis.com/language/translate/v2"
"?key=%1&source=en&target=de&q=%2";
// May want to url-encode 'words' first.
m_manager -> get (QUrl (request .arg (API_KEY) .arg (words));
}
void MyQObject :: reply_finished (QNetworkReply * reply)
{
m_on_receive (reply -> readAll ());
}
// ...
{
my_q_object -> translate ("hello, world", [](const QString & s) {
qWarning () << "translation is: " << s;
});
}