Make HTTP POST request with a list of named parameters in Qt

Question

I need to make an HTTP POST request to a server from my Qt application.

The POST request would contain a list of named values, i.e. key/value pairs. They will be mostly

Answer 1

QUrl params;

params.addQueryItem("key1", "value1");
params.addQueryItem("key2", "value2");

QUrl resource("http://server.com/form.php");
QNetworkAccessManager* manager = new QNetworkAccessManager(this);

connect(manager, SIGNAL(finished(QNetworkReply*)), this, SLOT(handleEndOfRequest(QNetworkReply*)));

QNetworkRequest request(resource);
//Force Content-Type header
request.setHeader(QNetworkRequest::ContentTypeHeader, "application/x-www-form-urlencoded");

manager->post(request, params.encodedQuery());

This code assumes that your current object is a QObject (passed as a parent for QNeworkAccessManager and slots declaration)

Answer 2

You can use QNetworkAccessManager together with QNetworkRequest to post http requests.
If you want to send key/value pairs, consider using JSON.

Answer 3

The current answer works for Qt 4. Syntax has changed for Qt 5 and would look like this:

QUrlQuery params;

params.addQueryItem("key1", "value1");
params.addQueryItem("key2", "value2");

QUrl resource("http://server.com/form.php");
QNetworkAccessManager* manager = new QNetworkAccessManager(this);

connect(manager, SIGNAL(finished(QNetworkReply*)), this, 
SLOT(handleEndOfRequest(QNetworkReply*)));

QNetworkRequest request(resource);
//Force Content-Type header
request.setHeader(QNetworkRequest::ContentTypeHeader, "application/x-www-form-urlencoded");

manager->post(request, params.query(QUrl::FullyEncoded).toUtf8());

Some background information: http://doc.qt.io/qt-5/qurl-obsolete.html

Making Qt-version-aware code is described here: How do you port QUrl addQueryItem to Qt5's QUrlQuery?