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 alphanumeric strings, but can contain special characters such as quotes, spaces, etc.

What is the canonical way of doing this type of POST request in Qt?

Answer 1

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?

Answer 2

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)