POST using Qt5

[rosetter]

I'm stumbling my way through communicating with a web service and failing badly.. I'm trying to mimic a form that POSTs a chunk of json data to the server in a "json" field. There are similar questions here on Qt Project and elsewhere, but most are using the 4.x APIs which don't translate directly. Help!

Here's what I'm trying (simplified a little):

@
QUrl url("http://.....");
QUrlQuery query;
query.addQueryItem("json", <json text as QString>);
url.setQuery(query);
QNetworkRequest request(url);
request.setHeader(QNetworkRequest::ContentTypeHeader, "application/x-www-form-urlencoded");
QNetworkAccessManager net(this);
net.get(request);
@

It seems strange to be using "get" to POST data... also the docs suggest that addQueryItem() does not do what a browser would do with a form (converting spaces to pluses) but doesn't give any advice on whether that is important or not.

Any help would be most appreciated!

[raven-worx]

[quote author="rosetter" date="1389792547"]
It seems strange to be using "get" to POST data...
[/quote]
Indeed, where to you got this example from?!

@
QByteArray postData;
postData.append("json=<json-data>&");
postData.append("other=<other-data>");

QNetworkRequest request( QUrl("...") );
        request.setHeader(QNetworkRequest::ContentTypeHeader, "application/x-www-form-urlencoded");

QNetworkAccessManager* net = ...;
QNetworkReply* reply = net->post(request, postData);
connect(reply, SIGNAL(...), ..., SLOT(...);

@
Make sure you use a QNetworkAccessManager by pointer value, or as class member. Just not in a stack variable with function scope...

[rosetter]

Hi, thanks for the quick reply! Unfortunately I'm still super-confused..

• do I need to do some kind of encoding of postData? (% encoding? space -> '+'?)
• what about QUrlQuery? is it not intended to be helpful in POSTs?
• is there some way I can see what is actually being sent over the network?

[raven-worx]

[quote author="rosetter" date="1389970769"]

• do I need to do some kind of encoding of postData? (% encoding? space -> '+'?)
• what about QUrlQuery? is it not intended to be helpful in POSTs?
  [/quote]
  yes you would need to do the encoding yourself. But still you can use QUrlQuery::query().

[quote author="rosetter" date="1389970769"]

• is there some way I can see what is actually being sent over the network?
  [/quote]
  Not on Qt level. You can use a proxy/sniffer application like "wireshark":http://www.wireshark.org.