QNetworkAccessManager - finished signal (when emitted)



  • I have a REST-service which i access using an HTTP POST. Using soap ui, i get timings like 30 ms. When using QNetworkaccessmanager (connecting the finished signal, direct connection) i get 230 ms.

    I used wireshark to check what is going on...

    What i see is that both ways are sending the same messages:

    • TCP SYN (time: 15.9528600)
    • TCP SYN, ACK (time: 15.9536980)
    • ACK (time: 15.9537440)
    • HTTP POST (time: 15.9549770)
    • HTTP REPLY (time: 15.9998710)
    • TCP ACK (time: 16.1998570) --> the time difference between the last HTTP reply and the ack is +/- 200 ms...

    The question is, is the finished signal emitted after the TCP ack in QNetworkAccessManager and can i force the signal to be emitted faster? Is it normal it waits to ack the reply before sending the finished signal? If so, is there another signal i can use to get the reply sooner?

    Or am I doing it wrong?

    Part of code:

    _am = new QNetworkAccessManager();
    connect( _am, SIGNAL( finished( QNetworkReply* ) ), this, SLOT( _requestFinished( QNetworkReply* ) ), Qt::DirectConnection );
    ...
    QNetworkRequest request( _requestData.url );
    request.setHeader( QNetworkRequest::ContentTypeHeader,"application/json" );
     _elapsed.restart();
    _reply = _am->post( request, _requestData.data );
    

    I time using QElapsedTimer just before doing the post and within the _requestFinished slot i take the elapsed time and output it.
    I always see 200+ ms...

    Any help? Or ideas?

    Thanks in advance.


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