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  4. [SOLVED] Empty QJsonDocument from file
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[SOLVED] Empty QJsonDocument from file

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  • N Offline
    N Offline
    ningu
    wrote on last edited by
    #3

    Thanks for the quick answer.

    Unfortunately, even though you are right, removing the superfluous comma did not solve the problem. The QDomDocument is still empty.

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    • N Offline
      N Offline
      ningu
      wrote on last edited by
      #4

      I think the error is in the loading of the file.
      @qDebug() << file.bytesAvailable();@

      outputs 0, although it seems to load fine (no error output).

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      • N Offline
        N Offline
        ningu
        wrote on last edited by
        #5

        If I load the data from the file to QDomDocument object it seems to work fine. I very puzzled.

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        • SGaistS Offline
          SGaistS Offline
          SGaist
          Lifetime Qt Champion
          wrote on last edited by
          #6

          Hi,

          Just to be on the safe side, did you properly put your json file in the resources (qrc file) ?

          You keep talking about QDomDocument, is it a typo ?

          Interested in AI ? www.idiap.ch
          Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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          • N Offline
            N Offline
            ningu
            wrote on last edited by
            #7

            Yes, the file is properly put in my qrc file.

            And yes, sorry, when I said

            bq. Unfortunately, even though you are right, removing the superfluous comma did not solve the problem. The QDomDocument is still empty.

            I meant the QJsonDocument is still empty.

            But later on I tried to load the data into a QDomDocument object just to try and it seems to work fine.
            @
            QDomDocument *domDocument;
            if (!domDocument->setContent(&file)) {
            qDebug() << "Could not set DOM";
            return;
            }

            qDebug() << domDocument->toString();@

            prints the file contents to the console.

            Sorry for the confusion I created with the typo.

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            • SGaistS Offline
              SGaistS Offline
              SGaist
              Lifetime Qt Champion
              wrote on last edited by
              #8

              Ok, then what does

              @qDebug() << file.readAll()@

              return ?

              Interested in AI ? www.idiap.ch
              Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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              • N Offline
                N Offline
                ningu
                wrote on last edited by
                #9

                It returns
                @""@

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                • SGaistS Offline
                  SGaistS Offline
                  SGaist
                  Lifetime Qt Champion
                  wrote on last edited by
                  #10

                  Then it seems that your file is empty

                  Interested in AI ? www.idiap.ch
                  Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                  • N Offline
                    N Offline
                    ningu
                    wrote on last edited by
                    #11

                    That's what I thought, but
                    @qDebug() << QString::fromUtf8(file.readAll())@
                    returns the file contents.

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                    • N Offline
                      N Offline
                      ningu
                      wrote on last edited by
                      #12

                      Might it be an encoding issue?

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                      • N Offline
                        N Offline
                        ningu
                        wrote on last edited by
                        #13

                        Sorry, that was not completely right:
                        @QString jsonString = QString::fromUtf8(file.readAll());
                        qDebug() << jsonString;
                        @
                        returns the file contents, while
                        @qDebug() << QString::fromUtf8(file.readAll())@
                        returns
                        @""@

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                        • SGaistS Offline
                          SGaistS Offline
                          SGaist
                          Lifetime Qt Champion
                          wrote on last edited by
                          #14

                          Strange, QJsonDocument should handle it...
                          Did you check what error you got when using fromJson ?

                          Interested in AI ? www.idiap.ch
                          Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                          • N Offline
                            N Offline
                            ningu
                            wrote on last edited by
                            #15

                            No, I didn't. How could I do that?

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                            • N Offline
                              N Offline
                              ningu
                              wrote on last edited by
                              #16

                              Ok, I got it. A friend of mine pointed me out that I was looking for the array in the QJsonDocument, and that I should probably be looking for the object, which worked.

                              The only thing that doesn't work right is that
                              @QString jsonString = QString::fromUtf8(file.readAll());

                              QJsonDocument jsonDoc = QJsonDocument::fromJson(jsonString.toUtf8());@
                              works, but
                              @QJsonDocument jsonDoc = QJsonDocument::fromJson(file.readAll());@
                              doesn't.

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                              • SGaistS Offline
                                SGaistS Offline
                                SGaist
                                Lifetime Qt Champion
                                wrote on last edited by
                                #17

                                Look at the second parameter of "fromJson":http://qt-project.org/doc/qt-5.0/qtcore/qjsondocument.html#fromJson

                                From there you can get the error

                                Interested in AI ? www.idiap.ch
                                Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                                • N Offline
                                  N Offline
                                  ningu
                                  wrote on last edited by
                                  #18

                                  It's an 'Illegal value' error. But I get the same error even with an empty file.

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                                  • SGaistS Offline
                                    SGaistS Offline
                                    SGaist
                                    Lifetime Qt Champion
                                    wrote on last edited by
                                    #19

                                    Could it be your json file encoding that is problematic ?

                                    Interested in AI ? www.idiap.ch
                                    Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                                    • N Offline
                                      N Offline
                                      ningu
                                      wrote on last edited by
                                      #20

                                      That might be it. Is there a way to make sure the file is UTF8? Or set it to UTF8?

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                                      • SGaistS Offline
                                        SGaistS Offline
                                        SGaist
                                        Lifetime Qt Champion
                                        wrote on last edited by
                                        #21

                                        If you are using QtCreator you could check the editor settings to ensure that it uses UTF8

                                        Interested in AI ? www.idiap.ch
                                        Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                                        • N Offline
                                          N Offline
                                          ningu
                                          wrote on last edited by
                                          #22

                                          Ah, that did it!

                                          Thank you very much for all your help SGaist!

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