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Reading a file with Qt

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  • E Offline
    E Offline
    EL-jos
    wrote on last edited by EL-jos
    #13

    Concretely I want my client to send a file to my server and the server after receiving the file, that it sends this file to all the client that are connected to it.
    Because it is a chat software then I also want the client to be able to send a file to another client via a server.

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    • Christian EhrlicherC Offline
      Christian EhrlicherC Offline
      Christian Ehrlicher
      Lifetime Qt Champion
      wrote on last edited by
      #14

      Please take a look at the examples (again...) how to send large data ... http://doc.qt.io/qt-5/qtnetwork-loopback-example.html

      Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
      Visit the Qt Academy at https://academy.qt.io/catalog

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      • E Offline
        E Offline
        EL-jos
        wrote on last edited by
        #15

        Okay Thanks, I'll read this example and then I'll come back to you to give you the follow-up.

        Thank you

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        • E Offline
          E Offline
          EL-jos
          wrote on last edited by
          #16

          Hi,
          after several studies of the example given by the Qt documentation, I don't know where and how to send my file to the server?

          then in the example given by the Qt documentation, just sends the same 64KB packet several times until it tints 50MB . and the server and the client are in the same project but in my case the client and the server are different projects

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

            Hi,

            Are you writing both the client and server parts ?

            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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            • E Offline
              E Offline
              EL-jos
              wrote on last edited by
              #18

              Yes, do you want me to mail them?

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

                It was regarding your last remark about the server and client being in the same project. Since you are writing both, then it doesn't matter that they are in different projects.

                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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                • E Offline
                  E Offline
                  EL-jos
                  wrote on last edited by
                  #20

                  Hey, everybody,

                  Still in the example given by the Qt documentation for the exchange of large documents between the client and the server in a chatt software, I could separate the client and the server in different projects which is not the case in the example given by the Qt documentation.

                  So here's my question:

                  Just that there I do not know how to adapt this example to my chatt software to be able to send large files between client and server?

                  Translated with www.DeepL.com/Translator

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

                    There's nothing special to do, if you implement the client and the server the same way as the exemple, then it's also going to work the same.

                    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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                    • E Offline
                      E Offline
                      EL-jos
                      wrote on last edited by
                      #22

                      Theoretically yes, but in practice this is not the case.

                      mrjjM 1 Reply Last reply
                      0
                      • E EL-jos

                        Theoretically yes, but in practice this is not the case.

                        mrjjM Offline
                        mrjjM Offline
                        mrjj
                        Lifetime Qt Champion
                        wrote on last edited by
                        #23

                        @EL-jos
                        Hi
                        As mr @Christian-Ehrlicher noted higher up.
                        You are using quint16 for size handling
                        Try
                        #include <limits.h>
                        qDebug() << std::numeric_limits<quint16>::max();

                        and you will see the magic 65535 as maximum value.

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                        • E Offline
                          E Offline
                          EL-jos
                          wrote on last edited by
                          #24

                          Yes you are right but except that 65535 makes a maximum size of 64Ko or me I want to send voluminous documents of the order of 30Mo to even 50Mo

                          mrjjM JKSHJ 2 Replies Last reply
                          0
                          • E EL-jos

                            Yes you are right but except that 65535 makes a maximum size of 64Ko or me I want to send voluminous documents of the order of 30Mo to even 50Mo

                            mrjjM Offline
                            mrjjM Offline
                            mrjj
                            Lifetime Qt Champion
                            wrote on last edited by
                            #25

                            @EL-jos
                            then use quint64 instead.

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                            • E EL-jos

                              Yes you are right but except that 65535 makes a maximum size of 64Ko or me I want to send voluminous documents of the order of 30Mo to even 50Mo

                              JKSHJ Offline
                              JKSHJ Offline
                              JKSH
                              Moderators
                              wrote on last edited by JKSH
                              #26

                              @EL-jos said in Reading a file with Qt:

                              65535 makes a maximum size of 64Ko or me I want to send voluminous documents of the order of 30Mo to even 50Mo

                              Then you cannot use quint16. It is too small.

                              Use quint32 or even quint64 instead.

                              EDIT: @mrjj beat me to it!

                              Qt Doc Search for browsers: forum.qt.io/topic/35616/web-browser-extension-for-improved-doc-searches

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                              • E Offline
                                E Offline
                                EL-jos
                                wrote on last edited by
                                #27

                                Hey, everybody.
                                I was able to solve my problem thanks to your advice, now I am able to send large document in my chatt software but there is a new problem that arises, here is the problem: Which class should I use to send a video file in my chatt software?
                                Example: for image exchange, I used the class QImage(Stream for image)but now what class used for Video(Stream video)?

                                jsulmJ 1 Reply Last reply
                                0
                                • E EL-jos

                                  Hey, everybody.
                                  I was able to solve my problem thanks to your advice, now I am able to send large document in my chatt software but there is a new problem that arises, here is the problem: Which class should I use to send a video file in my chatt software?
                                  Example: for image exchange, I used the class QImage(Stream for image)but now what class used for Video(Stream video)?

                                  jsulmJ Offline
                                  jsulmJ Offline
                                  jsulm
                                  Lifetime Qt Champion
                                  wrote on last edited by jsulm
                                  #28

                                  @EL-jos If it is a file then simply send the binary content of the file.
                                  There is no need to use a dedicated class for each and every data type.
                                  https://stackoverflow.com/questions/30288385/how-to-send-a-file-in-qt

                                  https://forum.qt.io/topic/113070/qt-code-of-conduct

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                                  3
                                  • E Offline
                                    E Offline
                                    EL-jos
                                    wrote on last edited by
                                    #29

                                    Yes it is already what I do so I send data in bytes but except that it does not work because I have an error when reading my file like this file is not supported

                                    jsulmJ 1 Reply Last reply
                                    0
                                    • aha_1980A Offline
                                      aha_1980A Offline
                                      aha_1980
                                      Lifetime Qt Champion
                                      wrote on last edited by
                                      #30

                                      @EL-jos

                                      Why should a file not be supported if you just send it byte-by-byte? if you store it on a harddisk, it does not matter for the hard disk which file type it is. Its just a number of bytes.

                                      Same happens when you send it over network.

                                      Regards

                                      Qt has to stay free or it will die.

                                      1 Reply Last reply
                                      1
                                      • E EL-jos

                                        Yes it is already what I do so I send data in bytes but except that it does not work because I have an error when reading my file like this file is not supported

                                        jsulmJ Offline
                                        jsulmJ Offline
                                        jsulm
                                        Lifetime Qt Champion
                                        wrote on last edited by
                                        #31

                                        @EL-jos said in Reading a file with Qt:

                                        error when reading my file like this file is not supported

                                        Please explain. Where do you get this error? QFile (I guess you use it for reading) does not care at all about file content.

                                        https://forum.qt.io/topic/113070/qt-code-of-conduct

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                                        1
                                        • E Offline
                                          E Offline
                                          EL-jos
                                          wrote on last edited by
                                          #32

                                          In fact after the client sends the byte array, the server receives the bytes and Opens a file in write only mode and writes all the bytes received but except that if I try via VLC to read this file, there is a message that appears like this file is not supported

                                          jsulmJ JonBJ 2 Replies Last reply
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