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Extending networking/socket programming functionality of a qml project

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  • Q Offline
    Q Offline
    qcoderpro
    wrote on last edited by
    #8

    @SGaist

    You have an architectural issue here. You will try to connect to a server which might change IP address at any time.

    Does it mean that from the time the server provides us with the IP (and port) on, that IP ( and port) may change and not usable by the client? Is it because the IP is public and non-static, so it can change at any given second?

    You also need a secondary communication channel to share said address as well as port number. Secondary channel that you will have to use pretty regularly in order to be able to keep the communication going.

    Does it mean that such a channel will keep the IP (and port) static to be usable on the client side? If so, what is that channel,please?

    Also, what about messages that cannot reach the other phone because its offline, out of network access, etc ?

    For simplicity reasons, we try to keep both users online throughout our connection for testing it.

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    • VRoninV VRonin

      @qcoderpro said in Extending networking/socket programming functionality of a qml project:

      you install one of the apps on your Android device and send the other to your friend in another city and you two can exchange messages together

      Unless you relax the security settings of one of the devices this will not work. You'll need a central server. This is not a restriction of the Qt framework, it's how all chatting applications work (the most famous messaging apps show the famous "double tick", one tick when the central server receives it, one tick when the second person receives the message).

      You can also take a look at https://wiki.qt.io/WIP-How_to_create_a_simple_chat_application where the chat logic is separate from the UI so it's easier to just replace the UI in QML. In any case you will need a server application that lives in a machine that is set up to accept incoming connection from the internet (client machines usually can't for security reason) and 2 clients that connect to it

      Q Offline
      Q Offline
      qcoderpro
      wrote on last edited by
      #9

      @VRonin

      Unless you relax the security settings of one of the devices this will not work. You'll need a central server. This is not a restriction of the Qt framework, it's how all chatting applications work (the most famous messaging apps show the famous "double tick", one tick when the central server receives it, one tick when the second person receives the message).

      Does it also mean that for such a simple communication (exchanging string messages) through global Internet we need a static IP/central sever? (like what SGaist believes I guess.)

      Also, thank you both for your links to those two examples, but consider my current situation, please.
      My two QML projects (with 3 files for each: .h, .cpp, and .qml - totally 6 files) contain nearly half the number of code lines of the two QWidget Fortune client/server projects, while the qml projects are different in two aspects:
      1- the sender is able to send any string message to the receiver
      2- the receiver is also able to send messages back.
      It was a huge jump in my socket programming/networking learning journey, a great part of which was possible because of your help.
      I took a look at the two links you sent me and they are undoubtedly very worthwhile I'm sure, but they're also very vast and huge for my current level! :(
      I decided to step forward and learn new things step-by-step. After gaining a goal in my projects, I like to extend them only one step more each time. That way I guess I can make progress better and easier without being bewildered and confused with lots of new and complicated code.
      I hope you understand me. :)

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

        Here is the thing: network programming is not simple as soon as you put internet in the mix.

        Hence, taking the time to study more complexe but detailed examples will help you faster than trying to make things work in a complexe setup. The chat is a good example: simple implementation for local networks, it requires more bricks when you start making a service that shall work across networks on different devices.

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

        Q 1 Reply Last reply
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        • SGaistS SGaist

          Here is the thing: network programming is not simple as soon as you put internet in the mix.

          Hence, taking the time to study more complexe but detailed examples will help you faster than trying to make things work in a complexe setup. The chat is a good example: simple implementation for local networks, it requires more bricks when you start making a service that shall work across networks on different devices.

          Q Offline
          Q Offline
          qcoderpro
          wrote on last edited by
          #11

          @SGaist

          Here is the thing: network programming is not simple as soon as you put internet in the mix.
          Hence, taking the time to study more complexe but detailed examples will help you faster than trying to make things work in a complexe setup. The chat is a good example: simple implementation for local networks, it requires more bricks when you start making a service that shall work across networks on different devices.

          Yeah, sure. I understand and will certainly study that chat example in near future, but for now I just like to extend my two projects so that they can work through global Internet.

          Will you answer the questions I asked above, please? They're important for me.

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          • SGaistS Offline
            SGaistS Offline
            SGaist
            Lifetime Qt Champion
            wrote on last edited by
            #12

            Static address is not required if you have a DNS resolvable name.

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

            Q 1 Reply Last reply
            2
            • VRoninV Offline
              VRoninV Offline
              VRonin
              wrote on last edited by
              #13

              Your problem is not an application one (if it works over LAN it means that you programmed it correctly), it’s an infrastructure one.
              If you don’t have one of the two devices set up to accept incoming connections and with a way to know what IP address to connect to (via either static ip or registering with a DNS) then you can’t do it.
              Neither of these conditions, however, depend on the application code, it’s just device setup

              "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
              ~Napoleon Bonaparte

              On a crusade to banish setIndexWidget() from the holy land of Qt

              1 Reply Last reply
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              • SGaistS SGaist

                Static address is not required if you have a DNS resolvable name.

                Q Offline
                Q Offline
                qcoderpro
                wrote on last edited by
                #14

                @SGaist

                Static address is not required if you have a DNS resolvable name.

                Although I've forgotten most of the things from university lessons (years ago) but yet can recall that a DNS works much like a phone book by managing the mapping between names and numbers. Do you mean that I need to setup a DNS resolvable name? Will you recommend a tutorial on this please?

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                • SGaistS Offline
                  SGaistS Offline
                  SGaist
                  Lifetime Qt Champion
                  wrote on last edited by
                  #15

                  Nobody suggested that you install a DNS server. You need to get an address from example from noip or another service.

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

                  Q 1 Reply Last reply
                  1
                  • SGaistS SGaist

                    Nobody suggested that you install a DNS server. You need to get an address from example from noip or another service.

                    Q Offline
                    Q Offline
                    qcoderpro
                    wrote on last edited by qcoderpro
                    #16

                    @SGaist
                    Aha, you mean to get an IP address from noip.com for instance, or another website like that.
                    But how that IP address will work on my projects, please?

                    jsulmJ 1 Reply Last reply
                    0
                    • Q qcoderpro

                      @SGaist
                      Aha, you mean to get an IP address from noip.com for instance, or another website like that.
                      But how that IP address will work on my projects, please?

                      jsulmJ Offline
                      jsulmJ Offline
                      jsulm
                      Lifetime Qt Champion
                      wrote on last edited by
                      #17

                      @qcoderpro said in Extending networking/socket programming functionality of a qml project:

                      But how that IP address will work on my projects, please?

                      Your device will get the IP at runtime using DNS.
                      If you access www..google..com you also do not enter an IP, right? But in the background your machine gets the IP for www..google..com via DNS.

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

                      Q 1 Reply Last reply
                      1
                      • jsulmJ jsulm

                        @qcoderpro said in Extending networking/socket programming functionality of a qml project:

                        But how that IP address will work on my projects, please?

                        Your device will get the IP at runtime using DNS.
                        If you access www..google..com you also do not enter an IP, right? But in the background your machine gets the IP for www..google..com via DNS.

                        Q Offline
                        Q Offline
                        qcoderpro
                        wrote on last edited by
                        #18

                        @jsulm
                        I mean, is the story this way?
                        When both projects are run, the server will get the IP address (provided by noip.com). The client also has that address (in its code) so it connects to it. Then they can exchanges messages.
                        Right?

                        If so, how about the port number!? Don't we need it?

                        jsulmJ 1 Reply Last reply
                        0
                        • Q qcoderpro

                          @jsulm
                          I mean, is the story this way?
                          When both projects are run, the server will get the IP address (provided by noip.com). The client also has that address (in its code) so it connects to it. Then they can exchanges messages.
                          Right?

                          If so, how about the port number!? Don't we need it?

                          jsulmJ Offline
                          jsulmJ Offline
                          jsulm
                          Lifetime Qt Champion
                          wrote on last edited by
                          #19

                          @qcoderpro said in Extending networking/socket programming functionality of a qml project:

                          The client also has that address (in its code) so it connects to it

                          Do you mean IP address? No, client also has to get the IP first.

                          "If so, how about the port number!?" - port number can be fixed (like 8080 for HTTP).

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

                          Q 1 Reply Last reply
                          1
                          • jsulmJ jsulm

                            @qcoderpro said in Extending networking/socket programming functionality of a qml project:

                            The client also has that address (in its code) so it connects to it

                            Do you mean IP address? No, client also has to get the IP first.

                            "If so, how about the port number!?" - port number can be fixed (like 8080 for HTTP).

                            Q Offline
                            Q Offline
                            qcoderpro
                            wrote on last edited by
                            #20

                            @jsulm
                            OK so both projects need to get the IP address at runtime and since the port is set to 8080 (as you said), they can connect and start exchanging messages. Right?

                            jsulmJ 1 Reply Last reply
                            0
                            • Q qcoderpro

                              @jsulm
                              OK so both projects need to get the IP address at runtime and since the port is set to 8080 (as you said), they can connect and start exchanging messages. Right?

                              jsulmJ Offline
                              jsulmJ Offline
                              jsulm
                              Lifetime Qt Champion
                              wrote on last edited by
                              #21

                              @qcoderpro said in Extending networking/socket programming functionality of a qml project:

                              as you said

                              I did not. It was just an example.
                              "they can connect and start exchanging messages" - if they can get the IP then yes.

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

                              Q 1 Reply Last reply
                              1
                              • jsulmJ jsulm

                                @qcoderpro said in Extending networking/socket programming functionality of a qml project:

                                as you said

                                I did not. It was just an example.
                                "they can connect and start exchanging messages" - if they can get the IP then yes.

                                Q Offline
                                Q Offline
                                qcoderpro
                                wrote on last edited by
                                #22

                                @jsulm

                                OK I visited the page for noip.com and read a number of services they offer, some of them are free, but limited, as expected.
                                Are the steps to get the IP needed for the projects to work, as below, please?

                                1: Create an Account.
                                2: Confirm Your Account.
                                3: Log In to Your Account.
                                4: Add a Host or Domain to Your Account.
                                5: Making Your Host Dynamic.
                                6: Configure Your Router.
                                7: Run Your Services

                                I signed up and then went for adding a hostname but for the domain there're many options, as follows:
                                qweqw.png

                                1. Is what I've done so far right, please?
                                2. What to choose for the domain, please?
                                1 Reply Last reply
                                0
                                • SGaistS Offline
                                  SGaistS Offline
                                  SGaist
                                  Lifetime Qt Champion
                                  wrote on last edited by
                                  #23
                                  1. yes
                                  2. that's up to you.

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

                                  Q 1 Reply Last reply
                                  1
                                  • SGaistS SGaist
                                    1. yes
                                    2. that's up to you.
                                    Q Offline
                                    Q Offline
                                    qcoderpro
                                    wrote on last edited by
                                    #24

                                    @SGaist

                                    1. yes

                                    So I need to go through all those 7 steps. Right?

                                    1. that's up to you.

                                    I've no idea what to choose and for what, ect. since I'm new in networking and my purpose for using noip service ( (for now)) is just to use it for my two QML projects mentioned above. Which domain do you suggest, please?

                                    1 Reply Last reply
                                    0
                                    • SGaistS Offline
                                      SGaistS Offline
                                      SGaist
                                      Lifetime Qt Champion
                                      wrote on last edited by
                                      #25
                                      1. except the router step, that part you will need to do for your device.

                                      2. the subdomain really does not matter that much, hence your choice. The default shall be fine.

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

                                      Q 1 Reply Last reply
                                      1
                                      • SGaistS SGaist
                                        1. except the router step, that part you will need to do for your device.

                                        2. the subdomain really does not matter that much, hence your choice. The default shall be fine.

                                        Q Offline
                                        Q Offline
                                        qcoderpro
                                        wrote on last edited by
                                        #26

                                        @SGaist
                                        I created the hostname with the default domain.
                                        1- But is this hostname the IP address we were aiming to get from noip!?

                                        For the step 5, I installed their app on my Windows and it takes my IP and point it to the hostname so that the hostname works statically as though I'm having a static IP.
                                        But my two apps should not rely on my machine and IP address. They may be run by two different people from different countries.
                                        What I need is that, that hostname acts like a bridge to connect the apps independently of the place they're running from.

                                        1 Reply Last reply
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                                        • SGaistS Offline
                                          SGaistS Offline
                                          SGaist
                                          Lifetime Qt Champion
                                          wrote on last edited by
                                          #27

                                          The device that runs the server shall update the record at noip to point to its own address.

                                          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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