Extending networking/socket programming functionality of a qml project

[qcoderpro]

Can't anyone help me how to work the main issue out, please?
I believe the main issue is how to set the IP address of the server app on the noip website or my hostname to make it possible for the client app to get access to the server app and establish a connection.

[SGaist]

The main issue is that you currently do not understand properly how networking works.

As already written, your device automatically gets an IP address as soon as it is properly connected to a network be it WiFi, 4G/5G etc.

[qcoderpro]

@SGaist

I understand this. Suppose the server app is running on a device with IP: 123.456.789
To give that address to the client app, you suggested noip. OK, I signed up and added a hostname too and posted my last talk with them above. Now the main issue is giving that address to the client app or as you say: updating a record on noip. How to do that? This is my problem.

[SGaist]

The client uses the host name that's all from its side.

You server needs to implement the client part that updates the noip record. Take a look at their client to implement that.

[qcoderpro]

@SGaist

The client uses the host name that's all from its side.

The client connects to the hostname and gets its IP address. The IP of the hostname (I mean the one I added, "..dev.ddns.net") for example, is, 123.456.789, so the client now owns this address. Right?

You server needs to implement the client part that updates the noip record.

Does this mean that the server also needs to connect to the hostname above and gets that IP address!?

Take a look at their client to implement that.

Could you give me the address of that part, please?

[SGaist]

No, the server has the address the client application is interested in. It does not get it from noip. noip is a DNS service that associates a hostname with an IP address, nothing more.

As for writing code, see their documentation about that matter.

[qcoderpro]

@SGaist
Before writing the code, please let me understand the case completely.
The server has an IP address that the client is interested in (for establishing the connection). So how the client can know of that IP address?
The client can connect to hostname at noip and get the address of that hostname. But it's different from the server's IP! The server somehow should deliver its IP to the client for the connection. How is it done?

[SGaist]

The client just uses the hostname. That's all.

[qcoderpro]

@SGaist

1. So to sum it up: The client connects to my hostname which has been updated by the server to show its IP address and since this way the client can see the server's IP address it can connect to it. Right?
2. If the above question is right, is this page the one I should study on how to make the server app update the hostname's record with its IP?

[SGaist]

1. Yes
2. Looks like it yes.

[qcoderpro]

@SGaist

So in my server app there should be a line of code as an HTTP request, like this example (of that page):
http://username:password@dynupdate.no-ip.com/nic/update?hostname=mytest.example.com&myip=192.0.2.25

So if:
my username at noip is: coderdevqt@gmail.com
my password there is: passwordexample
and my hostname there is: coderdev.ddns.net

that HTTP request should be:
coderdevqt@gmail.com:passwordexample@dynupdate.no-ip.com/nic/update?hostname=coderdev.ddns.net
Right?

[SGaist]

Don't you think it would have been faster to just write and test the query ?

Also: https.

[qcoderpro]

@SGaist

I'm not sure how to make an HTTP request using QNetworkAccessManager by a single string. I tired this but neither of the qInfo() prints anything. The program also terminates at once! :|

 QNetworkAccessManager* manager = new QNetworkAccessManager(this);
    const QNetworkRequest request;
    const QByteArray data {"https://coderdevqt@gmail.com:passwordexample@dynupdate.no-ip.com/nic/update?hostname=coderdev.ddns.net"};
    manager->put(request,data);

    connect(manager, &QNetworkAccessManager::finished, [] {
        QNetworkReply* reply = nullptr;
        if(reply->error())
            qInfo() << "ERROR!: " + reply->errorString();
        else
            qInfo() << "Reply got back with no error!";

        reply->deleteLater();
    });

[SGaist]

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

connect(manager, &QNetworkAccessManager::finished, [] {
QNetworkReply* reply = nullptr;
if(reply->error())

[JonB]

@qcoderpro
I would also suggest you do the connect(manager, ...) before manager->put() not afterwards.

[qcoderpro]

@SGaist
What do you mean by copying part of the code I wrote above? I didn't get it. Do you mean those three lines of code are sufficient to make an Http request? Then how about the string!? :|

@JonB
You mean this way?

QNetworkAccessManager* manager = new QNetworkAccessManager(this);
const QNetworkRequest request;
const QByteArray data {"https://coderdevqt@gmail.com:passwordexample@dynupdate.no-ip.com/nic/update?hostname=coderdev.ddns.net"};

connect(manager, &QNetworkAccessManager::finished, [] {
        QNetworkReply* reply = nullptr;
        if(reply->error())
            qInfo() << "ERROR!: " + reply->errorString();
        else
            qInfo() << "Reply got back with no error!";

        reply->deleteLater();
    });

manager->put(request,data);

I'm confused! :(
Furthermore the put function uploads the contents of data to the destination request, while both my data and destination are packed into that data!

[JonB]

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

@JonB
You mean this way?

Yes, I think it's preferable to attach the slot to manager's signal before you call manager->put(). Though @VRonin pointed out it doesn't actually matter in this case, but it's good style anyway.

[VRonin]

Since I've been summoned... how is this not a segfault?

QNetworkReply* reply = nullptr;
if(reply->error())

What you should do is connect the QNetworkReply, not the QNetworkAccessManager.

// the initialisation of these 2 looks wrong but I'll ignore it for now
QNetworkAccessManager* manager = new QNetworkAccessManager(this);
const QNetworkRequest request;
const QByteArray data {"https://coderdevqt@gmail.com:passwordexample@dynupdate.no-ip.com/nic/update?hostname=coderdev.ddns.net"};
QNetworkReply* reply = manager->put(request,data);
connect(reply,&QNetworkReply::finished,this,[reply](){
    if(reply->error())
        qInfo() << "ERROR!: " + reply->errorString();
    else
        qInfo() << "Reply got back with no error!";
});
connect(reply,&QNetworkReply::finished,reply,&QNetworkReply::deleteLater);

[qcoderpro]

@VRonin

That's better, thanks. The project doesn't itself terminate and works but I get this error!

I've used the exact same string as yours, of course with my real info.

[VRonin]

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

I've used the exact same string as yours, of course with my real info.

Yeah, I expected something like that, hence my comment:

the initialisation of these 2 looks wrong but I'll ignore it for now

Your request has no url...
I have no idea how the server you are trying to connect to works so it's hard to tell you exactly what to do. Did you manage to do what you want with the server with another tool (like curl, or a browser-based rest client)?