Reading a file with Qt
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wrote on 28 Jul 2018, 09:55 last edited by
Yes I have this problem because I noticed that if my file size is larger than 65535 bytes, the server does not receive all the information. But how do we solve this problem?
Then if I use Qdatastream this to first write the identifier of my message because the one that says if it is a text message (5), if it is a new connection (3), if it is a disconnect (4) and for the file the identifier value is (7) to tell the server that it is a file. Here the QDATASTREAM allows me to write a screen like this:
*Message size
*Identifier
*Message
So if I don't use a Qdatastream how can I write in my QByteArray?
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Yes I have this problem because I noticed that if my file size is larger than 65535 bytes, the server does not receive all the information. But how do we solve this problem?
Then if I use Qdatastream this to first write the identifier of my message because the one that says if it is a text message (5), if it is a new connection (3), if it is a disconnect (4) and for the file the identifier value is (7) to tell the server that it is a file. Here the QDATASTREAM allows me to write a screen like this:
*Message size
*Identifier
*Message
So if I don't use a Qdatastream how can I write in my QByteArray?
Translated with www.DeepL.com/Translator
Hi @EL-jos,
What do you want to do exactly?
For file transfer, decicated protocols exists, e.g. FTP or HTTP. To me it looks like your are re-inventing the wheel?
Regards
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wrote on 28 Jul 2018, 10:47 last edited by EL-jos
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. -
Please take a look at the examples (again...) how to send large data ... http://doc.qt.io/qt-5/qtnetwork-loopback-example.html
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wrote on 28 Jul 2018, 11:02 last edited by
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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wrote on 28 Jul 2018, 17:31 last edited by
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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Hi,
Are you writing both the client and server parts ?
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wrote on 28 Jul 2018, 19:48 last edited by
Yes, do you want me to mail them?
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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.
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wrote on 2 Aug 2018, 20:50 last edited by
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?
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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.
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wrote on 2 Aug 2018, 21:43 last edited by
Theoretically yes, but in practice this is not the case.
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@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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wrote on 3 Aug 2018, 04:34 last edited by
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
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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
@EL-jos
then use quint64 instead. -
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
@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!
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wrote on 6 Aug 2018, 22:29 last edited by
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)? -
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)?Lifetime Qt Championwrote on 7 Aug 2018, 04:55 last edited by jsulm 8 Jul 2018, 04:56@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 -
wrote on 7 Aug 2018, 22:48 last edited by
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
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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
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