read data continuously from QProcess

JonB

@jgxy1123
Having written earlier what you need to try to see whether you can get output from 7zip successfully.

Just a heads up: rather than running an external command (you/end-users need 7z.exe installed, and code only works under Windows) you might consider doing the "zipping" directly in your Qt code. zlib is a library written in C that many people use. See also e.g. https://forum.qt.io/topic/74306/how-to-manage-zip-file.

Though your example passes a directory/folder to zip, this can absolutely be done but does require a lot more work than just zipping one file/stream. See e.g. https://github.com/sebastiandev/zipper.

May not apply to you (you may want simplicity of just running 7z.exe command) but here for others reading this.

mranger90

Here's how I parse the output of 7zip and send it to a progress bar object:

   // 7z a -bso0 -bsp1 <destination> <f1> <f2> <f3>
    auto cmd = m_7ZipCommand + "a -bso0 -bsp1 " + destFile + " " + Folder1+ " " +
               Folder2 + " " +  Folder3;

...
  // connect the QProcess finished signal
    connect(&m_zipProcess, QOverload<int, QProcess::ExitStatus>::of(&QProcess::finished), this,
            &ProjectionExporter::onExportFinished);
...
   // Parse the output reported by 7Zip to report the progress percentage
    connect(&m_zipProcess, &QProcess::readyRead, this, [this]() {
        QString output = m_zipProcess.readAllStandardOutput();
        QRegularExpression percentageMessage("^(\\s*)(\\d+)(%.*)$");
        QRegularExpressionMatch match = percentageMessage.match(output);
        if (match.hasMatch())
        {
            const int percentageExported = match.captured(2).toInt();
            const float percentAsFloat = static_cast<float>(percentageExported) / 100.0f;
            m_exportProgress.complatedFiles =
                static_cast<int>(static_cast<float>(m_filesToBeExported) * percentAsFloat);
            m_exportProgress.progressInPercentage = percentageExported;
            emit exportProgress(m_exportProgress);
        }
    });

jsulm

@mranger90 said in read data continuously from QProcess:

connect(&m_zipProcess, &QProcess::readyRead, this, this {

So, is the slot called?

JonB

@mranger90
Looks much like you said originally. Does it get the output to parse? If not, have you acted on the suggestions to your issue?

It would be "odd" to connect slot &QProcess::readyRead with code which only calls readAllStandardOutput().

mranger90

@jsulm
Yes, this slot gets called regularly. It's how I update a progress bar for the operator.

JonB

@mranger90
So are you saying it is resolved and you get what you want, or do you still have any issue?

mranger90

@JonB
I'm not the one with the issue. I posted some working code to help out.

jsulm

@mranger90 If it is called did you check what "output" is? Maybe your regexp is wrong...

JonB

@mranger90 LOL, I'm sorry :)

jsulm

@mranger90 said in read data continuously from QProcess:

I'm not the one with the issue

Oh, I also did not realise :-D