Redirecting the output of QProcess when running a resource file

Question

fairly new to Qt.

I'm using QProcess to run an external shell script and redirecting the output to a textBrowser on my GUI. Code:

In mainwindow.h:

private:
   QProcess *myProcess;

and mainwindow.cpp:

void MainWindow::onButtonPressed(){
   myProcess = new QProcess(this);
   myProcess->connect(myProcess, SIGNAL(readyRead()), this, SLOT(textAppend()));
   myProcess->start("./someScript.sh", arguments);
}

void MainWindow::textAppend(){
   ui->textBrowser->append(myProcess->readAll());
}

This works perfectly to run an external script. My question is how to apply the same process with the script included as a resource file. I've tried simply replacing "./someScript.sh" with the resource version ":/someScript.sh" but it does not seem to work. The resource script runs perfectly, but the console output disappears.

What does it mean "does not seem to work"? Do you get the empty output? I would check the resoure file existence first with `QFile::exists(":/someScript.sh")` — paceholder, Dec 21 '16 at 10:18
The script executes (I can see that it does from other sources), but I get empty output. — Sphics, Dec 21 '16 at 10:24

score 6 · Accepted Answer · answered Oct 01 '17 at 02:33

For this reason, there is something called "QTemporaryFile" class.

Because you need to call a file that already exists in your system - ok!

let's take this example :

using QProcess we need to run a python file from resource

//[1] Get Python File From Resource
QFile RsFile(":/send.py");
//[2] Create a Temporary File
QTemporaryFile *NewTempFile = QTemporaryFile::createNativeFile(RsFile);
//[3] Get The Path of Temporary File
QStringList arg;
arg << NewTempFile->fileName();
//[4] Call Process
QProcess *myProcess = new QProcess(this);
myProcess->start("python", arg);
//[5] When You Finish, remove the temporary file
NewTempFile->remove();

Note : on windows, the Temporary File stored in %TEMP% directory

and for more informations you can visit Qt Documentation - QTemporaryFile Class

Good Luck ♥

High quality response, and the answerer's first post. – M. K. Hunter Oct 01 '17 at 02:39 — M. K. Hunter, Oct 01 '17 at 02:39

score 1 · Answer 2 · answered Dec 21 '16 at 10:24

1

I does not work because when you run myProcess->start(":/someScript.sh", arguments); you ask your system to run :/someScript.sh which does not exist for your system.

A quick solution would be to copy the script to a temporary folder and run it from there.

QFile::copy(":/someScript.sh", pathToTmpFile);
myProcess->start(pathToTmpFile, arguments);

I would also suggest you make use of QTemporaryFile to get a unique temporary file name.

answered Dec 21 '16 at 10:24

Benjamin T

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The script runs, as I can see its results outside of my program. I just don't get the console output that I would when running it externally. – Sphics Dec 21 '16 at 10:28
Check `QProcess:error()` and `QProcess::errorString()`. I've just test on ubuntu with Qt 5.6 and I have: QProcess::FailedToStart and "No such file or directory". Also I have absolutely no sign of the script ever being executed. – Benjamin T Dec 21 '16 at 11:01

Redirecting the output of QProcess when running a resource file

2 Answers2