QProcess - Session and Permission

Hi there. Yhis is my first post and I hope someone can help me.

I'm having a problem with QProcess. I'm trying to execute pg_dump (PostgreSQL backup generator) from my application.

I added the agument list containing information about user, host, etc. and setted the enviroment variables to store the password.

I captured the output and received a message from pg_dump that says:

Code:

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pg_dump: [archiver (db)] connection to database "sgtnewnew" failed: could not translate host name "localhost" to address: Unknown host
pg_dump: *** aborted because of error

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The command line I used was:

Code:

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C:\Arquivos de programas\PostgreSQL\8.2\bin>pg_dump.exe -i -h localhost -p 5432 -U postgres -F c -b -v -f C:\testeBat1.backup sgtnewnew

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I made many tests and it seams that pg_dump.exe has not found it dependencies or something else. I tried to create a .bat file and place it in the postgres/bin folder and then call it using QProcess. I got the same error message. When I ran this .bat file by clicking twice over it, the backup was sucessfully done.

I tried to run it using system(c++ function) and it worked fine. The problem is that I need to capture the output (stdout) and QProcess does it for me.

Dows anyone had any problem like this??

Thans for now

Mário

How do you start the process?
On win the arguments have to be contained within quotes. See the documentation for QProcess::start()

This is my entire code. I seams pg_dump received all my parameters, but something was missed and it returned error. Note that I am using the full path of to pg_dump. Yhis _database objectc gives the all information about the database I want to backup :

Code:

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string host = _database->host().empty() ? "localhost" : _database->host();
int port = _database->portNumber() == 0 ? 5432 : _database->portNumber();
string path = "C:\\Arquivos de programas\\PostgreSQL\\8.2\\bin";
string backupExe = "\"" + path + "\\pg_dump.exe\"";
string fileName = string(fileLineEdit->text().latin1());
string envPassword = "PGPASSWORD=" + _database->password();
 
if(!_process)
{
              _process = new QProcess(0);
	connect(_process, SIGNAL(readyReadStdout()), this, SLOT(readFromStdout()));
	connect(_process, SIGNAL(readyReadStderr()), this, SLOT(readFromStderr()));
}
QDir dir(path.c_str());
_process->setWorkingDirectory(dir);
 
_process->clearArguments();
_process->addArgument(backupExe.c_str());
_process->addArgument("-i");
_process->addArgument("-h");
_process->addArgument(host.c_str());
_process->addArgument("-p");
_process->addArgument(Te2String(port).c_str());
_process->addArgument("-U");
_process->addArgument(_database->user().c_str());
_process->addArgument("-Fc");
_process->addArgument("-b");
_process->addArgument("-v");
_process->addArgument("-f");
_process->addArgument(fileName.c_str());
_process->addArgument(_database->databaseName().c_str());
 
QStringList* strList = new QStringList();
strList->append(envPassword.c_str());	
 
if(!_process->start(strList))
{
	QMessageBox::information(this, "Information", "Error starting process");
}

---

Thanks

--------------------------------------------------------------------------------

Obs: I am using QT 3.2.0

Hello,

Using Qt 4.3... In Windows :P~...

• Copy pg_dump.exe to your release folder
• Copy all dependencies (zlib1.dll, libintl3.dll... ) to the same folder :p

This code work's great for me:

Code:

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void ... :: on_backup_do_BD_triggered()
{
    QString nome_arquivo = QFileDialog::getSaveFileName( this,
                           "Realizar Backup do Banco em...",
                           ".",
                           "Arquivo SQL (*.sql)" );
 
    QProcess pg_dump;
 
    QString nome;
    QStringList parametros;
 
    // Definindo a variavel de ambiente que tera o password
    QStringList var_de_ambiente;
 
    var_de_ambiente << "PGPASSWORD=" + banco->password();
 
    pg_dump.setEnvironment( var_de_ambiente );
 
#ifdef Q_OS_WIN32
    nome = "pg_dump.exe";
 
    int porta = banco->port();
 
    parametros << "-f" << nome_arquivo
               << "-F" << "p"
               << "-U" << banco->userName()
               << "-p" << QString::number( porta == -1 ? 5432 : porta )
               << "-h" << banco->hostName()
               << banco->databaseName();
#endif
 
    pg_dump.start( nome, parametros );
    pg_dump.waitForStarted();
    pg_dump.waitForFinished();
 
    if ( pg_dump.exitCode() )
    {
        QMessageBox erro( this );
 
        erro.setWindowTitle( "Erro de backup" );
        erro.setIconPixmap( QPixmap( ":/48x48/alert.png" ) );
        erro.setText( "Ocorreu um erro ao tentar fazero backup do BD." );
 
        erro.exec();
    }
}

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NOTE: PGPASSWORD sets the password used if the server demands password authentication. Use of this environment variable is not recommended for security reasons (some operating systems allow non-root users to see process environment variables via ps);

Dear All

I use the same way to backup, but the problem I have right not is to gzip the file,

I am using Windows and 4.5.0 I would like to gzip the backup I took.

any body can help me for this?