Using QString in evaluateJavaScript as agrument

[kokilakr]

Hello,

I need to send a string which contains newline to javascript function as an argument.

Example:
QString sampleString = "first line \n second line.";
 
const char *kModifyString="\
function modifyString(str)\
{\
return str;\
}\
modifyString(\"%1\");";
 
webFrame->evaluateJavaScript(QString(kModifyString).arg(sampleString ));

Example:
QString sampleString = "first line \n second line.";

const char *kModifyString="\
function modifyString(str)\
{\
return str;\
}\
modifyString(\"%1\");";

webFrame->evaluateJavaScript(QString(kModifyString).arg(sampleString ));

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But %1 do not take QString with newline.

How can I handle this situation? I need to send sampleString to javascript function as argument.

Thanks,

[borisbn]

I had modified your code a little like this:

QString sampleString = "first \n second";
 
    const char *kModifyString="123 %1 456";
 
    QString s = QString( kModifyString ).arg( sampleString );
    char xx[ 1000 ];
    strcpy( xx, s.toAscii().constData() );

QString sampleString = "first \n second";

    const char *kModifyString="123 %1 456";

    QString s = QString( kModifyString ).arg( sampleString );
    char xx[ 1000 ];
    strcpy( xx, s.toAscii().constData() );

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and here is a result:

you see, that xx[ 10 ] equals 10, that is a new line

[kokilakr]

Hello,
Thanks for snippet. The .arg takes string with newline.
But the evaluateJavaScript needs it to specify as \\n instead of \n. But I am unaware of what all the characters my string can contain.
So I want to escape the newline and similiar characters. Any help regarding this.

[borisbn]

You can escape the string, passing to eval function like this

QString scriptString = QString(kModifyString).arg(sampleString);
scriptString.replace( "\n", "\\n" );
webFrame->evaluateJavaScript( scriptString );

QString scriptString = QString(kModifyString).arg(sampleString);
scriptString.replace( "\n", "\\n" );
webFrame->evaluateJavaScript( scriptString );

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[numbat]

You will also have to do:
\r
\"
\\

[borisbn]

By the way (sorry for using alient thread to ask) is there any C++ libraries, provided standard (un)escape functions?
I needed (right form of need in past? ) it to save/load some not simple strings in ini-file.

[numbat]

QString escapeJavascriptString(const QString & str)
{
    QString out;
    QRegExp rx("(\\r|\\n|\\\\|\")");
    int pos = 0, lastPos = 0;
 
    while ((pos = rx.indexIn(str, pos)) != -1)
    {
        out += str.mid(lastPos, pos - lastPos);
 
        switch (rx.cap(1).at(0).unicode())
        {
        case '\r':
            out += "\\r";
            break;
        case '\n':
            out += "\\n";
            break;
        case '"':
            out += "\\\"";
            break;
        case '\\':
            out += "\\\\";
            break;
        }
        pos++;
        lastPos = pos;
    }
    out += str.mid(lastPos);
    return out;
}

QString escapeJavascriptString(const QString & str)
{
    QString out;
    QRegExp rx("(\\r|\\n|\\\\|\")");
    int pos = 0, lastPos = 0;

    while ((pos = rx.indexIn(str, pos)) != -1)
    {
        out += str.mid(lastPos, pos - lastPos);

        switch (rx.cap(1).at(0).unicode())
        {
        case '\r':
            out += "\\r";
            break;
        case '\n':
            out += "\\n";
            break;
        case '"':
            out += "\\\"";
            break;
        case '\\':
            out += "\\\\";
            break;
        }
        pos++;
        lastPos = pos;
    }
    out += str.mid(lastPos);
    return out;
}

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[kokilakr]

Thanks for everyone.
It worked.
First, I need to escape with \\ and then others.