Encoding a QString in JSON - qt

Question

I'm trying to encode a QString into a JSON string, so that I can inject it safely via QWebFrame::evaluateJavaScript(QString("o.text = %1;").arg(???)).
For example, in php using the function json_encode
echo json_encode('HELLO "me"');
The output would be
"HELLO \"me\""
This is the internal representation of the string, within the Json object.
In the same way, using Qt, how can I retrieve the internal representation of a string, as it would be encoded as a value, within a Json formatted string?

Answer 1

It's really not that difficult. Start by building up the structure with QJsonObjects
QJsonObject obj;
obj.insert("tag1", QString("Some text"));
Then use QDocument to get a string in Json format
QJsonDocument doc(obj);
QByteArray data = doc.toJson(QJsonDocument::Compact);
QString jsonString(data);
This will produce a string, in the form of: -
{ "tag1" : "Some Text" }
Separate items into a list, splitting on ':'
QStringList items = jsonString.split(':', QString::SkipEmptyParts);
There should be 2 items in the list, the second being the value section of the Json string
"Some Test"}
Remove the final '}'
QString value = items[1].remove('}');
Of-course, you will need to do error checking and be aware that if you have a ':' or '}' in the original string, then you'll need to check for them first.

Answer 2

Original answer doesn't handle : and } inside of string correctly. A similar approach using array which requires only stripping []:
QString encodeJsonStringLiteral(const QString &value)
{
return QString(
QJsonDocument(
QJsonArray() << value
).toJson(QJsonDocument::Compact)
).mid(1).chopped(1);
}
ab"c'd becomes "ab\"c'd"
Or, if you don't need double quotes around the string, replace with .mid(2).chopped(2)