Escaping control characters in ServiceNow

Sometimes when you want to make an API request and you want to send a long string which contains newlines (\n), you might run into issues. Recently I got this error for instance:

Your request contained invalid JSON: Invalid control character at: line 5 column 76 (char 119)

This error is due to the REST endpoint not correctly parsing the newline character. To fix this we can escape the newline character before sending it.

ServiceNow has a built in method for this in the GlideStringUtil class called escapeNonPrintable(). Here is an example of how you can use it:

var longString = 'This is a long string\nwith a newline character';
var escapedString = GlideStringUtil.escapeNonPrintable(longString);;
// Output: This is a long string
// with a newline character;
// Output: This is a long string\nwith a newline character