JSON and escaped double quote

Question

I'm currently making a callout to a 3rd party vendor and I'm getting a huge response. What is currently messing me up is this section:

 "MessageSeq":13,"Description":"config file: config-qa1.txt\"","MessageTS":"2014-02-17T14:46:58","MessageLevel":4,"IsSystemMessage":false

As you can see here, the portion at the end of the Description value is ended with backslash double quote. If I attempt to parse this via the JSONParser I get an exception. Does anyone have an recommendations on how to resolve this?

Exception Message:

System.JSONException: Unexpected character ('"' (code 34)): was expecting comma to separate OBJECT entries at [line:1, column:3699]

Updated with sample Code

public class ResponseWrapper{
    // fields from JSON to auto map
    public Integer messageSeq;
    public String Description;
    public String messageTS;
    public Integer messageLevel;
    public Boolean isSystemMessage;
    // parsing fields
    private ResponseWrapper theResponse;
    private JSONParser parser;

    public void parse(String jsonString){
        parser = JSON.createParser(jsonString);
        parseJSON();
    }

    private void parseJSON(){   
        while (parser.nextToken() != null) {
            if (parser.getCurrentToken() == JSONToken.START_OBJECT) {
                theResponse = (ResponseWrapper)parser.readValueAs(ResponseWrapper.class);               
            }
        }
    }
}

String responseString = '{"MessageSeq":13,"Description":"config file: config-qa1.txt\"","MessageTS":"2014-02-17T14:46:58","MessageLevel":4,"IsSystemMessage":false}';
system.debug('\n\nBEFORE\n' + responseString);
****Place code in here to test such as ReplaceALL***
ResponseWrapper parser = new ResponseWrapper();
parser.parse(responseString);

Answer 1

It sounds like your exception is encountered not by the response, but by Apex code mimicking it?

The response format is correct: the backslash \ is correctly placed to permit a " in the JSON.

Check it out, if I put your string, literally, as plaintext into something returnable by an Apex function:

<apex:page contentType="text/plain">{"MessageSeq":13,"Description":"config file: config-qa1.txt\"","MessageTS":"2014-02-17T14:46:58","MessageLevel":4,"IsSystemMessage":false}</apex:page>

And then obtain that string in Apex:

String data = Page.MyTestPage.getContent().toString();
Map<String,Object> obj = (Map<String,Object>)Json.deserializeUntyped(data);
System.debug(obj);

he will deserialize just fine!

But if you intend to recreate that string in Apex source code, say in a test method, as a WebServiceMock or HttpCalloutMock you must escape the backslash itself in Apex:

String data = '{"MessageSeq":13,"Description":"config file: config-qa1.txt\\"","MessageTS":"2014-02-17T14:46:58","MessageLevel":4,"IsSystemMessage":false}';
//see double backslash here_______________________________________________^

Answer 2

If you want to continue using dphil's idea, then '\\\"' (3 slashes) might work in the replace statement. However, your original problem is still odd.

Answer 3

It doesn't look like that belongs there.... Maybe you should just parse it out before using the JSONParser?

jsonString = jsonString.replace('\\"', '');