CODEWITHSUNDEEP
jsonjson.netnancy
RMittelman
RMittelman

Reputation: 317

JSON Response Contains Extra Characters

I created a service to do database lookup and return result as JSON, using Nancy. Here is test code:

using (var dt = new DataTable("MyData"))
{
    dt.Columns.Add("id");
    dt.Columns.Add("password");
    dt.Columns.Add("body", System.Type.GetType("System.String"));
    dt.Columns.Add("balance", System.Type.GetType("System.Double"));
    dt.Rows.Add(uid, pwd, "Some useful content", 33.75);
    dt.Rows.Add(uid, pwd, "More useful content", 128.55);
    if (dotNetDataTable)
        json = JsonConvert.SerializeObject(dt, new Serialization.DataTableConverter());
    else
        json = JsonConvert.SerializeObject(dt);
    json = "{\"status\":\"success\",\"data\":" + json + "}";
    return Response.AsJson(json);
}

Interrupting process just before return, and polling value of json, I get:

"{\"status\":\"success\",\"data\":[{\"id\":\"RMittelman\",\"password\":\"Password\",\"body\":\"Some useful content\",\"balance\":33.75},{\"id\":\"RMittelman\",\"password\":\"Password\",\"body\":\"More useful content\",\"balance\":128.55}]}"

This seems correct in immediate window. When I receive data, and interrupt the process, I get this in the client immediate window:

"\"{\\\"status\\\":\\\"success\\\",\\\"data\\\":[{\\\"id\\\":\\\"RMittelman\\\",\\\"password\\\":\\\"Password\\\",\\\"body\\\":\\\"Some useful content\\\",\\\"balance\\\":33.75},{\\\"id\\\":\\\"RMittelman\\\",\\\"password\\\":\\\"Password\\\",\\\"body\\\":\\\"More useful content\\\",\\\"balance\\\":128.55}]}\""

Which as you can see contains extra leading and trailing quotes, and a bunch of extra backslashes. The JSON will not deserialize. Here is the result shown in client's text box:

json result:
"{\"status\":\"success\",\"data\":
[{\"id\":\"RMittelman\",\"password\":\"Password\",\"body\":\"Some useful content\",\"balance\":33.75},
{\"id\":\"RMittelman\",\"password\":\"Password\",\"body\":\"More useful content\",\"balance\":128.55}]}"

Unexpected JSON token when reading DataTable. Expected StartArray, got String. Path '', line 1, position 240.

If I programmatically remove leading and trailing quotes, and all backslashes, it works fine. Here is the code I use in client to get the data:

string GET(string url)
{
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
    try
    {
        WebResponse response = request.GetResponse();
        using (Stream responseStream = response.GetResponseStream())
        {
            StreamReader reader = new StreamReader(responseStream, Encoding.UTF8);
            string responseText = reader.ReadToEnd();
            isError = false;
            return responseText;
        }
    }
    catch (WebException ex)
    {
        isError = true;
        WebResponse errorResponse = ex.Response;
        if (errorResponse == null)
            return ex.Message;
        using (Stream responseStream = errorResponse.GetResponseStream())
        {
            StreamReader reader = new StreamReader(responseStream, Encoding.GetEncoding("utf-8"));
            String errorText = reader.ReadToEnd();
            return errorText;
        }
        throw;
    }
}

So question is, why does it look ok before sending, but contain all the junk after sending?

Upvotes: 0

Views: 2670

Answers (1)

RMittelman
RMittelman

Reputation: 317

JSON was getting double-encoded. Code was:

json=JsonConvert.SerializeObject(dataTable);

then

return Response.AsJson(json);

Changed it to:

return (Response)json;

and the problem went away. Thanks everybody for your input!

Upvotes: 3

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