How can I make that a string used to create a custom exception in ASP.NET Web API be interpreted as HttpURLConnection.getResponseMessage () in Android

Question

I'm trying to send custom exceptions from ASP.NET Web API , but when I consume these WebService from Android I'm always getting a different message:

This how I read the webservice in Android:

public Object doRequest(String url) {       
    String charset = Charset.defaultCharset().displayName();
    try {
        if (mFormBody != null) {
            // Form data to post
            mConnection
                    .setRequestProperty("Content-Type",
                            "application/json; charset="
                                    + charset);
            mConnection.setFixedLengthStreamingMode(mFormBody.length());
        }           
        mConnection.connect();

        if (mFormBody != null) {
            OutputStream out = mConnection.getOutputStream();
            writeFormData(charset, out);
        }

        // Get response data
        int status = mConnection.getResponseCode();
        if (status >= 300) {
            String message = mConnection.getResponseMessage();
            return new HttpResponseException(status, message);
        }

        InputStream in = mConnection.getInputStream();
        String enconding = mConnection.getContentEncoding();            
        if (enconding == null) {
            enconding = "UTF-8";
        }
        BufferedReader reader = new BufferedReader(new InputStreamReader(
                in, enconding));

        StringBuilder sb = new StringBuilder();         

        String line=null;           
        while ((line=reader.readLine()) != null) {
              sb.append(line);              
        }

        return sb.toString().trim();

    } catch (Exception e) {
        return e;
    }
    finally{
        if(mConnection!=null){
            mConnection.disconnect();
        }
    }
}

As you can see, I check the value returned by getResponseCode() and if it's equal or greater than 300 I throw an Exception. Everything works except for the fact that getResponseMessage() doesn't return the string I used when I created the exception in WebApi. Instead I get this error:

From WebApi,all I'm doing in the catch block is to throw the exception:

    try
    {

    }
    catch (Exception ex)
    {
        throw ex;
    } 

Using fiddler realized I was getting this message:

{"Message":"Error."}

Well, looking for a solution on Internet, I found that I could do something like this:

try
        {

        }
        catch (Exception ex)
        {   

            throw new HttpResponseException(Request.CreateErrorResponse(HttpStatusCode.NotFound, ex.Message));
            //throw (ex);
        }

But unfortunately this didn't work either. Although fiddler now shows the message I used to create the Exception.

When I read the value of getResponseMessage() is returns this string : "Not Found".

Do you know what I need to do so that the message that is being sent from WebApi through the Exception make its way to Android, specifically to the getResponseMessage() property?

Thanks in advance.

Answer 1

Well, I think you need to create a HttpResponseMessage object first, and based on that object create the HttpResponseException that you're going to throw.

Setting a HttpResponseMessage object is pretty easy. Most of the time you only need to set two properties: Content and ReasonPhrase.

            try
            {

            }
            catch (Exception ex)
            {              

                HttpResponseMessage msg = new HttpResponseMessage(HttpStatusCode.NotFound)
                {
                    Content = new StringContent(string.Format("Excepción")),
                    ReasonPhrase = ex.Message
                };
                throw new HttpResponseException(msg);
            }

As you can see is ReasonPhrase where we passed the exception message.

Hope it helps.