Question

I am using below code to shorten long urls

public static string UrlShorten(string url)
{
    string post = "{\"longUrl\": \"" + url + "\"}";
    string shortUrl = url;
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create("https://www.googleapis.com/urlshortener/v1/url?key=" + ReadConfig("GoogleUrlShortnerApiKey"));
    try
    {
        request.ServicePoint.Expect100Continue = false;
        request.Method = "POST";
        request.ContentLength = post.Length;
        request.ContentType = "application/json";
        request.Headers.Add("Cache-Control", "no-cache");

        using (Stream requestStream = request.GetRequestStream())
        {
            byte[] postBuffer = Encoding.ASCII.GetBytes(post);
            requestStream.Write(postBuffer, 0, postBuffer.Length);
        }

        using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
        {
            using (Stream responseStream = response.GetResponseStream())
            {
                using (StreamReader responseReader = new StreamReader(responseStream))
                {
                    string json = responseReader.ReadToEnd();
                    shortUrl = Regex.Match(json, @"""id"": ?""(?<id>.+)""").Groups["id"].Value;
                }
            }
        }
    }
    catch (Exception ex)
    {
        // if Google's URL Shortner is down...
        Utility.LogSave("UrlShorten", "Google's URL Shortner is down", url, ex.ToString());
        //System.Diagnostics.Debug.WriteLine(ex.Message);
        //System.Diagnostics.Debug.WriteLine(ex.StackTrace);
    }
    return shortUrl;
}

I have created a scheduler to shorten large number of urls. And most of the time of got below exception

System.Net.WebException: The remote server returned an error: (403) Forbidden. at System.Net.HttpWebRequest.GetResponse()

I was thinking that due to Courtesy Limit i was getting this exception so increased Per-User Limit by 100,000.0 requests/second/user but still I’m getting the same exception.

I don’t understand why its happening even i am making hardly 2000 request to the server at a time.

Please advise.

Answer 1

Looking at your question I presume it’s a rate-limit exceeded error. You can retrieve the error response if you modify your code like this:

try
{
  ........
}
catch (WebException exception)
{
   string responseText;

   using(var reader = new StreamReader(exception.Response.GetResponseStream()))
   {
     responseText = reader.ReadToEnd();
   }
}
catch (Exception ex)
{
  ......
}

If it’s a rate limit exceeded error you will find something like this in responseText:

{
 "error": {
  "errors": [
   {
    "domain": "usageLimits",
    "reason": "rateLimitExceeded",
    "message": "Rate Limit Exceeded"
   }
  ],
  "code": 403,
  "message": "Rate Limit Exceeded"
 }
}