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I am trying to get an access OAuth2 token for Yelp Fusion Api using C# as mentioned in the documentation: https://www.yelp.com/developers/documentation/v3/get_started

However, I am getting the error :

client_id or client_secret not found. Make sure to provide client_id and client_secret in the body with the application application/x-www-form-urlencoded

The following is the code snippet:

<code>
string baseURL = "https://api.yelp.com/oauth2/token";
Dictionary<string, string> query = new Dictionary<string, string>();

query["grant_type"] = "client_credentials";
query["client_id"] = CONSUMER_KEY;
query["client_secret"] = CONSUMER_SECRET;

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(baseURL);
request.Accept = "application/json";
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";

StreamWriter requestWriter = new StreamWriter(request.GetRequestStream());
requestWriter.Write(query.ToString());
requestWriter.Close();

HttpWebResponse response = (HttpWebResponse)request.GetResponse();
var stream = new StreamReader(response.GetResponseStream(), Encoding.UTF8);
Console.WriteLine(stream.ReadToEnd());
</code>
rakshithnrr
  • 53
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1 Answers1

0

As per the Yelp Fusion documentation here you need to make a POST call and parameters should be sent in application/x-www-form-urlencoded format. So the method used above is incorrect.

This should help:

HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create(baseURL);
webRequest.Method = "POST";
webRequest.AllowAutoRedirect = true;
webRequest.Timeout = 20 * 1000;
webRequest.ContentType = "application/x-www-form-urlencoded";
webRequest.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8";
webRequest.UserAgent = "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.99 Safari/537.36";

//write the data to post request
String postData = "client_id=" + CLIENT_ID + "&client_secret=" + CLIENT_SECRET + "&grant_type=client_credentials";
byte[] buffer = Encoding.Default.GetBytes(postData);
if (buffer != null)
{
        webRequest.ContentLength = buffer.Length;
        webRequest.GetRequestStream().Write(buffer, 0, buffer.Length);
}
HttpWebResponse response = (HttpWebResponse)webRequest.GetResponse();
Stream dataStream = response.GetResponseStream();
StreamReader reader = new StreamReader(dataStream);
string strResponse = reader.ReadToEnd();

Please note that the example above will return data in String format. To read the actual values, you will have to serialize the data.

Edit: Since March 1, 2018, the authentication process for yelp fusion API has changed. This is not applicable any more.

Prasoon Srivastava
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