connecting to web api using c#

Question

I'm trying to autheniicate using the code below to silverpop although I'm getting a status code of 400 when attempting. Any suggestions as I'm not sure what else to try?! I can see the call going out using Fiddler but I've ran out of ideas. Many thanks

The server is returning the following error message:

Code snippet

        var httpWReq = (HttpWebRequest)WebRequest.Create("https://api5.silverpop.com/oauth/token");
        var postData = string.Format("&grant_type=refresh_token&client_id={0}&client_secret={1}&refresh_token={2}", config.ClientId, config.ClientSecret, config.RefreshToken);

                    // Also try this string but I get the same response
        //var postData = string.Format("?grant_type=refresh_token&client_id={0}&client_secret={1}&refresh_token={2}", config.ClientId, config.ClientSecret, config.RefreshToken);

        var encoding = new ASCIIEncoding();
        var data = encoding.GetBytes(postData);
        httpWReq.Method = "POST";
        httpWReq.ContentType = "x-www-form-urlencoded";
        httpWReq.ContentLength = data.Length;

        using (var stream = httpWReq.GetRequestStream())
        {
            stream.Write(data, 0, data.Length);
        }

        var response = (HttpWebResponse)httpWReq.GetResponse();

        var result = new StreamReader(response.GetResponseStream()).ReadToEnd();

Response from server

The remote server returned an error: (400) Bad Request.

postData section doesn't seems good!! shouldn't it start with ? instead & ? Also try debuging, the value for post data to check whether it contains special character! — huMpty duMpty
– huMpty duMpty, Commented Nov 21, 2013 at 17:32
httpWReq.ContentType = "application/x-www-form-urlencoded";? — walkingTarget
– walkingTarget, Commented Nov 21, 2013 at 17:53

Ben Westmoreland · Accepted Answer · 2013-11-22 16:42:10Z

3

This seems to work:

        var httpWReq = (HttpWebRequest)WebRequest.Create("https://api5.silverpop.com/oauth/token" + string.Format("?grant_type=refresh_token&client_id={0}&client_secret={1}&refresh_token={2}", clientId, clientSecret, refreshToken));
        var postData = "";

        var encoding = new ASCIIEncoding();
        var data = encoding.GetBytes(postData);
        httpWReq.Method = "POST";
        httpWReq.ContentType = "x-www-form-urlencoded";
        httpWReq.ContentLength = data.Length;

        using (var stream = httpWReq.GetRequestStream())
        {
            stream.Write(data, 0, data.Length);
        }

        var response = (HttpWebResponse)httpWReq.GetResponse();

        var result = new StreamReader(response.GetResponseStream()).ReadToEnd();

answered Nov 22, 2013 at 16:42

Ben Westmoreland

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Comments

Davecz · Accepted Answer · 2013-11-21 17:30:52Z

1

try change change from

var postData = string.Format("&grant_type=refresh_token&client_id={0}&client_secret={1}&refresh_token={2}", config.ClientId, config.ClientSecret, config.RefreshToken);

to

var postData = string.Format("?grant_type=refresh_token&client_id={0}&client_secret={1}&refresh_token={2}", config.ClientId, config.ClientSecret, config.RefreshToken);

answered Nov 21, 2013 at 17:30

Davecz

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1 Comment

Will Dean Over a year ago

I wouldn't expect the post data to have anything at the beginning, other than the name of the first value.

Сорен Палмундь · Accepted Answer · 2013-11-22 16:50:30Z

0

This usually indicates that you are contacting the server in the wrong way. Are you perhaps missing a '?' in your post data?

EDIT

Try:

var client = new HttpClient();
var content = new FormUrlEncodedContent(<put content here>);
var response = await client.PostAsync("<your API URL>", content);

edited Nov 22, 2013 at 16:50

answered Nov 21, 2013 at 17:29

Сорен Палмундь

613 bronze badges

1 Comment

James Radford Over a year ago

I've made the changes as suggested by others which is now using the '?' at the beginning of the querystring although I'm still getting the same issue. Any other suggestions please?

Alex Dee · Accepted Answer · 2014-09-26 13:29:15Z

0

If you check the request with Fidler you'll see the parameters in body in both cases (with preceding & and with preceding ? signs).

With & sign:

With ? sign:

The proper thing to do would be to remove the ? or the & signs in front and then the parameter name in body will be grant_type. Code that works:

var postData = string.Format("grant_type=refresh_token&client_id={0}&client_secret={1}&refresh_token={2}",
            config.ClientId, config.ClientSecret, config.RefreshToken);

answered Sep 26, 2014 at 13:29

Alex Dee

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