Google OAuth Token error - 400 Bad Request

Question

I'm trying to authenticate my application using OAuth2 and using the 'installed applications' flow (get auth-code and then request token). I'm getting a 400 bad request error when requesting the token on the GetResponse() line. My code is as follows:

Public Sub New()
    Dim tokenRequest As WebRequest = 
         WebRequest.Create("https://accounts.google.com/o/oauth2/token")

    Dim requestString As String = "code=<auth-code>" _
                        & "&client_id=<client_id>" _
                        & "&client_secret=<client_secret>" _
                        & "&redirect_uri=http://localhost" _
                        & "&grant_type=authorization_code"

    byteArray = StrToByteArray(System.Web.HttpUtility.UrlEncode(requestString))

    tokenRequest.Credentials = CredentialCache.DefaultCredentials
    tokenRequest.Method = "POST"
    tokenRequest.ContentLength = byteArray.Length
    tokenRequest.ContentType = "application/x-www-form-urlencoded"
    Dim dataStream As Stream = tokenRequest.GetRequestStream()

    dataStream.Write(byteArray, 0, byteArray.Length)
    dataStream.Close()

    Console.WriteLine("Getting response...")

    'Get response
    Try
        Dim response As WebResponse = tokenRequest.GetResponse()

        Console.WriteLine(CType(response, HttpWebResponse).StatusDescription)

        Dim data As Stream = response.GetResponseStream

        Array.Resize(byteArray, 4096)

        Array.Clear(byteArray, 0, byteArray.Length)

        data.Read(byteArray, 0, byteArray.Length)

        response.Close()

    Catch wex As WebException
       Console.WriteLine("ERROR! : ")
        Console.WriteLine(wex.Message)
        Console.WriteLine(wex.Status)
        Console.WriteLine(wex.Data)
        Console.WriteLine(wex.InnerException.Message)
        Console.WriteLine(wex.HelpLink)
    End Try
End Sub

The specifics of the error are below:

The remote server returned an error: (400) Bad Request.
7
System.Collections.ListDictionaryInternal
System.NullReferenceException: Object reference not set to an instance of an obj
ect.
   at GADownload.GoogleAnalytics..ctor() in ***.vb:line 86
   at GADownload.Main1.Main(String[] args) in ****.vb:line 18

I've had a look at Google GetAccessToken : Bad Request 400 and Google GData .Net OAuthUtil.GetAccessToken 400 Bad Request but have not found a solution suited to this code. I have already checked all the solutions suggested and implemented them, but with no luck so far.

Oren Bochman · Answer 1 · 2015-08-14T16:53:30.297

0

looks like you are not setting values for the parameters auth-code, client_id or client_secret.

you can debug these parameters with a curl command to see if this is the source of the problem. e.g.

curl -X POST -d "code=<auth-code>&client_id=<client_id>&client_secret=<client_secret>"&grant_type=authorization_code" http://localhost:8000/auth/token

edited Aug 14 '15 at 16:53

answered Aug 14 '15 at 08:39

Oren Bochman

1,173
3
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37

score 0 · Answer 2 · answered Oct 17 '17 at 15:35

Can you try URL encoding redirect_uri redirect_uri=http://localhost

That is the only thing I'm seeing on your code vs. mine. Here's my code that is similar in vb and working

Dim sb As New StringBuilder
sb.Append("code=").Append(Request.QueryString("code")) _
.Append("&client_id=") _
.Append(Session.Item("ClientID")) _
.Append("&client_secret=") _
.Append(Session.Item("ClientSecret")) _
.Append("&redirect_uri=") _
.Append(HttpUtility.UrlEncode("http://localhost/1.aspx")) _
.Append("&grant_type=authorization_code")
Dim requestGoogle As HttpWebRequest =
WebRequest.Create("https://accounts.google.com/o/oauth2/token")
requestGoogle.Method = "POST"
requestGoogle.ContentType = "application/x-www-form-urlencoded"
requestGoogle.ContentLength = sb.Length
Dim byteArray As Byte() = Encoding.UTF8.GetBytes(sb.ToString)
sb.Clear()
requestGoogle.GetRequestStream.Write(byteArray, 0, byteArray.Length)
byteArray = Nothing
Dim responseGoogle As HttpWebResponse = requestGoogle.GetResponse()
If responseGoogle.StatusCode = HttpStatusCode.OK Then
    Dim sr As StreamReader = _
    New StreamReader(responseGoogle.GetResponseStream)
    Dim s As String = sr.ReadToEnd
    sr.Close()
    responseGoogle.GetResponseStream.Close()
    requestGoogle.GetRequestStream.Close()
    'Response.Write(s)
End If

Google OAuth Token error - 400 Bad Request

2 Answers2