CODEWITHSUNDEEP
vb.nettwitter
K. Weber
K. Weber

Reputation: 2773

OAuth authentication with VB.NET

I'm trying to follow this example to access Twitter Stream API (userstream), so I need to do some modifications and this is my final code:

        'We need to define some details about the request. This includes a unique oauth_nonce parameter which must be generated per request, and a timestamp
        Dim oauth_version As String = "1.0"
        Dim oauth_signature_method As String = "HMAC-SHA1"
        Dim oauth_nonce As String = Convert.ToBase64String(New ASCIIEncoding().GetBytes(DateTime.Now.Ticks.ToString()))
        Dim TimeSpan = DateTime.UtcNow - New DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc)
        Dim oauth_timestamp As Integer = Convert.ToInt64(TimeSpan.TotalSeconds).ToString()

        'The next step is to generate an encrypted oAuth signature which Twitter will use to validate the request.
        'To do this, all of the request data is concatenated into a particular format as follows
        Dim baseFormat = "oauth_consumer_key={0}&oauth_nonce={1}&oauth_signature_method={2}" & _
                         "&oauth_timestamp={3}&oauth_token={4}&oauth_version={5}"

        Dim baseString As String = String.Format(baseFormat, _
                        oauth_consumer_key, _
                        oauth_nonce, _
                        oauth_signature_method, _
                        oauth_timestamp, _
                        oauth_token, _
                        oauth_version)

        'baseString = String.Concat("GET&", Uri.EscapeDataString(stream_url), "&", Uri.EscapeDataString(baseString))
        'baseString = String.Concat(Uri.EscapeDataString(stream_url), "&", Uri.EscapeDataString(baseString))
        baseString = Uri.EscapeDataString(stream_url)

        'Using this base string, we then encrypt the data using a composite of the secret keys and the HMAC-SHA1 algorithm.
        Dim compositeKey As String = String.Concat(Uri.EscapeDataString(oauth_consumer_secret), "&", Uri.EscapeDataString(oauth_token_secret))
        Dim oauth_signature As String

        Dim hasher As HMACSHA1 = New HMACSHA1(ASCIIEncoding.ASCII.GetBytes(compositeKey))
        Using hasher
            oauth_signature = Convert.ToBase64String(hasher.ComputeHash(ASCIIEncoding.ASCII.GetBytes(baseString)))
        End Using

        'The oAuth signature is then used to generate the Authentication header.
        'This requires concatenating the public keys and the token generated above into the following format
        Dim headerFormat As String = "OAuth oauth_nonce=""{0}"", oauth_signature_method=""{1}"", " & _
                                       "oauth_timestamp=""{2}"", oauth_consumer_key=""{3}"", " & _
                                       "oauth_token=""{4}"", oauth_signature=""{5}"", " & _
                                       "oauth_version=""{6}"""
        Dim authHeader As String = String.Format(headerFormat, _
                                                Uri.EscapeDataString(oauth_nonce), _
                                                Uri.EscapeDataString(oauth_signature_method), _
                                                Uri.EscapeDataString(oauth_timestamp), _
                                                Uri.EscapeDataString(oauth_consumer_key), _
                                                Uri.EscapeDataString(oauth_token), _
                                                Uri.EscapeDataString(oauth_signature), _
                                                Uri.EscapeDataString(oauth_version))

        'We are now ready to send the request, which is the easy part.
        'Note, we must also disable the Expect: 100-Continue header using the ServicePointManager.
        'Without this code, .NET sends the header by default, which is not supported by Twitter
        Dim req As WebRequest
        Dim res As HttpWebResponse
        Dim streamReader As StreamReader
        Dim wait As Integer = 250
        Dim jsonRes As String = ""
        Dim encode As Encoding = System.Text.Encoding.GetEncoding("utf-8")

        ServicePointManager.Expect100Continue = False
        req = WebRequest.Create(stream_url)
        req.Headers.Add("Authorization", authHeader)

        res = DirectCast(req.GetResponse(), HttpWebResponse)
        streamReader = New StreamReader(res.GetResponseStream(), encode)
        While True
            jsonRes = streamReader.ReadLine()

            'Success
            wait = 250
        End While

        'Abort is needed or responseStream.Close() will hang
        req.Abort()
        streamReader.Close()
        streamReader = Nothing
        res.Close()
        res = Nothing

In this line: res = DirectCast(req.GetResponse(), HttpWebResponse) I get a 401 - Unauthorized, I guess the problem might be in the line where I prepare the OAuth signature, the original used POST and I will need GET, so I changed it and tried these 3 alternatives:

        'baseString = String.Concat("GET&", Uri.EscapeDataString(stream_url), "&", Uri.EscapeDataString(baseString))
        'baseString = String.Concat(Uri.EscapeDataString(stream_url), "&", Uri.EscapeDataString(baseString))
        baseString = Uri.EscapeDataString(stream_url)

Can you help me getting Twitter OAuth working in VB.NET?

For the moment, Twitterizer is not an option as it only works with Visual Studio 2010, and TwitterVB2.dll only works with REST API, not streaming API, I don't know if there are other third party libraries but at this point I would prefer to solve in my own code (too many unmaintaned and incomplete libraries out there).

Thank you

Upvotes: 2

Views: 7143

Answers (1)

K. Weber
K. Weber

Reputation: 2773

Solved, actually the signature was generating ok so the error was somewhere in the method procesing the request, here is my final code, as I mentioned it is based in this C# one:

    Dim resource_url As String
    resource_url = "https://userstream.twitter.com/2/user.json"

    '==========================
    'OBTENCION DEL TOKEN Y SIGNATURE OAUTH

    Dim oauth_version As String = "1.0"
    Dim oauth_signature_method As String = "HMAC-SHA1"
    Dim oauth_nonce As String = Convert.ToBase64String(New ASCIIEncoding().GetBytes(DateTime.Now.Ticks.ToString()))

    Dim timeSpan As TimeSpan = DateTime.UtcNow - New DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc)
    Dim oauth_timestamp As String = Convert.ToInt64(timeSpan.TotalSeconds).ToString()

    Dim oauth_signature As String = GeneraOAuthSignature(resource_url, _
                                                          oauth_nonce, _
                                                          oauth_signature_method, _
                                                          oauth_timestamp, _
                                                          oauth_version)
    '==========================
    'FORMATEO DEL ENCABEZADO OAUTH
    Dim headerFormat As String = "OAuth oauth_nonce=""{0}"", oauth_signature_method=""{1}"", oauth_timestamp=""{2}"", oauth_consumer_key=""{3}"", oauth_token=""{4}"", oauth_signature=""{5}"", oauth_version=""{6}"""

    Dim authHeader As String = String.Format(headerFormat, Uri.EscapeDataString(oauth_nonce), Uri.EscapeDataString(oauth_signature_method), Uri.EscapeDataString(oauth_timestamp), Uri.EscapeDataString(oauth_consumer_key), _
                Uri.EscapeDataString(oauth_token), Uri.EscapeDataString(oauth_signature), Uri.EscapeDataString(oauth_version))

    '==========================
    'LLAMADA HTTP
    ServicePointManager.Expect100Continue = False

    Dim req As WebRequest
    Dim res As HttpWebResponse
    Dim streamReader As StreamReader
    Dim contenidoRespuesta As String = ""
    Dim encode As Encoding = System.Text.Encoding.GetEncoding("utf-8")

    req = WebRequest.Create(resource_url)
    req.Timeout = -1
    req.Headers.Add("Authorization", authHeader)

    res = DirectCast(req.GetResponse(), HttpWebResponse)

    '==========================
    'PROCESAR RESPUESTA
    streamReader = New StreamReader(res.GetResponseStream(), encode)
    While True
        contenidoRespuesta = streamReader.ReadLine()

    End While

    '==========================
    'CIERRE DE STREAMS Y COMUNICACIONES
    'Abort is needed or streamReader.Close() will hang
    req.Abort()
    streamReader.Close()
    streamReader = Nothing
    res.Close()
    res = Nothing

Where:

Function GeneraOAuthSignature(ByVal stream_url As String, _
                              ByVal oauth_nonce As String, _
                              ByVal oauth_signature_method As String, _
                              ByVal oauth_timestamp As String, _
                              ByVal oauth_version As String) As String
    'The next step is to generate an encrypted oAuth signature which Twitter will use to validate the request.
    'To do this, all of the request data is concatenated into a particular format as follows
    Dim baseFormat = "oauth_consumer_key={0}&oauth_nonce={1}&oauth_signature_method={2}" & _
                     "&oauth_timestamp={3}&oauth_token={4}&oauth_version={5}"

    Dim baseString As String = String.Format(baseFormat, _
                    oauth_consumer_key, _
                    oauth_nonce, _
                    oauth_signature_method, _
                    oauth_timestamp, _
                    oauth_token, _
                    oauth_version)

    baseString = String.Concat("GET&", Uri.EscapeDataString(stream_url), "&", Uri.EscapeDataString(baseString))

    'Using this base string, we then encrypt the data using a composite of the secret keys and the HMAC-SHA1 algorithm.
    Dim compositeKey As String = String.Concat(Uri.EscapeDataString(oauth_consumer_secret), "&", Uri.EscapeDataString(oauth_token_secret))
    Dim oauth_signature As String

    Dim hasher As HMACSHA1 = New HMACSHA1(ASCIIEncoding.ASCII.GetBytes(compositeKey))
    Using hasher
        oauth_signature = Convert.ToBase64String(hasher.ComputeHash(ASCIIEncoding.ASCII.GetBytes(baseString)))
    End Using

    Return oauth_signature
End Function

Upvotes: 3

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