Visual Basic 6.0

ING Open Banking OAuth2 Client Credentials

See more OAuth2 Examples

Demonstrates how to get an access token for the ING Open Banking APIs using client credentials. Visual Basic 6.0

Dim success As Long
success = 0

' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

Dim cert As New ChilkatCert
success = cert.LoadFromFile("qa_data/certs_and_keys/ING/example_client_tls.cer")
If (success = 0) Then
    Debug.Print cert.LastErrorText
    Exit Sub
End If

Dim bdPrivKey As New ChilkatBinData
success = bdPrivKey.LoadFile("qa_data/certs_and_keys/ING/example_client_tls.key")
If (success = 0) Then
    Debug.Print "Failed to load example_client_tls.key"
    Exit Sub
End If

' The OAuth 2.0 client_id for these certificates is e77d776b-90af-4684-bebc-521e5b2614dd. 
' Please note down this client_id since you will need it in the next steps to call the API.

Dim privKey As New PrivateKey
success = privKey.LoadAnyFormat(bdPrivKey,"")
If (success = 0) Then
    Debug.Print privKey.LastErrorText
    Exit Sub
End If

' Associate the private key with the certificate.
success = cert.SetPrivateKey(privKey)
If (success = 0) Then
    Debug.Print cert.LastErrorText
    Exit Sub
End If

Dim http As New ChilkatHttp

success = http.SetSslClientCert(cert)
If (success = 0) Then
    Debug.Print http.LastErrorText
    Exit Sub
End If

' Calculate the Digest and add the "Digest" header.  Do the equivalent of this:
' payload="grant_type=client_credentials"
' payloadDigest=`echo -n "$payload" | openssl dgst -binary -sha256 | openssl base64`
' digest=SHA-256=$payloadDigest
Dim crypt As New ChilkatCrypt2
crypt.HashAlgorithm = "SHA256"
crypt.EncodingMode = "base64"
Dim payload As String
payload = "grant_type=client_credentials"
Dim payloadDigest As String
payloadDigest = crypt.HashStringENC(payload)

' Calculate the current date/time and add the Date header.  
' reqDate=$(LC_TIME=en_US.UTF-8 date -u "+%a, %d %b %Y %H:%M:%S GMT")  
Dim dt As New CkDateTime
success = dt.SetFromCurrentSystemTime()
' The desire date/time format is the "RFC822" format.
http.SetRequestHeader "Date",dt.GetAsRfc822(0)

' Calculate signature for signing your request
' Duplicate the following code:

' 	httpMethod="post"
' 	reqPath="/oauth2/token"
' 	signingString="(request-target): $httpMethod $reqPath
' 	date: $reqDate
' 	digest: $digest"
' 	signature=`printf "$signingString" | openssl dgst -sha256 -sign "${certPath}example_client_signing.key" -passin "pass:changeit" | openssl base64 -A`

Dim httpMethod As String
httpMethod = "POST"
Dim reqPath As String
reqPath = "/oauth2/token"

Dim sbStringToSign As New ChilkatStringBuilder
success = sbStringToSign.Append("(request-target): ")
success = sbStringToSign.Append(httpMethod)
success = sbStringToSign.ToLowercase()
success = sbStringToSign.Append(" ")
success = sbStringToSign.AppendLine(reqPath,0)

success = sbStringToSign.Append("date: ")
success = sbStringToSign.AppendLine(dt.GetAsRfc822(0),0)

success = sbStringToSign.Append("digest: SHA-256=")
success = sbStringToSign.Append(payloadDigest)

Dim signingPrivKey As New PrivateKey
success = signingPrivKey.LoadPemFile("qa_data/certs_and_keys/ING/example_client_signing.key")
If (success = 0) Then
    Debug.Print signingPrivKey.LastErrorText
    Exit Sub
End If

Dim rsa As New ChilkatRsa
success = rsa.UsePrivateKey(signingPrivKey)
If (success = 0) Then
    Debug.Print rsa.LastErrorText
    Exit Sub
End If

rsa.EncodingMode = "base64"
Dim b64Signature As String
b64Signature = rsa.SignStringENC(sbStringToSign.GetAsString(),"SHA256")

Dim sbAuthHdrVal As New ChilkatStringBuilder
success = sbAuthHdrVal.Append("Signature keyId=""e77d776b-90af-4684-bebc-521e5b2614dd"",")
success = sbAuthHdrVal.Append("algorithm=""rsa-sha256"",")
success = sbAuthHdrVal.Append("headers=""(request-target) date digest"",")
success = sbAuthHdrVal.Append("signature=""")
success = sbAuthHdrVal.Append(b64Signature)
success = sbAuthHdrVal.Append("""")

Dim sbDigestHdrVal As New ChilkatStringBuilder
success = sbDigestHdrVal.Append("SHA-256=")
success = sbDigestHdrVal.Append(payloadDigest)

' Do the following CURL statement:

' 	curl -i -X POST "${httpHost}${reqPath}" \
' 	-H 'Accept: application/json' \
' 	-H 'Content-Type: application/x-www-form-urlencoded' \
' 	-H "Digest: ${digest}" \
' 	-H "Date: ${reqDate}" \
' 	-H "authorization: Signature keyId=\"$keyId\",algorithm=\"rsa-sha256\",headers=\"(request-target) date digest\",signature=\"$signature\"" \
' 	-d "${payload}" \
' 	--cert "${certPath}tlsCert.crt" \
' 	--key "${certPath}tlsCert.key"

Dim req As New ChilkatHttpRequest
req.AddParam "grant_type","client_credentials"
req.AddHeader "Accept","application/json"
req.AddHeader "Date",dt.GetAsRfc822(0)
req.AddHeader "Digest",sbDigestHdrVal.GetAsString()
req.AddHeader "Authorization",sbAuthHdrVal.GetAsString()

req.HttpVerb = "POST"
req.ContentType = "application/x-www-form-urlencoded"

Dim resp As New ChilkatHttpResponse
success = http.HttpReq("https://api.sandbox.ing.com/oauth2/token",req,resp)
If (success = 0) Then
    Debug.Print http.LastErrorText
    Exit Sub
End If

' If successful, the status code = 200
Debug.Print "Response Status Code: " & resp.StatusCode
Debug.Print resp.BodyStr

Dim json As New ChilkatJsonObject
success = json.Load(resp.BodyStr)

json.EmitCompact = 0
Debug.Print json.Emit()

' A successful response contains an access token such as:
' {
'   "access_token": "eyJhbGc ... bxI_SoPOBH9xmoM",
'   "expires_in": 905,
'   "scope": "payment-requests:view payment-requests:create payment-requests:close greetings:view virtual-ledger-accounts:fund-reservation:create virtual-ledger-accounts:fund-reservation:delete virtual-ledger-accounts:balance:view",
'   "token_type": "Bearer",
'   "keys": [
'     {
'       "kty": "RSA",
'       "n": "3l3rdz4...04VPkdV",
'       "e": "AQAB",
'       "use": "sig",
'       "alg": "RS256",
'       "x5t": "3c396700fc8cd709cf9cb5452a22bcde76985851"
'     }
'   ],
'   "client_id": "e77d776b-90af-4684-bebc-521e5b2614dd"
' }

' Use this online tool to generate parsing code from sample JSON: 
' Generate Parsing Code from JSON

Dim kty As String
Dim n As String
Dim e As String
Dim use As String
Dim alg As String
Dim x5t As String

Dim access_token As String
access_token = json.StringOf("access_token")
Dim expires_in As Long
expires_in = json.IntOf("expires_in")
Dim scope As String
scope = json.StringOf("scope")
Dim token_type As String
token_type = json.StringOf("token_type")
Dim client_id As String
client_id = json.StringOf("client_id")
Dim i As Long
i = 0
Dim count_i As Long
count_i = json.SizeOfArray("keys")
Do While i < count_i
    json.I = i
    kty = json.StringOf("keys[i].kty")
    n = json.StringOf("keys[i].n")
    e = json.StringOf("keys[i].e")
    use = json.StringOf("keys[i].use")
    alg = json.StringOf("keys[i].alg")
    x5t = json.StringOf("keys[i].x5t")
    i = i + 1
Loop

' This example will save the JSON containing the access key to a file so that
' a subsequent example can load it and then use the access key for a request, such as to create a payment request.
success = json.WriteFile("qa_data/tokens/ing_access_token.json")