(PowerShell) ING Open Banking OAuth2 Client Credentials

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

For more information, see https://developer.ing.com/openbanking/get-started/openbanking

Chilkat .NET Downloads Chilkat .NET Assemblies

Add-Type -Path "C:\chilkat\ChilkatDotNet47-x64\ChilkatDotNet47.dll"

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

$cert = New-Object Chilkat.Cert
$success = $cert.LoadFromFile("qa_data/certs_and_keys/ING/example_client_tls.cer")
if ($success -eq $false) {
    $($cert.LastErrorText)
    exit
}

$bdPrivKey = New-Object Chilkat.BinData
$success = $bdPrivKey.LoadFile("qa_data/certs_and_keys/ING/example_client_tls.key")
if ($success -eq $false) {
    $("Failed to load example_client_tls.key")
    exit
}

# 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.

$privKey = New-Object Chilkat.PrivateKey
$success = $privKey.LoadAnyFormat($bdPrivKey,"")
if ($success -eq $false) {
    $($privKey.LastErrorText)
    exit
}

# Associate the private key with the certificate.
$success = $cert.SetPrivateKey($privKey)
if ($success -eq $false) {
    $($cert.LastErrorText)
    exit
}

$http = New-Object Chilkat.Http

$success = $http.SetSslClientCert($cert)
if ($success -eq $false) {
    $($http.LastErrorText)
    exit
}

# 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
$crypt = New-Object Chilkat.Crypt2
$crypt.HashAlgorithm = "SHA256"
$crypt.EncodingMode = "base64"
$payload = "grant_type=client_credentials"
$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")  
$dt = New-Object Chilkat.CkDateTime
$dt.SetFromCurrentSystemTime()
# The desire date/time format is the "RFC822" format.
$http.SetRequestHeader("Date",$dt.GetAsRfc822($false))

# 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`

$httpMethod = "POST"
$reqPath = "/oauth2/token"

$sbStringToSign = New-Object Chilkat.StringBuilder
$sbStringToSign.Append("(request-target): ")
$sbStringToSign.Append($httpMethod)
$sbStringToSign.ToLowercase()
$sbStringToSign.Append(" ")
$sbStringToSign.AppendLine($reqPath,$false)

$sbStringToSign.Append("date: ")
$sbStringToSign.AppendLine($dt.GetAsRfc822($false),$false)

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

$signingPrivKey = New-Object Chilkat.PrivateKey
$success = $signingPrivKey.LoadPemFile("qa_data/certs_and_keys/ING/example_client_signing.key")
if ($success -eq $false) {
    $($signingPrivKey.LastErrorText)
    exit
}

$rsa = New-Object Chilkat.Rsa
$success = $rsa.ImportPrivateKeyObj($signingPrivKey)
if ($success -eq $false) {
    $($rsa.LastErrorText)
    exit
}

$rsa.EncodingMode = "base64"
$b64Signature = $rsa.SignStringENC($sbStringToSign.GetAsString(),"SHA256")

$sbAuthHdrVal = New-Object Chilkat.StringBuilder
$sbAuthHdrVal.Append("Signature keyId=`"e77d776b-90af-4684-bebc-521e5b2614dd`",")
$sbAuthHdrVal.Append("algorithm=`"rsa-sha256`",")
$sbAuthHdrVal.Append("headers=`"(request-target) date digest`",")
$sbAuthHdrVal.Append("signature=`"")
$sbAuthHdrVal.Append($b64Signature)
$sbAuthHdrVal.Append("`"")

$sbDigestHdrVal = New-Object Chilkat.StringBuilder
$sbDigestHdrVal.Append("SHA-256=")
$sbDigestHdrVal.Append($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"

$req = New-Object Chilkat.HttpRequest
$req.AddParam("grant_type","client_credentials")
$req.AddHeader("Accept","application/json")
$req.AddHeader("Date",$dt.GetAsRfc822($false))
$req.AddHeader("Digest",$sbDigestHdrVal.GetAsString())
$req.AddHeader("Authorization",$sbAuthHdrVal.GetAsString())
$resp = $http.PostUrlEncoded("https://api.sandbox.ing.com/oauth2/token",$req)
if ($http.LastMethodSuccess -eq $false) {
    $($http.LastErrorText)
    exit
}

# If successful, the status code = 200
$("Response Status Code: " + $resp.StatusCode)
$($resp.BodyStr)

$json = New-Object Chilkat.JsonObject
$json.Load($resp.BodyStr)

$json.EmitCompact = $false
$($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

$access_token = $json.StringOf("access_token")
$expires_in = $json.IntOf("expires_in")
$scope = $json.StringOf("scope")
$token_type = $json.StringOf("token_type")
$client_id = $json.StringOf("client_id")
$i = 0
$count_i = $json.SizeOfArray("keys")
while ($i -lt $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
}

# 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.
$json.WriteFile("qa_data/tokens/ing_access_token.json")