Visual FoxPro
Ibanity HTTP Signature for XS2A, Isabel Connect, Ponto Connect

Demonstrates how to add a Signature header for Ibanity HTTP requests.
Chilkat Visual FoxPro Downloads

Visual FoxPro
LOCAL lnSuccess
LOCAL loJson
LOCAL lcPayload
LOCAL loDtNow
LOCAL lcCreated
LOCAL loCrypt
LOCAL loSbDigestHdrValue
LOCAL lcRequest_target
LOCAL loSbSigningString
LOCAL lcIdempotencyKey
LOCAL lcSigned_headers_list
LOCAL loPrivKey
LOCAL loRsa
LOCAL lcSigBase64
LOCAL loSbSigHeaderValue

lnSuccess = 0

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

* In order to sign your HTTP requests, you have to add 2 headers to the HTTP request: Digest: the digest of the request payload and Signature: the actual signature of the request. 

* POST /xs2a/customer-access-tokens HTTP/1.1
* Host: api.ibanity.com
* Content-Type: application/json
* Digest: SHA-512=z4PhNX7vuL3xVChQ1m2AB9Yg5AULVxXcg/SpIdNs6c5H0NE8XYXysP+DGNKHfuwvY7kxvUdBeoGlODJ6+SfaPg==
* Ibanity-Idempotency-Key: 61f02718-eeee-46e1-b5eb-e8fd6e799c2d
* Signature: keyId="62f02718-eeee-46e1-b5eb-e8fd6e799c2e",created=1599659223,algorithm="hs2019",headers="(request-target) host digest (created) ibanity-idempotency-key",signature="SjWJWbWN7i0...zsbM="
* 
* {"data":{"type":"customerAccessToken", "attributes":{"applicationCustomerReference":"15874569"}}}

* The payload (body) of the above HTTP request is the JSON.
* Build the JSON above.
* Use this online tool to generate code from sample JSON: 
* Generate Code to Create JSON
loJson = CreateObject('Chilkat.JsonObject')
loJson.UpdateString("data.type","customerAccessToken")
loJson.UpdateString("data.attributes.applicationCustomerReference","15874569")

lcPayload = loJson.Emit()
? "payload = " + lcPayload

* Step 1: Build the (created) virtual header

loDtNow = CreateObject('Chilkat.CkDateTime')
loDtNow.SetFromCurrentSystemTime()
lcCreated = loDtNow.GetAsUnixTimeStr(0)
? "created = " + lcCreated

* Step 2: Build the Digest header
loCrypt = CreateObject('Chilkat.Crypt2')
loCrypt.HashAlgorithm = "sha512"
loCrypt.EncodingMode = "base64"
loCrypt.Charset = "utf-8"

loSbDigestHdrValue = CreateObject('Chilkat.StringBuilder')
loSbDigestHdrValue.Append("SHA-512=")
loSbDigestHdrValue.Append(loCrypt.HashStringENC(loJson.Emit()))

? loSbDigestHdrValue.GetAsString()

* Step 3: Build the (request target) virtual header

* In order to build the signature you will need a virtual header named (request-target) (the parentheses are important). 
* The (request-target) is the string concatenation of the HTTP method (in lowercase) with the path and query parameters.
lcRequest_target = "post /xs2a/customer-access-tokens"

* Step 4: Build the signing string

* The signing string is the concatenation of the signed header names (in lowercase) and values separated by a LF.

* You must always sign the following headers: (request-target), host, (created), digest. 
* If used, you must also sign the authorization header and any ibanity-* headers, such as ibanity-idempotency-key. 

loSbSigningString = CreateObject('Chilkat.StringBuilder')
loSbSigningString.Append("(request-target): ")
loSbSigningString.AppendLine(lcRequest_target,0)
loSbSigningString.Append("host: ")
loSbSigningString.AppendLine("api.ibanity.com",0)
loSbSigningString.Append("digest: ")
loSbSigningString.AppendLine(loSbDigestHdrValue.GetAsString(),0)
loSbSigningString.Append("(created): ")
loSbSigningString.AppendLine(lcCreated,0)
loSbSigningString.Append("ibanity-idempotency-key: ")
lcIdempotencyKey = loCrypt.GenerateUuid()
loSbSigningString.Append(lcIdempotencyKey)

* Step 5: Build the signed headers list

* To allow Ibanity to check the signed headers, you must provide a list of the header names. They should be lowercase and in the same order used to create the signing string. 
lcSigned_headers_list = "(request-target) host digest (created) ibanity-idempotency-key"

* Step 6: Build the Signature header

* This is where the real signing happens. The signature header is a combination of several sub-headers -
* 
*     keyId: the identifier for the application's signature certificate, obtained from the Developer Portal
*     algorithm: the digital signature algorithm used to generate the signature (must be hs2019)
*     headers: The list of HTTP headers created in step 5
*     signature: the Base64-encoded digital signature of the signing string created in step 4.

loPrivKey = CreateObject('Chilkat.PrivateKey')
lnSuccess = loPrivKey.LoadEncryptedPemFile("my_ibanity_signature_private_key.pem","pem_password")
IF (lnSuccess = 0) THEN
    ? loPrivKey.LastErrorText
    RELEASE loJson
    RELEASE loDtNow
    RELEASE loCrypt
    RELEASE loSbDigestHdrValue
    RELEASE loSbSigningString
    RELEASE loPrivKey
    CANCEL
ENDIF

loRsa = CreateObject('Chilkat.Rsa')
loRsa.PssSaltLen = 32
loRsa.EncodingMode = "base64"
* Use the RSASSA-PSS signature algorithm
loRsa.PkcsPadding = 0

lnSuccess = loRsa.UsePrivateKey(loPrivKey)
IF (lnSuccess = 0) THEN
    ? loRsa.LastErrorText
    RELEASE loJson
    RELEASE loDtNow
    RELEASE loCrypt
    RELEASE loSbDigestHdrValue
    RELEASE loSbSigningString
    RELEASE loPrivKey
    RELEASE loRsa
    CANCEL
ENDIF

* Sign the signing string.
lcSigBase64 = loRsa.SignStringENC(loSbSigningString.GetAsString(),"sha-256")
IF (loRsa.LastMethodSuccess = 0) THEN
    ? loRsa.LastErrorText
    RELEASE loJson
    RELEASE loDtNow
    RELEASE loCrypt
    RELEASE loSbDigestHdrValue
    RELEASE loSbSigningString
    RELEASE loPrivKey
    RELEASE loRsa
    CANCEL
ENDIF

* Build the signature header value.
loSbSigHeaderValue = CreateObject('Chilkat.StringBuilder')
loSbSigHeaderValue.Append('keyId="')
* Use your identifier for the application's signature certificate, obtained from the Developer Portal
loSbSigHeaderValue.Append("62f02718-eeee-46e1-b5eb-e8fd6e799c2e")
loSbSigHeaderValue.Append('",created=')
loSbSigHeaderValue.Append(lcCreated)
loSbSigHeaderValue.Append(',algorithm="hs2019",headers="')
loSbSigHeaderValue.Append(lcSigned_headers_list)
loSbSigHeaderValue.Append('",signature="')
loSbSigHeaderValue.Append(lcSigBase64)
loSbSigHeaderValue.Append('"')

? loSbSigHeaderValue.GetAsString()

RELEASE loJson
RELEASE loDtNow
RELEASE loCrypt
RELEASE loSbDigestHdrValue
RELEASE loSbSigningString
RELEASE loPrivKey
RELEASE loRsa
RELEASE loSbSigHeaderValue