(PureBasic) Ibanity HTTP Signature for XS2A, Isabel Connect, Ponto Connect

See more Ibanity Examples

Demonstrates how to add a Signature header for Ibanity HTTP requests.

For more information, see https://documentation.ibanity.com/http-signature

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkJsonObject.pb"
IncludeFile "CkDateTime.pb"
IncludeFile "CkPrivateKey.pb"
IncludeFile "CkCrypt2.pb"
IncludeFile "CkStringBuilder.pb"
IncludeFile "CkRsa.pb"

Procedure ChilkatExample()

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

    success.i

    ; 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
    json.i = CkJsonObject::ckCreate()
    If json.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkJsonObject::ckUpdateString(json,"data.type","customerAccessToken")
    CkJsonObject::ckUpdateString(json,"data.attributes.applicationCustomerReference","15874569")

    payload.s = CkJsonObject::ckEmit(json)
    Debug "payload = " + payload

    ; Step 1: Build the (created) virtual header

    dtNow.i = CkDateTime::ckCreate()
    If dtNow.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkDateTime::ckSetFromCurrentSystemTime(dtNow)
    created.s = CkDateTime::ckGetAsUnixTimeStr(dtNow,0)
    Debug "created = " + created

    ; Step 2: Build the Digest header
    crypt.i = CkCrypt2::ckCreate()
    If crypt.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkCrypt2::setCkHashAlgorithm(crypt, "sha512")
    CkCrypt2::setCkEncodingMode(crypt, "base64")
    CkCrypt2::setCkCharset(crypt, "utf-8")

    sbDigestHdrValue.i = CkStringBuilder::ckCreate()
    If sbDigestHdrValue.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkStringBuilder::ckAppend(sbDigestHdrValue,"SHA-512=")
    CkStringBuilder::ckAppend(sbDigestHdrValue,CkCrypt2::ckHashStringENC(crypt,CkJsonObject::ckEmit(json)))

    Debug CkStringBuilder::ckGetAsString(sbDigestHdrValue)

    ; 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.
    request_target.s = "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. 

    sbSigningString.i = CkStringBuilder::ckCreate()
    If sbSigningString.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkStringBuilder::ckAppend(sbSigningString,"(request-target): ")
    CkStringBuilder::ckAppendLine(sbSigningString,request_target,0)
    CkStringBuilder::ckAppend(sbSigningString,"host: ")
    CkStringBuilder::ckAppendLine(sbSigningString,"api.ibanity.com",0)
    CkStringBuilder::ckAppend(sbSigningString,"digest: ")
    CkStringBuilder::ckAppendLine(sbSigningString,CkStringBuilder::ckGetAsString(sbDigestHdrValue),0)
    CkStringBuilder::ckAppend(sbSigningString,"(created): ")
    CkStringBuilder::ckAppendLine(sbSigningString,created,0)
    CkStringBuilder::ckAppend(sbSigningString,"ibanity-idempotency-key: ")
    idempotencyKey.s = CkCrypt2::ckGenerateUuid(crypt)
    CkStringBuilder::ckAppend(sbSigningString,idempotencyKey)

    ; 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. 
    signed_headers_list.s = "(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.

    privKey.i = CkPrivateKey::ckCreate()
    If privKey.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkPrivateKey::ckLoadEncryptedPemFile(privKey,"my_ibanity_signature_private_key.pem","pem_password")
    If success = 0
        Debug CkPrivateKey::ckLastErrorText(privKey)
        CkJsonObject::ckDispose(json)
        CkDateTime::ckDispose(dtNow)
        CkCrypt2::ckDispose(crypt)
        CkStringBuilder::ckDispose(sbDigestHdrValue)
        CkStringBuilder::ckDispose(sbSigningString)
        CkPrivateKey::ckDispose(privKey)
        ProcedureReturn
    EndIf

    rsa.i = CkRsa::ckCreate()
    If rsa.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkRsa::setCkPssSaltLen(rsa, 32)
    CkRsa::setCkEncodingMode(rsa, "base64")
    ; Use the RSASSA-PSS signature algorithm
    CkRsa::setCkOaepPadding(rsa, 1)

    success = CkRsa::ckImportPrivateKeyObj(rsa,privKey)
    If success = 0
        Debug CkRsa::ckLastErrorText(rsa)
        CkJsonObject::ckDispose(json)
        CkDateTime::ckDispose(dtNow)
        CkCrypt2::ckDispose(crypt)
        CkStringBuilder::ckDispose(sbDigestHdrValue)
        CkStringBuilder::ckDispose(sbSigningString)
        CkPrivateKey::ckDispose(privKey)
        CkRsa::ckDispose(rsa)
        ProcedureReturn
    EndIf

    ; Sign the signing string.
    sigBase64.s = CkRsa::ckSignStringENC(rsa,CkStringBuilder::ckGetAsString(sbSigningString),"sha-256")
    If CkRsa::ckLastMethodSuccess(rsa) = 0
        Debug CkRsa::ckLastErrorText(rsa)
        CkJsonObject::ckDispose(json)
        CkDateTime::ckDispose(dtNow)
        CkCrypt2::ckDispose(crypt)
        CkStringBuilder::ckDispose(sbDigestHdrValue)
        CkStringBuilder::ckDispose(sbSigningString)
        CkPrivateKey::ckDispose(privKey)
        CkRsa::ckDispose(rsa)
        ProcedureReturn
    EndIf

    ; Build the signature header value.
    sbSigHeaderValue.i = CkStringBuilder::ckCreate()
    If sbSigHeaderValue.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkStringBuilder::ckAppend(sbSigHeaderValue,"keyId=" + Chr(34))
    ; Use your identifier for the application's signature certificate, obtained from the Developer Portal
    CkStringBuilder::ckAppend(sbSigHeaderValue,"62f02718-eeee-46e1-b5eb-e8fd6e799c2e")
    CkStringBuilder::ckAppend(sbSigHeaderValue,Chr(34) + ",created=")
    CkStringBuilder::ckAppend(sbSigHeaderValue,created)
    CkStringBuilder::ckAppend(sbSigHeaderValue,",algorithm=" + Chr(34) + "hs2019" + Chr(34) + ",headers=" + Chr(34))
    CkStringBuilder::ckAppend(sbSigHeaderValue,signed_headers_list)
    CkStringBuilder::ckAppend(sbSigHeaderValue,Chr(34) + ",signature=" + Chr(34))
    CkStringBuilder::ckAppend(sbSigHeaderValue,sigBase64)
    CkStringBuilder::ckAppend(sbSigHeaderValue,Chr(34))

    Debug CkStringBuilder::ckGetAsString(sbSigHeaderValue)


    CkJsonObject::ckDispose(json)
    CkDateTime::ckDispose(dtNow)
    CkCrypt2::ckDispose(crypt)
    CkStringBuilder::ckDispose(sbDigestHdrValue)
    CkStringBuilder::ckDispose(sbSigningString)
    CkPrivateKey::ckDispose(privKey)
    CkRsa::ckDispose(rsa)
    CkStringBuilder::ckDispose(sbSigHeaderValue)


    ProcedureReturn
EndProcedure