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

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

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

Chilkat Python Downloads install with pip pip3 install chilkat or download... Python Module for Windows, MacOS, Linux, Alpine Linux, Solaris

import sys
import chilkat

# 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
json = chilkat.CkJsonObject()
json.UpdateString("data.type","customerAccessToken")
json.UpdateString("data.attributes.applicationCustomerReference","15874569")

payload = json.emit()
print("payload = " + payload)

# Step 1: Build the (created) virtual header

dtNow = chilkat.CkDateTime()
dtNow.SetFromCurrentSystemTime()
created = dtNow.getAsUnixTimeStr(False)
print("created = " + created)

# Step 2: Build the Digest header
crypt = chilkat.CkCrypt2()
crypt.put_HashAlgorithm("sha512")
crypt.put_EncodingMode("base64")
crypt.put_Charset("utf-8")

sbDigestHdrValue = chilkat.CkStringBuilder()
sbDigestHdrValue.Append("SHA-512=")
sbDigestHdrValue.Append(crypt.hashStringENC(json.emit()))

print(sbDigestHdrValue.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.
request_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. 

sbSigningString = chilkat.CkStringBuilder()
sbSigningString.Append("(request-target): ")
sbSigningString.AppendLine(request_target,False)
sbSigningString.Append("host: ")
sbSigningString.AppendLine("api.ibanity.com",False)
sbSigningString.Append("digest: ")
sbSigningString.AppendLine(sbDigestHdrValue.getAsString(),False)
sbSigningString.Append("(created): ")
sbSigningString.AppendLine(created,False)
sbSigningString.Append("ibanity-idempotency-key: ")
idempotencyKey = crypt.generateUuid()
sbSigningString.Append(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 = "(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 = chilkat.CkPrivateKey()
success = privKey.LoadEncryptedPemFile("my_ibanity_signature_private_key.pem","pem_password")
if (success == False):
    print(privKey.lastErrorText())
    sys.exit()

rsa = chilkat.CkRsa()
rsa.put_PssSaltLen(32)
rsa.put_EncodingMode("base64")
# Use the RSASSA-PSS signature algorithm
rsa.put_OaepPadding(True)

success = rsa.ImportPrivateKeyObj(privKey)
if (success == False):
    print(rsa.lastErrorText())
    sys.exit()

# Sign the signing string.
sigBase64 = rsa.signStringENC(sbSigningString.getAsString(),"sha-256")
if (rsa.get_LastMethodSuccess() == False):
    print(rsa.lastErrorText())
    sys.exit()

# Build the signature header value.
sbSigHeaderValue = chilkat.CkStringBuilder()
sbSigHeaderValue.Append("keyId=\"")
# Use your identifier for the application's signature certificate, obtained from the Developer Portal
sbSigHeaderValue.Append("62f02718-eeee-46e1-b5eb-e8fd6e799c2e")
sbSigHeaderValue.Append("\",created=")
sbSigHeaderValue.Append(created)
sbSigHeaderValue.Append(",algorithm=\"hs2019\",headers=\"")
sbSigHeaderValue.Append(signed_headers_list)
sbSigHeaderValue.Append("\",signature=\"")
sbSigHeaderValue.Append(sigBase64)
sbSigHeaderValue.Append("\"")

print(sbSigHeaderValue.getAsString())