(Chilkat2-Python) ebay: Add Digital Signature to HTTP Request

See more eBay Examples

Demonstrates how to add a digital signature to an ebay HTTP request.

For more information, see https://developer.ebay.com/develop/guides/digital-signatures-for-apis

Chilkat2 Python Downloads install with pip pip3 install chilkat2 or download... Python Module for Windows, Linux, Alpine Linux, MacOS, Solaris

import sys
import chilkat2

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

# Note: Ebay provides a Key Management API
# See https://developer.ebay.com/api-docs/developer/key-management/overview.html

# The following test keys can be used: 
# 
# Ed25519 
# 
# Private Key:
# 
# -----BEGIN PRIVATE KEY-----
# MC4CAQAwBQYDK2VwBCIEIJ+DYvh6SEqVTm50DFtMDoQikTmiCqirVv9mWG9qfSnF
# -----END PRIVATE KEY-----

strPrivateKey = "MC4CAQAwBQYDK2VwBCIEIJ+DYvh6SEqVTm50DFtMDoQikTmiCqirVv9mWG9qfSnF"

# 
# Public Key:
# 
# -----BEGIN PUBLIC KEY-----
# MCowBQYDK2VwAyEAJrQLj5P/89iXES9+vFgrIy29clF9CC/oPPsw3c5D0bs=
# -----END PUBLIC KEY-----

strPublicKey = "MCowBQYDK2VwAyEAJrQLj5P/89iXES9+vFgrIy29clF9CC/oPPsw3c5D0bs="

# This example assumes you got a JWE for your given private key from the Ebay Key Management REST API.
# This JWE is just for example:
strJwe = "eyJ6aXAiOiJERUYiLCJlbmMiOiJBMjU2R0NNIiwidGFnIjoiSXh2dVRMb0FLS0hlS0Zoa3BxQ05CUSIsImFsZyI6IkEyNTZHQ01LVyIsIml2IjoiaFd3YjNoczk2QzEyOTNucCJ9.2o02pR9SoTF4g_5qRXZm6tF4H52TarilIAKxoVUqjd8.3qaF0KJN-rFHHm_P.AMUAe9PPduew09mANIZ-O_68CCuv6EIx096rm9WyLZnYz5N1WFDQ3jP0RBkbaOtQZHImMSPXIHVaB96RWshLuJsUgCKmTAwkPVCZv3zhLxZVxMXtPUuJ-ppVmPIv0NzznWCOU5Kvb9Xux7ZtnlvLXgwOFEix-BaWNomUAazbsrUCbrp514GIea3butbyxXLNi6R9TJUNh8V2uan-optT1MMyS7eMQnVGL5rYBULk.9K5ucUqAu0DqkkhgubsHHw"

sbBody = chilkat2.StringBuilder()
sbBody.Append("{\"hello\": \"world\"}")

print("Body of request:")
print(sbBody.GetAsString())

# -------------------------------------------------
# Build the signature base string...

sbSigBase = chilkat2.StringBuilder()

sbSigBase.Append("\"content-digest\": sha-256=:")
sbSigBase.Append(sbBody.GetHash("sha256","base64","utf-8"))
sbSigBase.Append(":\n")

sbSigBase.Append("\"x-ebay-signature-key\": ")
sbSigBase.Append(strJwe)
sbSigBase.Append("\n")

sbSigBase.Append("\"@method\": POST\n")

# This is the path part of the URL without query params...
sbSigBase.Append("\"@path\": ")
sbSigBase.Append("/verifysignature")
sbSigBase.Append("\n")

# The is the domain, such as "api.ebay.com" w/ port if the port is something unusual.
# In this example, we're testing against a local docker test server (see the info at https://developer.ebay.com/develop/guides/digital-signatures-for-apis)
# Normally, I think it would just be "api.ebay.com" instead of "localhost:8080".
sbSigBase.Append("\"@authority\": ")
sbSigBase.Append("localhost:8080")
sbSigBase.Append("\n")

sbSigBase.Append("\"@signature-params\": ")

sbSigInput = chilkat2.StringBuilder()
sbSigInput.Append("(\"content-digest\" \"x-ebay-signature-key\" \"@method\" \"@path\" \"@authority\")")
sbSigInput.Append(";created=")

dt = chilkat2.CkDateTime()
dt.SetFromCurrentSystemTime()
unixTimeNow = dt.GetAsUnixTimeStr(False)
sbSigInput.Append(unixTimeNow)

sbSigBase.AppendSb(sbSigInput)

# -------------------------------------------------
# Sign the signature base string using the Ed25519 private key

bdPrivKey = chilkat2.BinData()
bdPrivKey.AppendEncoded(strPrivateKey,"base64")

privKey = chilkat2.PrivateKey()
success = privKey.LoadAnyFormat(bdPrivKey,"")
if (success == False):
    print(privKey.LastErrorText)
    sys.exit()

bdToBeSigned = chilkat2.BinData()
bdToBeSigned.AppendSb(sbSigBase,"utf-8")

eddsa = chilkat2.EdDSA()
sigBase64 = eddsa.SignBdENC(bdToBeSigned,"base64",privKey)
if (eddsa.LastMethodSuccess == False):
    print(eddsa.LastErrorText)
    sys.exit()

print("sigBase64:")
print(sigBase64)

# ----------------------------------------------------------
# Send the JSON POST

http = chilkat2.Http()

http.SetRequestHeader("x-ebay-signature-key",strJwe)

sbContentDigestHdr = chilkat2.StringBuilder()
sbContentDigestHdr.Append("sha-256=:")
sbContentDigestHdr.Append(sbBody.GetHash("sha256","base64","utf-8"))
sbContentDigestHdr.Append(":")
http.SetRequestHeader("Content-Digest",sbContentDigestHdr.GetAsString())

sbSigHdr = chilkat2.StringBuilder()
sbSigHdr.Append("sig1=:")
sbSigHdr.Append(sigBase64)
sbSigHdr.Append(":")
http.SetRequestHeader("Signature",sbSigHdr.GetAsString())

sbSigInput.Prepend("sig1=")
http.SetRequestHeader("Signature-Input",sbSigInput.GetAsString())

# Add this header to make eBay actually check the signature.
http.SetRequestHeader("x-ebay-enforce-signature","true")

# Set the OAuth2 access token to add the "Authorization: Bearer <access_token>" to the header.
http.AuthToken = "your_oauth2_access_token"

# The signature base string constructed above is valid if we send this POST to "http://localhost:8080/verifysignature"
# Normally, you'll send your POST to some api.ebay.com endpoint.
url = "http://localhost:8080/verifysignature"

# resp is a CkHttpResponse
resp = http.PostJson2("http://localhost:8080/verifysignature","application/json",sbBody.GetAsString())
if (http.LastMethodSuccess == False):
    print(http.LastErrorText)
    sys.exit()

print("Response status code: " + str(resp.StatusCode))
print("Response body:")
print(resp.BodyStr)