How to implement load_root_certificates in the README

[shellfly]

from appstoreserverlibrary.models.Environment import Environment
from appstoreserverlibrary.signed_data_verifier import VerificationException, SignedDataVerifier

root_certificates = load_root_certificates()
enable_online_checks = True
bundle_id = "com.example"
environment = Environment.SANDBOX
signed_data_verifier = SignedDataVerifier(root_certificates, enable_online_checks, environment, bundle_id)

try:    
    signed_notification = "ey.."
    payload = signed_data_verifier.verify_and_decode_notification()
    print(payload)
except VerificationException as e:
    print(e)

In the Verification Usage section, there is a load_root_certificates function, but I don't find the implementation. How should I implement this correctly?

[alexanderjordanbaker]

load_root_certificates is meant to be a stand-in for a function that will load the value of the certificates you download from https://www.apple.com/certificateauthority/ under the Apple Root Certificates section. Because these can be passed different ways, via a file, environment argument, or some other type of loader, the specific implantation is left to the user

[shellfly]

@alexanderjordanbaker Thanks for the reply, there are four root certificates listed on the website, but I don't find any description to describe the difference. Do I need to download all of them or is it sufficient to download just one?

[alexanderjordanbaker]

If you were to decode a cert today you would find the G3 root cert, but we recommend downloading all of them. It does take an array of certs in the constructor.

[shellfly]

@alexanderjordanbaker Okay, it would be better to have this information on the README as well, thanks again for the help.

[pduvall]

For any future readers, here is one possible implementation of load_root_certificates() where the 3 .cer files (https://www.apple.com/certificateauthority/) are loaded from the filesystem:

def load_root_certificates():
    cert_paths = [
        'certs/AppleRootCA-G3.cer',
        'certs/AppleRootCA-G2.cer',
        'certs/AppleIncRootCertificate.cer',
    ]   
    certs = []
    for path in cert_paths:
        file = open(path, 'rb')
        cert = file.read()
        file.close()
        certs.append(cert)

    return certs

This is by no means the only implementation (or even necessarily a 'good' one, what with the hardcoded file paths). But it will enable you to get started with the App Store Server Library in Python.