Authorization error on call to server-to-server CloudKit Web Services

I'm attempting to implement some basic integration with CloudKit web services, following Apple's guide for authenticating requests. I've followed some help from this and this question as to how to properly authorize requests, and seem to be following all steps correctly, but I'm still getting a 401 AUTHENTICATION_FAILED error from Apple.

The endpoint I'm targeting is a POST endpoint for retrieving a record, given a record name.

I've added comments to my code to show the outputs i get at various stages, and I've used an alternative certificate so i'm not providing my genuine private key:

def self.signature(parameters, date, image_id)
    #date: 2016-08-14T14:32:20Z

    #parameters: {"records":[{"recordName":"7DBC4FAD-D18C-476A-89FB-14A515098F34"}]}

    encoded_parameters = Digest::SHA256.base64digest(parameters)

    #encoded_parameters: 6gmJ4AvmJgkNY4SJm6ImOxZaZ07J7cih/tRXI0zkRjQ=

    url_subpath = CloudKit.url_subpath

    #url_subpath: /database/1/iCloud.ProjectDent.TwIM/development/public/records/lookup

    message = date + ':' + encoded_parameters + ':' + url_subpath

    #message: 2016-08-14T14:23:35Z:6gmJ4AvmJgkNY4SJm6ImOxZaZ07J7cih/tRXI0zkRjQ=:/database/1/iCloud.ProjectDent.TwIM/development/public/records/lookup

    private_key = OpenSSL::PKey.read(File.read('altkey.pem'))

    signature = private_key.dsa_sign_asn1(OpenSSL::Digest::SHA256.digest(message))

    #signature: -? WX?xfc???ɔ???,?Ț?Փv?3+Xt!?$R?_Y?×*?,?3??Z-\#?ŭ?Ƿh

    encoded_signature = Base64.strict_encode64(signature)

    #encoded_signature: MEUCIFdYlHhmrxoIY8KW1tT6yZT17bYsP8ia09WTdpEzK1h0AiEA0yRSh39fWYHDlyqJLNgzhr9aLVwj2cWtkse3aA0tGZI=

    return encoded_signature
end

def self.headers(parameters, image_id)
    date = Time.now.utc.iso8601

    signature = self.signature(parameters, date, image_id)

    headers = {
        'X-Apple-CloudKit-Request-KeyID' => CloudKit.key_id,
        'X-Apple-CloudKit-Request-ISO8601Date' => date,
        'X-Apple-CloudKit-Request-SignatureV1' => signature
    }

    #headers (key id masked): {"X-Apple-CloudKit-Request-KeyID"=>"123456", "X-Apple-CloudKit-Request-ISO8601Date"=>"2016-08-14T14:32:20Z", "X-Apple-CloudKit-Request-SignatureV1"=>"MEUCIFdYlHhmrxoIY8KW1tT6yZT17bYsP8ia09WTdpEzK1h0AiEA0yRSh39fWYHDlyqJLNgzhr9aLVwj2cWtkse3aA0tGZI="}

    return headers
end

def self.fetch_image(image_id)
    url = CloudKit.url
    parameters = CloudKit.parameters(image_id).to_json
    headers = CloudKit.headers(parameters, image_id)

    begin
        response = RestClient.post(url, parameters, headers)
        puts 'response'
        puts response.code
        puts response.to_str
    rescue => e
        puts 'rescued: ' + e.to_s
    end
end

The end result is:

rescued: 401 Unauthorized

I'm not sure what I'm doing wrong here - I do seem to be following all steps correctly. Hopefully the logs can help someone understand where this might be going wrong.

Recommended topics

Hot tags