Teller payment example with signature

payment_example.rb

require "net/https"
require "time"
require "base64"
require "uri"
require "securerandom"

# Load your private key
pkey = OpenSSL::PKey::RSA.new File.read("private_key.pem")

# Create new HTTP request
uri = URI.parse "https://api.teller.io/accounts/00000000-0000-0000-0000-000000000000/payments/#{SecureRandom.uuid}"
req = Net::HTTP::Put.new uri.request_uri

# Set the request body with the payment parameters
req.form_data = {bank_code: "00-00-00", account_number: "00000000", amount: "0.01"}

# Instantiate a OpenSSL digest
sha256 = OpenSSL::Digest.new("sha256")

# Set Date header
req["Date"] = Time.now.httpdate

# Set Digest header
base64 = Base64.strict_encode64 sha256.digest(req.body)
req["Digest"] = "SHA-256=#{base64}"

# Set the Authorization header using the user access token from the TAuth redirect
req["Authorization"] = "Bearer XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"

# Set your User-Agent string and any other headers you want to include (optional)
req["Accept"] = "application/json"
req["User-Agent"] = "Super Rad App/0.0.1"

# Create signing string
signing_string =
  req.
    each_header.
    inject(["(request-target): #{req.method.downcase} #{req.path}"]) { |arr, (k,v)| arr << ["#{k.downcase}: #{v}"] }.
    join("\n")

# Create list of headers included in signature
header_list = req.each_key.to_a.join(" ")

# Sign the signing string
signature = pkey.sign(sha256, signing_string)

# Construct and set the final Signature header
req["Signature"] = %Q(keyId="certificate",algorithm="rsa-sha256",headers="#{header_list}",signature="#{Base64.strict_encode64(signature)}")

# Make the request!

http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = true
http.cert = OpenSSL::X509::Certificate.new File.read("certificate.pem")
http.key = pkey
http.verify_mode = OpenSSL::SSL::VERIFY_PEER

response = http.request(req)