Class: AzureCommunicationEmail::HmacAuth

Inherits:
Object
  • Object
show all
Defined in:
lib/azure_communication_email/hmac_auth.rb

Instance Method Summary collapse

Constructor Details

#initialize(endpoint:, access_key:) ⇒ HmacAuth

Returns a new instance of HmacAuth.



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# File 'lib/azure_communication_email/hmac_auth.rb', line 15

def initialize(endpoint:, access_key:)
  @endpoint = endpoint # e.g. "https://my-resource.communication.azure.com"
  @access_key = access_key
end

Instance Method Details

#sign_request(http_method:, path_and_query:, body:) ⇒ Object

body: must be the exact JSON string that will go in request.body



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# File 'lib/azure_communication_email/hmac_auth.rb', line 21

def sign_request(http_method:, path_and_query:, body:)
  uri = URI.join(@endpoint, path_and_query)

  content_bytes = body.encode("utf-8")

  # RFC1123 UTC timestamp
  date = Time.now.utc.httpdate

  # Base64(SHA256(request-body-bytes))
  content_hash = base64_sha256(content_bytes)

  # StringToSign
  host = uri.host.downcase
  string_to_sign = [
    http_method.upcase,
    path_and_query,
    "#{date};#{host};#{content_hash}"
  ].join("\n")

  signature = base64_hmac_sha256(string_to_sign, @access_key)

  authorization_header = "HMAC-SHA256 SignedHeaders=x-ms-date;host;x-ms-content-sha256&Signature=#{signature}"

  {
    "x-ms-date" => date,
    "x-ms-content-sha256" => content_hash,
    "Authorization" => authorization_header,
    "Content-Type" => "application/json"
  }
end