Module: Canvas::Embed

Defined in:
lib/canvas/embed.rb,
lib/canvas/embed/version.rb

Constant Summary collapse

VERSION = 
'0.1.8'

Class Method Summary collapse

Class Method Details

.generate_embed_token(private_key, scopes, expiration_seconds = 3600, user_id = nil) ⇒ Object

Public: Generate a token granting access to a scoped set of your data in Canvas

private_key - String, signing key obtained from Canvas scopes - Hash, containing the scopes to grant for this token expiration_seconds - Optional Integer, how long the token should be valid for user_id - Optional String, identifier for the user, used in logging in Canvas.



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# File 'lib/canvas/embed.rb', line 20

def generate_embed_token(private_key, scopes, expiration_seconds = 3600, user_id = nil)
  if !scopes.is_a?(Hash)
    raise InvalidScopeError.new("Invalid scope #{scopes} type #{scopes.class}")
  end
  # token consists of an id and the signing key
  key_id, key = private_key.split('.')
  # transform signing key hex into bytes
  key_bytes = [key].pack('H*')
  secret_box = RbNaCl::SecretBox.new(key_bytes)
  nonce = RbNaCl::Random.random_bytes(secret_box.nonce_bytes)
  exp = Time.now.to_i + expiration_seconds
  message = { 'scopes' => scopes, 'exp' => exp }
  if user_id != nil
    message['userId'] = user_id
  end
  ciphertext = secret_box.encrypt(nonce, message.to_json)
  # transform bytes into hex
  unpacked_message = ciphertext.unpack1('H*')
  unpacked_nonce = nonce.unpack1('H*')
  token = { 'message' => unpacked_message, 'nonce' => unpacked_nonce, 'keyId' => key_id }.to_json
  # strict for no newlines
  Base64.strict_encode64(token)
end

.generate_login_token(private_key, email, expiration_seconds = 600, user_id = nil, first_name = nil, last_name = nil) ⇒ Object

Public: Generate a token allowing one of your users to login to your account or sub-account

private_key - String, signing key obtained from Canvas email - String, the email of the user to login. This should match a user or invite in one of your accounts. expiration_seconds - Optional Integer, how long the token should be valid for. Default to 10 minutes. user_id - Optional String, identifier for the user, used in logging in Canvas. first_name - Optional String, first name of the user last_name - Optional String, last name of the user



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# File 'lib/canvas/embed.rb', line 53

def (private_key, email, expiration_seconds = 600, user_id = nil, first_name = nil, last_name = nil)
  # token consists of an id and the signing key
  key_id, key = private_key.split('.')
  # transform signing key hex into bytes
  key_bytes = [key].pack('H*')
  secret_box = RbNaCl::SecretBox.new(key_bytes)
  nonce = RbNaCl::Random.random_bytes(secret_box.nonce_bytes)
  exp = Time.now.to_i + expiration_seconds
  message = { 'email' => email, 'exp' => exp }
  if user_id != nil
    message['userId'] = user_id
  end
  if first_name != nil
    message['firstName'] = first_name
  end
  if last_name != nil
    message['lastName'] = last_name
  end
  ciphertext = secret_box.encrypt(nonce, message.to_json)
  # transform bytes into hex
  unpacked_message = ciphertext.unpack1('H*')
  unpacked_nonce = nonce.unpack1('H*')
  token = { 'message' => unpacked_message, 'nonce' => unpacked_nonce, 'keyId' => key_id }.to_json
  # strict for no newlines
  Base64.strict_encode64(token)
end