Class: Rack::Firebase::Middleware

Inherits:
Object
  • Object
show all
Defined in:
lib/rack/firebase/middleware.rb

Constant Summary collapse

ALG = 
"RS256".freeze
CERTIFICATE_URL = 
"https://www.googleapis.com/robot/v1/metadata/x509/[email protected]".freeze
USER_UID = 
"firebase.user.uid"

Instance Method Summary collapse

Constructor Details

#initialize(app) ⇒ Middleware

Returns a new instance of Middleware.



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# File 'lib/rack/firebase/middleware.rb', line 11

def initialize(app)
  @app = app

  @config = ::Rack::Firebase.configuration

  @jwt_loader = FIREBASE_KEY_LOADER
  @error_responder = DEFAULT_ERROR_RESPONDER
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/rack/firebase/middleware.rb', line 20

def call(env)
  token = AuthorizationHeader.read_token(env)
  decoded_token, _ = JWT.decode(
    token, nil, true,
    {
      jwks: jwt_loader,
      algorithm: ALG,
      verify_iat: true,
      verify_aud: true, aud: config.project_ids,
      verify_iss: true, iss: firebase_issuers
    }
  )

  raise Rack::Firebase::InvalidSubError.new("Invalid subject") if decoded_token["sub"].nil? || decoded_token["sub"] == ""
  raise Rack::Firebase::InvalidAuthTimeError.new("Invalid auth time") unless decoded_token["auth_time"] <= Time.now.to_i

  env[USER_UID] = decoded_token["sub"]
  @app.call(env)
rescue JWT::JWKError => error # Issues with fetched JWKs
  error_responder.call(error, "unauthorized")
rescue JWT::ExpiredSignature => error # Token has expired
  error_responder.call(error, "expired")
rescue JWT::InvalidIatError => error # invalid issued at claim (iat)
  error_responder.call(error, "unauthorized")
rescue JWT::InvalidIssuerError => error # invalid issuer
  error_responder.call(error, "unauthorized")
rescue JWT::InvalidAudError => error # invalid audience
  error_responder.call(error, "unauthorized")
rescue JWT::DecodeError => error # General JWT error
  error_responder.call(error, "unauthorized")
rescue Rack::Firebase::InvalidSubError => error # subject is empty or missing
  error_responder.call(error, "unauthorized")
rescue Rack::Firebase::InvalidAuthTimeError => error # auth time is in the future
  error_responder.call(error, "unauthorized")
end