Class: Jets::Controller::Middleware::Mimic

Inherits:
Object
  • Object
show all
Extended by:
Memoist
Defined in:
lib/jets/controller/middleware/mimic/apigw.rb,
lib/jets/controller/middleware/mimic.rb,
lib/jets/controller/middleware/mimic/lambda_context.rb

Overview

Takes a Rack env and converts to ApiGateway event This runs only locally, when not on AWS Lambda Note: Logic in the opposite direction: Jets::Controller::Handler::Apigw#rack_vars

Defined Under Namespace

Classes: Apigw, LambdaContext

Instance Method Summary collapse

Constructor Details

#initialize(app) ⇒ Mimic

Returns a new instance of Mimic.



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# File 'lib/jets/controller/middleware/mimic.rb', line 9

def initialize(app)
  @app = app
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/jets/controller/middleware/mimic.rb', line 13

def call(env)
  matcher = Jets::Router::Matcher.new
  route = matcher.find_by_env(env) # simpler version does not check constraints
  return not_found(env) unless route

  # Make instance available so we dont not have to pass it around.
  # Also important to assign to instance variables so values are memoized in variables
  # So the mimic logic work because @env.merge! does not happened
  # until end. We do not want apigw.controller to create a new controller instance
  # with a different object_id
  apigw = Apigw.new(route, env) # takes rack env and converts to API Gateway event structure
  @controller = apigw.controller
  @meth = apigw.meth
  @event = apigw.event
  @context = apigw.context

  route = matcher.find_by_request(@controller.request) # need request object to check constraints
  return not_found(env) unless route

  if route.to == 'jets/rack#process' # megamode
    # Bypass the Jets middlewares since it could interfere with the Rack
    # application's middleware stack.
    #
    # Jets sends back a transfer-encoding=chunked. Curling Jets directly works,
    # but passing the Jets response back through this middleware results in errors.
    # Disable chunking responses by deleting the transfer-encoding response header.
    # Would like to understand why this happens this better, if someone can explain please let me know.
    status, headers, body = @controller.dispatch! # jets/rack_controller
    headers.delete "transfer-encoding"
    [status, headers, body]
  elsif route.to == 'jets/mount#call' # mount route
    status, headers, body = @controller.dispatch! # jets/mount_controller
    [status, headers, body]
  elsif polymorphic_function?
    run_polymophic_function
  else # Normal Jets request
    unless on_aws?(env)
      # Only set these variables when running locally and not on AWS.
      # On AWS, these are set by the Jets::Controller::Handler::Apigw#rack_vars
      env.merge!(
        'jets.controller' => @controller, # mimic controller instance
        'jets.context'    => @context,    # mimic context
        'jets.event'      => @event,      # mimic event
        'jets.meth'       => @meth,
      )
    end
    @app.call(env) # goes to all middleware all the way to Jets::Controller::Middleware::Main
  end
end

#not_found(env) ⇒ Object

Raises:



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# File 'lib/jets/controller/middleware/mimic.rb', line 101

def not_found(env)
  raise Jets::Controller::RoutingError, "No route matches #{env['PATH_INFO'].inspect}"
end

#on_aws?(env) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/jets/controller/middleware/mimic.rb', line 84

def on_aws?(env)
  return true if ENV['ON_AWS']
  return false if Jets.env.test? # usually with test we're passing in full API Gateway fixtures with the HTTP_X_AMZN_TRACE_ID
  return false if ENV['JETS_ELB'] # If we're using an ELB and Jets is inside a container running jets server, we don't want to pretend we're on AWS.
  on_cloud9 = !!(env['HTTP_HOST'] =~ /cloud9\..*\.amazonaws\.com/)
  !!env['HTTP_X_AMZN_TRACE_ID'] && !on_cloud9
end

#polymorphic_function ⇒ Object 



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# File 'lib/jets/controller/middleware/mimic.rb', line 69

def polymorphic_function
  # Abusing Poly to run polymorphic code, should call LambdaExecutor directly
  # after reworking LambdaExecutor so it has a better interface.
  Jets::Poly.new(@controller.class, @meth)
end

#polymorphic_function? ⇒ Boolean

Never hit when calling polymorphic function on AWS Lambda. Can only get called with the local server.

Returns:

  • (Boolean) 


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# File 'lib/jets/controller/middleware/mimic.rb', line 64

def polymorphic_function?
  return false if ENV['_HANDLER'] # slight speed improvement on Lambda
  polymorphic_function.definition.lang != :ruby
end

#routes_error_message(env) ⇒ Object 



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# File 'lib/jets/controller/middleware/mimic.rb', line 92

def routes_error_message(env)
  message = "<h2>404 Error: Route #{env['PATH_INFO'].sub('/','')} not found</h2>"
  if Jets.env != "production"
    message << "<p>Here are the routes defined in your application:</p>"
    message << "#{routes_table}"
  end
  message
end

#run_polymophic_function ⇒ Object 



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# File 'lib/jets/controller/middleware/mimic.rb', line 76

def run_polymophic_function
  resp = polymorphic_function.run(@event, @meth) # polymorphic code
  status = resp['statusCode']
  headers = resp['headers']
  body = StringIO.new(resp['body'])
  [status, headers, body] # triplet
end