apigatewayv2_rack: serve Rack app from AWS Lambda function via API Gateway V2 (HTTP API) or ALB (ELB v2) lambda target

Apigatewayv2Rack provides a method to convert a AWS Lambda invocation event from API Gateway V2 (HTTP API) or ALB lambda target (ELBv2) to a Rack request environment and a method to convert a Rack response tuple to a corresponding Lambda response object.

This gem also provides support for Lambda function URL as it uses the same schema with API Gateway V2.

Supported deployment and limitation

• Supports Rack 2 and Rack 3 specification
• The following AWS Lambda invocation event schemas:
  • Amazon API Gateway HTTP API payload version 2.0
  • ALB lambda function target
• Multiple field lines are not supported on API Gateway schema except set-cookie header due to API Gateway's limitation
• lambda.multi_value_headers.enabled is recommended to be set for usage with ALB. ^[doc]

Usage

Quick usage

# Gemfile
gem 'apigatewayv2_rack'

# main.rb
require 'apigatewayv2_rack'
Main = Apigatewayv2Rack.handler_from_rack_config_file(File.join(__dir__, 'config.ru'))

And set lambda function handler to main.Main.handle then voila!

Non-quick usage

req = Apigatewayv2Rack::Request.new(event: event, context: context)
status, headers, body = rack_app.call(req.to_h)
resp = Apigatewayv2Rack::Response.new(status: status, headers: headers, body: body, elb: req.elb?, multivalued: req.multivalued?)
p resp.as_json

Full example

See ./Dockerfile.integration and ./integration.

Middlewares

This gem includes several utility middlewares:

• CloudfrontVerify: Verify x-origin-header value to protect unwanted direct access.
• CloudfrontXff: Respect cloudfront-viewer-address as x-forwarded-for value.

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/sorah/apigatewayv2_rack.

License

The gem is available as open source under the terms of the MIT License.