Rack and Middleware

Introduction to Rack and Middleware for YYC Ruby meetup, Feb 2015.

Transcript

1. & Rack Middleware
2. What is Rack?
3. Rack is both a protocol and a gem
4. Created in 2007 By Christian Neukirchen (for reference, Rails was created in 2004)
5. MyApp Thin Unicorn Puma Passenger WEBrick Internets Rails Sinatra Lotus Server Framework Network Application RACK
6. assert app.respond_to? :call status, headers, body = app.call(env) assert status.to_i >= 100 assert headers.is_a? Hash assert body.respond_to? :each
7. class MyApp def call(env) [200, {}, ['Hello world']] end end
8. Proc.new do |env| [200,{},['Hello world']] end
9. ->(env) { [200,{},['Hello world']] }
10. env and CGI
11. curl localhost:8080/hello/world?foo=bar
12. GATEWAY_INTERFACE: "CGI/1.1" HTTP_ACCEPT: "*/*" HTTP_HOST: "localhost:8080" HTTP_USER_AGENT: "curl/7.37.1" HTTP_VERSION: "HTTP/1.1" PATH_INFO: "/hello/world" QUERY_STRING: "foo=bar" REMOTE_ADDR: "::1" REMOTE_HOST: "localhost" REQUEST_METHOD: "GET" REQUEST_PATH: "/hello/world" REQUEST_URI: "http://localhost:8080/hello/world?foo=bar" SCRIPT_NAME: "" SERVER_NAME: "localhost" SERVER_PORT: "8080" SERVER_PROTOCOL: "HTTP/1.1" SERVER_SOFTWARE: "WEBrick/1.3.1 (Ruby/2.1.3/2014-09-19)"
13. GATEWAY_INTERFACE: "CGI/1.1" HTTP_ACCEPT: "*/*" HTTP_HOST: "localhost:8080" HTTP_USER_AGENT: "curl/7.37.1" HTTP_VERSION: "HTTP/1.1" PATH_INFO: "/hello/world" QUERY_STRING: "foo=bar" REMOTE_ADDR: "::1" REMOTE_HOST: "localhost" REQUEST_METHOD: "GET" REQUEST_PATH: "/hello/world" REQUEST_URI: "http://localhost:8080/hello/world?foo=bar" SCRIPT_NAME: "" SERVER_NAME: "localhost" SERVER_PORT: "8080" SERVER_PROTOCOL: "HTTP/1.1" SERVER_SOFTWARE: "WEBrick/1.3.1 (Ruby/2.1.3/2014-09-19)"
14. GATEWAY_INTERFACE: "CGI/1.1" HTTP_ACCEPT: "*/*" HTTP_HOST: "localhost:8080" HTTP_USER_AGENT: "curl/7.37.1" HTTP_VERSION: "HTTP/1.1" PATH_INFO: "/hello/world" QUERY_STRING: "foo=bar" REMOTE_ADDR: "::1" REMOTE_HOST: "localhost" REQUEST_METHOD: "GET" REQUEST_PATH: "/hello/world" REQUEST_URI: "http://localhost:8080/hello/world?foo=bar" SCRIPT_NAME: "" SERVER_NAME: "localhost" SERVER_PORT: "8080" SERVER_PROTOCOL: "HTTP/1.1" SERVER_SOFTWARE: "WEBrick/1.3.1 (Ruby/2.1.3/2014-09-19)"
15. rack.errors: #<IO:<STDERR>> rack.hijack: #<Proc:0x007f8fab939e90 @lib/rack/handler/webrick.rb:77 (lambda)> rack.hijack?: true rack.hijack_io: nil rack.input: #<StringIO:0x007f8fab938298> rack.multiprocess: false rack.multithread: true rack.run_once: false rack.url_scheme: "http" rack.version: [1, 3]
16. rack.errors: #<IO:<STDERR>> rack.hijack: #<Proc:0x007f8fab939e90 @lib/rack/handler/webrick.rb:77 (lambda)> rack.hijack?: true rack.hijack_io: nil rack.input: #<StringIO:0x007f8fab938298> rack.multiprocess: false rack.multithread: true rack.run_once: false rack.url_scheme: "http" rack.version: [1, 3]
17. rack.errors: #<IO:<STDERR>> rack.hijack: #<Proc:0x007f8fab939e90 @lib/rack/handler/webrick.rb:77 (lambda)> rack.hijack?: true rack.hijack_io: nil rack.input: #<StringIO:0x007f8fab938298> rack.multiprocess: false rack.multithread: true rack.run_once: false rack.url_scheme: "http" rack.version: [1, 3]
18. middleware
19. Handler Middleware Middleware App Internets
20. Handler Middleware Middleware Internets Request Request Request Request Request Internets App
21. Handler Middleware Middleware Request Response Response Response Response Internets App
22. Handler Middleware Internets Request Request Request Request Internets Response Response Response Middleware App
23. qux = ->(env){ [200,{},['Hello world']] } bar = ->(env){ qux.call(env) } foo = ->(env){ bar.call(env) } run foo
24. class Middleware def initialize(app) @app = app end def call(env) @app.call(env) end end
25. class Reverse < Middleware def call(env) status, headers, body = super body.each(&:reverse!) [status, headers, body] end end use Reverse use Reverse run ->(env){ [200,{},['Hello world']] }
26. Rack::Builder and config.ru
27. $ rackup config.ru
28. if config.end_with?('ru') Rack::Builder.new { <config.ru> }.to_app end
29. require_relative 'lib/my_app' use Rack::CommonLogger use Rack::Session::Cookie run MyApp.new
30. map '/admin' do use Authorization::Basic run Admin::App.new end map '/api' do use Authorization::Token run Api::App.new end
31. warmup do |app| client = Rack::MockRequest.new(app) client.get '/cached_resource' end
32. rackup greeter.rb
33. if config.end_with?('rb') require config app_name = File.basename(config, '.rb') app = Object.const_get(app_name.capitalize) run app end
34. class Greeter def self.call(env) params = Rack::Request.new(env).params name = params.fetch('name', 'unknown') [200, {}, ["Greetings, #{name}"]] end end
35. # greeter.rb -> Greeter # my_app.rb -> My_app
36. Request, Response, BodyProxy, and Utils
37. def call(env) request = Rack::Request.new(env) request.request_method? request.post? request.get? request.params['query'] request.update_params['query', 'foobar'] request.ip end
38. def call(env) response = @app.call(env) response = Rack::Response.new(response) response['Etag'] = 'abc123' response.redirect('/faq') response.set_cookie('user_id', 123) response.write 'Hello world' end
39. def call(env) status, headers, body = @app.call body = BodyProxy.new(body) do # Ensure something happens after # body.close is called, eg. DB.connection.close end [status, headers, body] end
40. include Rack::Utils parse_query 'foo=bar&foo=qux' #=> {'foo' => ['bar','qux']} parse_nested_query 'foo[]=bar&foo[]=qux' #=> {'foo' => ['bar','qux']} parse_nested_query 'foo[x]=bar&foo[y]=qux' #=> {'foo' => {'x' => 'bar', 'y' => 'qux'}}
41. include Rack::Utils build_query {foo: ['bar','qux']} #=> 'foo=bar&foo=qux' build_nested_query {foo: ['bar', 'qux']} #=> 'foo[]=bar&foo[]=qux' build_nested_query {foo: {x: 'bar', y: 'qux'}} #=> 'foo[x]=bar&foo[y]=qux'
42. Callbacks Cascade Chunked CommonCookies CommonLogger ConditionalGet Config ContentLength ContentType Context CookieJar Cookies DeflateStream Deflater Deflater Deflect Directory ETag ErrorWrapper Evil ExpectationCascade File ForwardRequest GarbageCollector GzipStream HeaderHash HijackWrapper HostMeta InputWrapper InvalidParameterError JSONP KeySpaceConstrainedParams LighttpdScriptNameFix Lint LintError Lobster Locale Lock Logger MD5 MailExceptions MethodOverride NullLogger ParameterTypeError PostBodyContentTypeParser Printout ProcTitle Profiler Recursive Reloader Request ResponseHeaders RouteExceptions Runtime Sendfile SessionHash rack-contrib https://github.com/rack/rack-contrib
43. Rails
44. use Rack::Sendfile use ActionDispatch::Static use Rack::Lock use ActiveSupport::Cache::Strategy::LocalCache::Middleware use Rack::Runtime use Rack::MethodOverride use ActionDispatch::RequestId use Rails::Rack::Logger use ActionDispatch::ShowExceptions use ActionDispatch::DebugExceptions use ActionDispatch::RemoteIp use ActionDispatch::Reloader use ActionDispatch::Callbacks use ActiveRecord::Migration::CheckPending use ActiveRecord::ConnectionAdapters::ConnectionManagement use ActiveRecord::QueryCache use ActionDispatch::Cookies use ActionDispatch::Session::CookieStore use ActionDispatch::Flash use ActionDispatch::ParamsParser use Rack::Head use Rack::ConditionalGet use Rack::ETag run Rails.application.routes $ rake middleware
45. use Rack::Sendfile use ActionDispatch::Static use Rack::Lock use ActiveSupport::Cache::Strategy::LocalCache::Middleware use Rack::Runtime use Rack::MethodOverride use ActionDispatch::RequestId use Rails::Rack::Logger use ActionDispatch::ShowExceptions use ActionDispatch::DebugExceptions use ActionDispatch::RemoteIp use ActionDispatch::Reloader use ActionDispatch::Callbacks use ActiveRecord::Migration::CheckPending use ActiveRecord::ConnectionAdapters::ConnectionManagement use ActiveRecord::QueryCache use ActionDispatch::Cookies use ActionDispatch::Session::CookieStore use ActionDispatch::Flash use ActionDispatch::ParamsParser use Rack::Head use Rack::ConditionalGet use Rack::ETag run Rails.application.routes $ rake middleware
46. Rails.application.routes #=> ActionDispatch::Routing::RouteSet def initialize @set = Journey::Routes.new @router = Journey::Router.new @set end def call(env) req = ActionDispatch::Request.new(env) @router.serve(req) end
47. module ActionDispatch class Request < Rack::Request def initialize(env) super # ... end end end
48. use Rack::Sendfile use ActionDispatch::Static use Rack::Lock use ActiveSupport::Cache::Strategy::LocalCache::Middleware use Rack::Runtime use Rack::MethodOverride use ActionDispatch::RequestId use Rails::Rack::Logger use ActionDispatch::ShowExceptions use ActionDispatch::DebugExceptions use ActionDispatch::RemoteIp use ActionDispatch::Reloader use ActionDispatch::Callbacks use ActiveRecord::Migration::CheckPending use ActiveRecord::ConnectionAdapters::ConnectionManagement use ActiveRecord::QueryCache use ActionDispatch::Cookies use ActionDispatch::Session::CookieStore use ActionDispatch::Flash use ActionDispatch::ParamsParser use Rack::Head use Rack::ConditionalGet use Rack::ETag run Rails.application.routes $ rake middleware
49. use Rack::Sendfile use ActionDispatch::Static use Rack::Lock use ActiveSupport::Cache::Strategy::LocalCache::Middleware use Rack::Runtime use Rack::MethodOverride use ActionDispatch::RequestId use Rails::Rack::Logger use ActionDispatch::ShowExceptions use ActionDispatch::DebugExceptions use ActionDispatch::RemoteIp use ActionDispatch::Reloader use ActionDispatch::Callbacks use ActiveRecord::Migration::CheckPending use ActiveRecord::ConnectionAdapters::ConnectionManagement use ActiveRecord::QueryCache use ActionDispatch::Cookies use ActionDispatch::Session::CookieStore use ActionDispatch::Flash use ActionDispatch::ParamsParser use Rack::Head use Rack::ConditionalGet use Rack::ETag run Rails.application.routes $ rake middleware
50. use Rack::Sendfile use ActionDispatch::Static use Rack::Lock use ActiveSupport::Cache::Strategy::LocalCache::Middleware use Rack::Runtime use Rack::MethodOverride use ActionDispatch::RequestId use Rails::Rack::Logger use ActionDispatch::ShowExceptions use ActionDispatch::DebugExceptions use ActionDispatch::RemoteIp use ActionDispatch::Reloader use ActionDispatch::Callbacks use ActiveRecord::Migration::CheckPending use ActiveRecord::ConnectionAdapters::ConnectionManagement use ActiveRecord::QueryCache use ActionDispatch::Cookies use ActionDispatch::Session::CookieStore use ActionDispatch::Flash use ActionDispatch::ParamsParser use Rack::Head use Rack::ConditionalGet use Rack::ETag run Rails.application.routes $ rake middleware
51. More details about Rails on Rack: http://guides.rubyonrails.org/rails_on_rack.html
52. rack.hijack
53. env['rack.hijack?'] #=> true/false env['rack.hijack'] #=> .call env['rack.hijack_io'] #=> IO/Socket
54. app = Proc.new do |env| io = env['rack.hijack'].call begin io.write("Status: 200\r\n") io.write("Connection: close\r\n") io.write("Content-Type: text/plain\r\n") io.write("\r\n") 10.times do |i| io.write("Line #{i + 1}!\n") io.flush sleep 0.1 end ensure io.close end end
55. app = Proc.new do |env| io = env['rack.hijack'].call begin io.write("Status: 200\r\n") io.write("Connection: close\r\n") io.write("Content-Type: text/plain\r\n") io.write("\r\n") 10.times do |i| io.write("Line #{i + 1}!\n") io.flush sleep 0.1 end ensure io.close end end
56. app = Proc.new do |env| hijack = ->(io) { 10.times do |n| io.write("Line #{n + 1}\n") io.flush sleep 0.1 end io.close } headers = {'rack.hijack' => hijack} [200, headers, nil] }
57. • Supported by Passenger • Supported by Unicorn (for responses < 30s) • Supported by Puma • WEBrick only supports partial hijacking • Not supported by Thin (maybe?)
58. MyApp Server Internets Framework Server Framework Network Application HIJACK Rack
59. The future of Rack? https://github.com/tenderlove/the_metal https://gist.github.com/raggi/11c3491561802e573a47 https://github.com/Wardrop/Rack-Next
60. Exercise https://github.com/yycruby/middleware_exercise git@github.com:yycruby/middleware_exercise.git