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About me Andriy Savchenko /ptico CTO Aejis [email protected] 

RubyMeditation 

W A R N I N G THIS TALK CONTAINS LOTS
 OF CODE THIS IS YOUR LAST CHANCE TO LEAVE AUDITORY 

Problems with rails 

• Low latency • Dependency hell • MVC is only suitable for simple CRUD • ActiveSupport 

Other frameworks 

• grape • sinatra • rum • nyny 

And… 

Rack 

run ->(env) { [ 200, # <= Response code {'Content-Type' => 'application/json'}, # <= Headers [ '{"a": 1}' ] # <= Body ] } 

require 'json' run ->(env) { [ 200, {'Content-Type' => 'application/json'}, [ JSON.dump({ a: 1 }) ] # <= Almost API ;) ] } 

Add some OOP 

run ->(env) { [ 200, # <= Response code {'Content-Type' => 'application/json'}, # <= Headers [ '{"a": 1}' ] # <= Body ] } 

class Responder def response_code 200 end def headers {'Content-Type' => 'application/json'} end def body [ JSON.dump({ a: 1 }) ] end end 

class Responder def response_code @code end def headers @headers end def body [ JSON.dump(@body) ] end end 

class Example < Responder def initialize(env) @code = 200 @headers = {'Content-Type' => 'application/json'} @body = { a: 1 } end end 

class ReadUsers < Responder def initialize(env) @code = 200 @headers = {'Content-Type' => 'application/json'} @body = DB[:users].all end end 

run ->(env) { result = ReadUsers.new(env) [result.response_code, result.headers, result.body] } 

result = ReadUsers.new(env) r = Nginx::Request.new result.headers.each_pair { |k, v| r.headers_out[k] = v } Nginx.rputs result.body[0] Nginx.return result.response_code 

Less generic example 

Good API • Proper status codes • Compatibility (?suppress_response_code=true) • Metadata 

class Responder class << self def call(env) req = ::Rack::Request.new(env) instance = new(req) instance.call instance.to_rack_array end end attr_reader :request, :params, :headers def initialize(req) @request = req @params = req.params @headers = default_response_headers end def call; end def to_rack_array [http_response_code, http_response_headers, http_response_body] end end 

class Responder def response_code @response_code || default_response_code end private def default_response_code 200 end def http_response_code params['suppress_response_codes'] ? 200 : response_code end end 

class Responder def default_response_headers { 'Content-Type' => 'application/json' }.dup end def http_response_headers @headers end end 

class Responder def body @body end private def http_response_body [ JSON.dump(body) ] end end 

class ReadUsers < Responder def call @body = DB[:users].all end end 

class Read < Responder def call @body = fetch end end 

class ReadUsers < Read def fetch DB[:users].all end end 

class Write < Responder def call @body = valid_params? ? success : failure end private def success; end def failure; end def valid_params? true end end 

class CreateUser < Write def default_response_code 201 end def valid_params? params['login'] && params['email'] end def success DB[:users].insert(params) end def failure @response_code = 400 { error: 'Invalid params' } end end 

class Responder def body { code: http_response_code, result: @body, meta: meta } end def meta { server_time: Time.now.to_i } end end 

{ "code": 200, "result": [ { "id": 1, "name": "Andriy Savchenko", "email": "[email protected]", "company": "Aejis", "hiring": true } ], "meta": { "server_time": 1447939835 } } 

Awesome! 

Routers • Rack::Builder • http_router (gh:joshbuddy/http_router) • lotus-router (gh:lotus/router) • signpost (gh:Ptico/signpost) • journey (dead) 

Advantages 

Faster $ ruby -v ruby 2.2.3p173 (2015-08-18 revision 51636) [x86_64-darwin15] $ puma -e production $ ab -n 10000 -c 100 http://0.0.0.0:9292/users/ |======================|====Rails-API====|=====Sinatra=====|=====Rack API====| |Time taken for tests: | 13.262 seconds | 6.858 seconds | 3.665 seconds | |Complete requests: | 10000 | 10000 | 10000 | |Failed requests: | 0 | 0 | 0 | |Requests per second: | 754.03 [#/sec] | 1458.20 [#/sec] | 2728.28 [#/sec] | |Time per request: | 132.620 [ms] | 68.578 [ms] | 36.653 [ms] | |Time per request (c): | 1.326 [ms] | 0.686 [ms] | 0.367 [ms] | |Transfer rate: | 301.91 [KB/sec] | 262.02 [KB/sec] | 402.31 [KB/sec] | |============================================================================| 

Faster • 4x faster then rails-api & 2x then sinatra • Ready for further improvements 

Magic-less • Base responder takes ≈ 65LOC • The only dependency is Rack (optional) 

Maintainable • Stable object interface • Each responder can have its own file structure • SOLID • Test-friendly 

Questions? Credits and attributions: • Title illustration by Max Bohdanowski • Lobster Two font by Pablo Impallari & Igino Marini (OFL) • Font Awesome by Dave Gandy - http://fontawesome.io (OFL) • https://www.flickr.com/photos/mattsh/14194586111/ (CC BY-NC-SA 2.0) Andriy Savchenko /ptico [email protected]