functional web apps with webmachine framework - mikhail bortnyk

Ruby Meditation #13

Functional web apps with Webmachine framework

Mikhail Bortnyk, Amoniac OÜ

Who am I❖ Mikhail Bortnyk


❖ github: @vessi


❖ github: @vessi

❖ twitter: @mikhailbortnyk


❖ github: @vessi


❖ language researcher


❖ github: @vessi



❖ co-founder of Kottans community school


❖ github: @vessi




❖ 3rd contributor of mruby/c


❖ github: @vessi




❖ 3rd contributor of mruby/c

❖ Ruby developer (not Rails!)

Source code❖ [Link to presentation online]

Source code❖ [Link to presentation online]

❖ [Link to source code on GitHub]

Introduction

Typical experience of web developer

CGI Old school is cool! (Bash, C, Perl, some scripting)



Servlets I know your pain, bro (PHP, Java)



Servlets I know your pain, bro (PHP, Java)

MVC The thing we all know (Python/Django, Ruby/Rails etc)

SPA is a new sexy❖ No one uses ol’ goo’ ERB

SPA is a new sexy❖ No one uses ol’ goo’ ERB❖ Javascript rules over the web

SPA is a new sexy❖ No one uses ol’ goo’ ERB❖ Javascript rules over the web❖ Web does not work without JS

SPA is a new sexy❖ No one uses ol’ goo’ ERB❖ Javascript rules over the web❖ Web does not work without JS❖ http://tobyho.com/

2010/03/11/how-much-of-the-web-actually/

http://tobyho.com/2010/03/11/how-much-of-the-web-actually/



SPA is a new sexy❖ No one uses ol’ goo’ ERB❖ Javascript rules over the web❖ Web does not work without JS❖ http://tobyho.com/

2010/03/11/how-much-of-the-web-actually/

❖ In fact, you are limited to StackOverflow, Amazon and Google Search




SPA is a new sexy❖ No one uses ol’ goo’ ERB

❖ Javascript rules over the web

❖ Web does not work without JS

❖ http://tobyho.com/2010/03/11/how-much-of-the-web-actually/

❖ In fact, you are limited to StackOverflow, Amazon and Google Search

❖ Actually, only paranoids disable JS in 2017



We are outdated

No more MPA applications

Web developers are developing APIs

APIs for SPAs, for mobile applications, for another APIs

Solutions for APIs❖ Still Rails. Now with API flavor (rails-api)

Solutions for APIs❖ Still Rails. Now with API flavor (rails-api). Still Rails.

Still boring. Still overbloated.



❖ Sinatra is a new shiny



❖ Sinatra is a new shiny OH WAI~~. A little too big




❖ Microframeworks like Cuba, NYNY




❖ Microframeworks like Cuba, NYNY - too much to write





❖ Roda





❖ Roda - a challenger appears. No one noticed






❖ Rack






❖ Rack - maybe easier to rewrite the whole stack from scratch?






❖ Rack - maybe easier to rewrite the whole stack from scratch? (And end up with buggy unfinished Rails)

If you can’t create it, steal it

WebMachine-ruby❖ Based on Erlang’s web machine


❖ Created by Sean Cribbs



❖ More than 5 years old




❖ Still alive!




❖ Still alive! Last commit - on 30 Jan 2017





❖ 13 issues opened and 80 closed






❖ Author works with Erlang, Ruby and Elixir






❖ Author works with Erlang, Ruby and Elixir

❖ github://webmachine/webmachine-ruby.git

github://webmachine/webmachine-ruby.git

Fundamental idea❖ Each API resource is a typical state machine


❖ Each request is a flow through this state machine



❖ Most requests are pretty standard




❖ Functional behavior is more suiting case for this




❖ Functional behavior is more suiting case for this

❖ Define standards and override only needed things

Why state machine?❖ Typical frameworks: request is running by predefined

procedure.


procedure. They are not your bros



❖ Webmachine determines facts about requests




❖ Uses finite state machine to determine proper response





❖ Each fact can easily be tested





❖ Each fact can easily be tested

❖ Webmachine is your bro

State machine diagram

Request to resource flow

Validation and authorization

Content negotiation

Existence and redirection

Conditional requests

PUT/POST (resource creation)

DELETE (resource deletion)

render body

How it parses your request?

Parsing request❖ Initial request: curl "http://localhost/kudos/1" -H "Accept: application/json" -u test -p test

Parsing request❖ Initial request:

curl "http://localhost/kudos/1" -H "Accept: application/json" -u test -p test

❖ Does route /kudos/:id exist?




❖ Does resource with ID 1 exist?





❖ Is this user with this password allowed to execute this request on resource?






❖ Can this method be called for this resource?






❖ Can this method be called for this resource?

❖ Can this resource be rendered with this content type?

Typical resourceclass KudoResource < Webmachine::Resource def allowed_methods ["GET"] end

def content_types_provided [["application/json", :to_json]] end

def resource_exists? kudo # Truthy or falsey end

def to_json kudo.to_json end

private

def kudo @kudo ||= Kudo.find(id) end

def id request.path_info[:id] end end

Little coding session

Bonus: request trace

Even more

Lattice: Webmachine on actors

Thank you!

Questions?

functional web apps with webmachine framework - mikhail bortnyk

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