Building with Rack

Let's build a Rack app!

Transcript

1. Building with Rack
   Alexander Clark
   

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2. What is Rack?
   

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3. ?
   

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5. ?
   

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7. ?
   

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8. ?
   

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9. What does a Rack app look
   like?
   ?
   

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10. What does a Rack app look
    like?
    GET /foo HTTP/1.1
    Host: localhost:9292
    Accept: text/html
    …
    ?
    

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11. What does a Rack app look
    like?
    GET /foo HTTP/1.1
    Host: localhost:9292
    Accept: text/html
    …
    ?
    
    
    
    …
    

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12. run Proc.new { |env| ['200', {'Content-Type' => 'text/html'}, ['get rack\'d']] }
    

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13. run Proc.new { |env| ['200', {'Content-Type' => 'text/html'}, ['get rack\'d']] }
    Responds to #call
    HTTP Status code
    Headers
    Response body
    Run
    

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14. run Proc.new { |env| ['200', {'Content-Type' => 'text/html'}, ['get rack\'d']] }
    Responds to #call
    Much HTTP Status code
    Such Headers
    Response body
    Wow
    Run
    

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15. Let’s build something!
    

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17. 
    
    
    Is it April Fools?
    
    
    <%= @april_fools ? 'YES' : 'NO' %>
    
    
    

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18. require 'erb'
    class MyRackApp
    def initialize
    @april_fools = Time.now.strftime('%m%d') == '0401'
    end
    def call(_env)
    ['200', {'Content-Type' => 'text/html'}, view]
    end
    def view
    [ERB.new(template).result(binding)]
    end
    def template
    File.open('index.html.erb', 'r').read
    end
    end
    

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19. require './my_rack_app'
    run MyRackApp.new
    

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21. ?
    

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22. run Proc.new { |env| ['200', {'Content-Type' => 'text/html'}, ['get rack\'d']] }
    run MyRackApp.new
    ...
    def call(_env)
    ['200', {'Content-Type' => 'text/html'}, view]
    end
    

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23. run MyRackApp.new
    run Rails.application
    

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24. Middleware
    

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25. TL;DL
    

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26. Further Reading
    • https://rack.github.io/
    • http://alexander-clark.com/blog/building-a-rack-app/
    • http://www.justinweiss.com/articles/a-web-server-vs-
    an-app-server/
    • https://www.amberbit.com/blog/2011/07/13/
    introduction-to-rack-middleware/
    

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27. Thanks for Listening
    Alexander Clark
    atheclark
    alexander-clark.com
    alexander-clark
    

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