ちょっとわかるrack

初心者向けrackの簡単な紹介
・rackとは何か
・rackアプリの作り方
・rack middlewareの作り方・使い方

※2012/5/14の会社内LTで使用した資料

Transcript

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2. Web Server
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3. Web Server
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4. Web Server
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5. Web Server
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6. call(env)
   

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7. def call(env)
   ...
   end
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   [status, headers, response_body]
   

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8. ৄࡉ͸41&$Ͱ
   http://rack.rubyforge.org/doc/SPEC.html
   

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9. 4JOBUSBͷ৔߹
   

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10. # Rack call interface.
    def call(env)
    dup.call!(env)
    end
    attr_accessor :env, :request, :response, :params
    def call!(env) # :nodoc:
    @env = env
    @request = Request.new(env)
    @response = Response.new
    @params = indifferent_params(@request.params)
    template_cache.clear if settings.reload_templates
    force_encoding(@params)
    @response['Content-Type'] = nil
    invoke { dispatch! }
    invoke { error_block!(response.status) }
    unless @response['Content-Type']
    if Array === body and body[0].respond_to? :content_type
    content_type body[0].content_type
    else
    content_type :html
    end
    end
    @response.finish
    end
    

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11. SBDLVQ
    

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12. rackup config.ru
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    Rack::Builder.new { }.to_app
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13. #config.ru
    require ‘rack’
    require ‘myapp’
    run MyApp.new
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    JFJNQMFNFOUTcall(env)
    

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14. # Minimum config.ru
    require ‘rack’
    run lambda { |env|
    [200, { "Content-Type" => "text/plain" }, ["OK"] ]
    }
    TUBUVT IFBEFST CPEZ
    

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15. 3BDL.JEEMFXBSF
    

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16. Web Server
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    Middleware
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    ^
    

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17. w $43'
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    FUD
    

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18. class Middleware
    def initialize(app)
    @app = app
    end
    def call(env)
    # do something
    response = @app.call(env)
    # do something
    end
    end
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19. &YBNQMFSBDL@DTSG
    

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20. def call(env)
    unless env['rack.session']
    raise SessionUnavailable.new('Rack::Csrf depends on session middleware')
    end
    self.class.token(env)
    req = Rack::Request.new(env)
    untouchable = skip_checking(req) ||
    !@http_methods.include?(req.request_method) ||
    req.params[self.class.field] == env['rack.session'][self.class.key] ||
    req.env[self.class.rackified_header] == env['rack.session'][self.class.key]
    if untouchable
    @app.call(env)
    else
    raise InvalidCsrfToken if @raisable
    [403, {'Content-Type' => 'text/html', 'Content-Length' => '0'}, []]
    end
    end
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21. 6TJOH.JEEMFXBSF
    

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22. #config.ru
    require ‘rack’
    require ‘myapp’
    class Middleware
    def initialize(app)
    @app = app
    end
    def call(env)
    env["rack.some_header"] = "setting an
    example"
    @app.call(env)
    end
    end
    use Middleware
    run MyApp.new
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