Rack

Rack Thomas R. Koll http://ananasblau.com [email protected]

What is Rack? ●

Rack is written in Ruby

●

Rack is a webserver framework

●

Rack is between the webserver and your app

●

Rack can be a webapp, if it's a simple task

●

Apps can be anything: Rails, Sinatra, merb etc.

●

Rack is dead simple, even I understood it

Internetto

Webserver Rack

Rails Application

sinatra Application

Specification ●

Rack is an Object

●

Rack has one method: call

●

call accepts one parameter: environment

●

environment is an hash with request info

●

Call must return an array with: ●

status code (1xx, 2xx, 3xx, 4xx, 5xx)

●

response headers is a hash with e.g. 'Content-Type'

●

body is used for the actual output

Example 1: simple server

Or use Rack::Directory

Example 2: root_path per domain ●

Allow customers to point domains to your app

●

Allow them to set a different root_path. E.g.

●

●

●

/albums/32

●

/blog/why-this-website-is-no-more

Dispatch subdomains to different controllers ●

/static/jobs for jobs.example.com

●

/blog for blog.example.com

●

/dashboard for dashboard.example.com

Could be done by mod_rewrite

DomainDispatcher

Example 3: Rack::Cache ●

Usually separate app/server like squid

●

In mephisto done via rewrite rules in webserver: ●

Not very flexible

●

Not very portable friendly

●

Separated from your app

RewriteCond %{REQUEST_URI} ^/[^.]+$ RewriteCond %{DOCUMENT_ROOT}/cache/%{HTTP_HOST}% {REQUEST_FILENAME}.html -f RewriteRule ^/(.*)$ /cache/%{HTTP_HOST}%{REQUEST_FILENAME}.html [QSA,L] RewriteCond %{REQUEST_URI} ^/.+$ RewriteCond %{DOCUMENT_ROOT}/cache/%{HTTP_HOST}% {REQUEST_FILENAME} -f RewriteRule ^/(.*)$ /cache/%{HTTP_HOST}%{REQUEST_FILENAME} [QSA,L]

Existing middleware There's plenty of stuff other contributed: ●

Rack::Cache

●

Rack::ETag

●

Rack::MailExceptions

●

Rack::Backstage

●

Rack::Auth::OpenID and Basic

●

Rack::Static

●

and many more...

Weblinks ●

http://rack.rubyforge.org

●

http://github.com/rack/rack-contrib/

●

http://tomayko.com/src/rack-cache/

●

http://guides.rubyonrails.org/rails_on_rack

●

http://railscasts.com/episodes/151-rack-middleware