SinatraAPI.rb – a one script REST API Server in Ruby

Now for some code

The Gist below is a work in progress. The goal is “A REST API Server in one script”. It’s just for learning purposes, not a serious effort.

This version has:

Resource model is a simple hash of Person objects, representing a team of three people to start with. No data mappers yet.
It supports all four CRUD verbs – POST, GET, PUT, DELETE respectively. Each should return a decent HTTP response code!
You can read the API with a browser or curl, but I use curl for the POST, PUT and DELETE. The API root has examples for you to copy and paste.
It has a basic X-Api-Version response header.
There’s no oauth nor any integration with any backend systems yet.

So, not much, but it achieves the goal so far so whatchagonnado?

#!/usr/bin/env ruby # # stevie_chambers@viewyonder.com July 2012 # # I'm playing around with APIs, and sharing my learnings # You can follow my trials and tribulations at http://viewyonder.com/apis # # This is a simple Ruby script to show how a simple API might work. # The resource model is just a simple array of a single class - no back-end store (yet) # # This will take browser/curl on all four CRUD verbs and hopefully give the right HTTP responses :) # # Open the API root for more 'documentation' require 'sinatra' require 'JSON' API_VERSION='2012-07-10' # Our complex resource model :) We have a hash of these, key is id. That's it; that's all class Person attr_accessor :id, :name def initialize(id,name) @id = id @name = name end end steve = Person.new('1','Steve') alan = Person.new('2','Alan') dave = Person.new('3','Dave') team = { '1' => steve, '2' => alan, '3' => dave } # This bad boy is called at the end of every route to push (some of) the client's request headers for debugging. def request_html(request) html = Array.new html << "<h3>Debugging</h3>" html << "<p>Team API Version X-Api-Header - #{API_VERSION}</p>" html << "<p>Request Method - #{request.request_method}</p>" html << "<p>URL - #{request.url}</p>" html << "<p>Accept - #{request.accept}</p>" html << "<p>Body - #{request.body}</p>" html << "<p>Query String - #{request.query_string}</p>" html << "<p>Content Length - #{request.content_length}</p>" html << "<p>Media Type - #{request.media_type}</p>" html << "<p>HEADER - #{request["SOME_HEADER"]}</p>" # Use this later to authentication html << "<p>User Agent - #{request.user_agent}</p>" html end def doc_html html = Array.new html << "<h3>Documentation</h3>" html << "<p>This version uses all the CRUD verbs - in order, POST, GET, PUT, DELETE.</p>" html << "<p>The only resource in the API is /api/team and in there each member has a unique number ID.</p>" html << "<p>This team resource is a simple hash of a simple class called Person with id and name attributes.</p>" html << %{<li>Create a specific resource: curl -X POST -i -d '{ "id": "666", "name" : "Jeramiah" }' http://localhost:4567/api/team/666</li>} html << %{<li>Read a specific resource: curl -X GET -i http://localhost:4567/api/team/666</li>} html << %{<li>Update a specific resource: curl -X PUT -i -d '{ "id": "666", "name" : "Satan" }' http://localhost:4567/api/team/666</li>} html << %{<li>Delete a specific resource: curl -X DELETE -i http://localhost:4567/api/team/666</li></ul>} html end # Sinatra server root, not the api root (that's /api, not /) get '/' do html = Array.new html << %{<h1>Sinatra Web Server</h1>} html << %{<h3>Resources</h3>} html << %{<p><a href="/api" rel="api">Team API Root End Point</a></p>} request_html(request).each { |p| html << p } status 200 # OK content_type 'text/html' body(html) end # The Team API root, so we give some useful info here on how to use, what's done, what's not done. get '/api/?' do html = Array.new html << %{<h1>Team API</h1>} doc_html.each { |p| html << p } html << %{<h3>Resources</h3>} html << %{<p><a href="/api/team" rel="team">Team Resources</a></p>} request_html(request).each { |p| html << p } status 200 # OK content_type 'text/html' body(html) end get '/api/team/?' do html = Array.new html << %{<h1>Team Resources</h1>} doc_html.each { |p| html << p } html << %{<h3>Resources</h3>} team.each do |key, person| html << %{<li><a href="/api/team/#{person.id}" rel="#{person.name}">#{person.name}</a></li>} end html << %{<p><a href="/api" rel="api">Team API Root End Point</a></p>} request_html(request).each { |p| html << p } status 200 # OK content_type 'text/html' body(html) end get '/api/team/:id' do person = team[params[:id]] if person.nil? then html = Array.new html << %{<h1>Team Resource - Error</h1>} html << %{<p>NOT FOUND: Unable to find the team member with ID: #{params[:id]}</p>} html << %{<p><a href="/api/team" rel="team">Team Resources</a></p>} request_html(request).each { |p| html << p } status 404 # Not Found content_type 'text/html' body(html) else html = Array.new doc_html.each { |p| html << p } html << %{<h1>Team Resource - #{person.name}</h1>} html << %{<p>ID - #{person.id}</p>} html << %{<p>Name - #{person.name}</p>} html << %{<p><a href="/api/team" rel="team">Team Resources</a></p>} request_html(request).each { |p| html << p } status 200 # OK content_type 'text/html' body(html) end end delete '/api/team/:id' do person = team[params[:id]] if person.nil? then html = Array.new html << %{<h1>Team Resource</h1>} html << %{<p>NOT FOUND: Unable to find the team member with ID: #{params[:id]}</p>} html << %{<p><a href="/api/team" rel="team">Team Resources</a></p>} request_html(request).each { |p| html << p } status 404 # Not Found content_type 'text/html' body(html) else name = team[params[:id]].name team.delete(params[:id]) html = Array.new html << %{<h1>Team Resource</h1>} html << %{<p>ACCEPTED: Deleted team member #{name} with ID #{params[:id]}</p>}# html << %{<p><a href="/api/team" rel="team">Team Resources</a></p>} request_html(request).each { |p| html << p } status 202 # Accepted content_type 'text/html' body(html) end end post '/api/team/:id' do data = JSON.parse(request.body.string) if data.nil? or !data.has_key?('id') or !data.has_key?('name') then html = Array.new html << %{<h1>Team Resources</h1>} html << %{<p>BAD REQUEST: Unable to create the team member, insufficient data (missing id or name)</p>} html << %{<p><a href="/api/team" rel="team">Team Resources</a></p>} request_html(request).each { |p| html << p } status 400 # Bad Request content_type 'text/html' body(html) else html = Array.new html << %{<h1>Team Resourcer</h1>} if team[data['id']] then html << %{<p>FORBIDDEN: Unable to create the team member, id #{data['id']} already exists</p>} html << %{<p><a href="/api/team/#{data['id']}">Go to see existing team member</a></p>} status 403 # Forbidden else person = Person.new(data['id'],data['name']) team[data['id']] = person html << %{<p>CREATED: id: #{person.id} name: #{person.name}</p>} status 201 # Created end html << %{<p><a href="/api/team" rel="team">Team Resources</a></p>} request_html(request).each { |p| html << p } content_type 'text/html' body(html) end end put '/api/team/:id' do data = JSON.parse(request.body.string) if data.nil? or !data.has_key?('id') or !data.has_key?('name') then html = Array.new html << %{<h1>Team Resources</h1>} html << %{<p>BAD REQUEST: Unable to update the team member, insufficient request data (missing id or name)</p>} html << %{<p><a href="/api/team" rel="team">Team Resources</a></p>} request_html(request).each { |p| html << p } status 400 # Bad Request content_type 'text/html' body(html) else html = Array.new html << %{<h1>Team Resourcer</h1>} if !team[data['id']] then html << %{<p>NOT FOUND: Unable to update the team member, id #{data['id']} doesn't exist</p>} status 404 # Not Found else person = Person.new(data['id'],data['name']) team[data['id']] = person html << %{<p>ACCEPTED: Updated team member id #{person.id} to #{person.name}</p>} status 202 # Accepted end html << %{<p><a href="/api/team" rel="team">Team Resources</a></p>} request_html(request).each { |p| html << p } content_type 'text/html' body(html) end end after do response['X-Api-Header'] = API_VERSION end

SinatraAPI.rb – a one script REST API Server in Ruby

Now for some code

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