aquarla/app.rb

## app.rb
require 'rubygems'
require 'sinatra'
require 'oauth2'
require 'securerandom'

use Rack::Session::Cookie,
  :expire_after => 86400,
  :secret => SecureRandom.hex(32)

APP_ID='1111111111111' # FacebookアプリのアプリケーションID
APP_SECRET='aaaaaaaaaaaaaaaaaa' # Facebookアプリのsecret
REDIRECT_URI='http://[ドメイン名]/callback' # リダイレクト用URIを指定する
SCOPE='offline_access' # 呼び出すAPIに応じて変える

@@client = OAuth2::Client.new(APP_ID, APP_SECRET,
  {:site => 'https://graph.facebook.com', :ssl => {:verify => false}, :parse_json => true})

get '/' do
  if session[:access_token]
    access_token = OAuth2::AccessToken.new(@@client, session[:access_token])
    @me = access_token.get("/me")
  end
  erb :index
end

get '/login' do
  redirect @@client.web_server.authorize_url(:redirect_uri => REDIRECT_URI, :scope => SCOPE)
end

get '/logout' do
  session[:access_token] = nil
  redirect '/'
end

get '/callback' do
  if params[:code]
    access_token = @@client.web_server.get_access_token(params[:code], :redirect_uri => REDIRECT_URI)
    session[:access_token] = access_token.token
    redirect '/'
  end
end

helpers do
  # ログアウト状態のときはログインリンク、ログイン状態のときはログアウトリンク
  def link_to_login_or_logout
    if session[:access_token]
      %Q(<a href="/logout">ログアウト</a>)
    else
      %Q(<a href="/login">ログイン</a>)
    end
  end

  # Hashをhtml table形式で出力する
  def to_html_table(hash)
    result = ""
    if hash
      result << "<table>"
      hash.each do |key, value|
        result << "<tr>"
        result << "<th>#{key}</th>"
        result << "<td>"
        if value.is_a?(Hash)
          result << to_html_table(value)
        elsif value.is_a?(Array)
          value.each do |v|
            result << to_html_table(v)
          end
        else
          result << "#{value}"
        end
        result << "</td>"
        result << "</tr>"
      end
      result << "</table>"
    end
    result
  end
end

__END__
__DATA__

@@ index
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8">
</head>
<body>
<%= link_to_login_or_logout %>
<%= to_html_table(@me) %>
</body>
</html>
	require 'rubygems'
	require 'sinatra'
	require 'oauth2'
	require 'securerandom'

	use Rack::Session::Cookie,
	:expire_after => 86400,
	:secret => SecureRandom.hex(32)

	APP_ID='1111111111111' # FacebookアプリのアプリケーションID
	APP_SECRET='aaaaaaaaaaaaaaaaaa' # Facebookアプリのsecret
	REDIRECT_URI='http://[ドメイン名]/callback' # リダイレクト用URIを指定する
	SCOPE='offline_access' # 呼び出すAPIに応じて変える

	@@client = OAuth2::Client.new(APP_ID, APP_SECRET,
	{:site => 'https://graph.facebook.com', :ssl => {:verify => false}, :parse_json => true})

	get '/' do
	if session[:access_token]
	access_token = OAuth2::AccessToken.new(@@client, session[:access_token])
	@me = access_token.get("/me")
	end
	erb :index
	end

	get '/login' do
	redirect @@client.web_server.authorize_url(:redirect_uri => REDIRECT_URI, :scope => SCOPE)
	end

	get '/logout' do
	session[:access_token] = nil
	redirect '/'
	end

	get '/callback' do
	if params[:code]
	access_token = @@client.web_server.get_access_token(params[:code], :redirect_uri => REDIRECT_URI)
	session[:access_token] = access_token.token
	redirect '/'
	end
	end

	helpers do
	# ログアウト状態のときはログインリンク、ログイン状態のときはログアウトリンク
	def link_to_login_or_logout
	if session[:access_token]
	%Q(<a href="/logout">ログアウト</a>)
	else
	%Q(<a href="/login">ログイン</a>)
	end
	end

	# Hashをhtml table形式で出力する
	def to_html_table(hash)
	result = ""
	if hash
	result << "<table>"
	hash.each do \|key, value\|
	result << "<tr>"
	result << "<th>#{key}</th>"
	result << "<td>"
	if value.is_a?(Hash)
	result << to_html_table(value)
	elsif value.is_a?(Array)
	value.each do \|v\|
	result << to_html_table(v)
	end
	else
	result << "#{value}"
	end
	result << "</td>"
	result << "</tr>"
	end
	result << "</table>"
	end
	result
	end
	end

	__END__
	__DATA__

	@@ index
	<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
	<html xmlns="http://www.w3.org/1999/xhtml">
	<head>
	<meta http-equiv="content-type" content="text/html; charset=utf-8">
	</head>
	<body>
	<%= link_to_login_or_logout %>
	<%= to_html_table(@me) %>
	</body>
	</html>