rails-controllers.md

   1 ---
   2 title: Controllers
   3 category: Rails
   4 ---
   5
   6 ### Common stuff
   7
   8     redirect_to root_url
   9     redirect_to root_url, notice: "Good."
  10
  11 ### Special hashes
  12
  13     session[:user_id] = nil
  14
  15     flash[:notice] = "Hello"    # Gets flushed on next request
  16     flash.keep                  # Persist flash values
  17     flash.now[:error] = "Boo"   # Available on the same request
  18
  19     cookies[:hello] = "Hi"
  20
  21     params[:page]
  22
  23     # params is a combination of:
  24     query_parameters
  25     path_parameters
  26     request_parameters
  27
  28 ### respond_to
  29
  30     respond_to do |format|
  31       format.html
  32       format.xml  { render xml: @users }
  33       format.json { render json: @users }
  34       format.js    # Will be executed by the browser
  35     end
  36
  37 ### default_url_options
  38
  39     # The options parameter is the hash passed in to 'url_for'
  40     def default_url_options(options)
  41       {:locale => I18n.locale}
  42     end
  43
  44 ### Filters
  45
  46     # Filter with callbacks
  47     before_filter :authenticate
  48     before_filter :authenticate, except: [:login]
  49     before_filter :authenticate, only: [:login]
  50     def authenticate
  51       redirect_to login_url unless controller.logged_in?
  52     end
  53
  54     # Filter with inline
  55     before_filter do |controller|
  56       redirect_to login_url unless controller.logged_in?
  57     end
  58
  59     # Filter with external classes
  60     before_filter LoginFilter
  61     class LoginFilter
  62       def self.filter(controller) ...; end
  63     end
  64
  65     # Filter exceptions
  66     skip_before_filter :require_login, only: [:new, :create]
  67
  68     # Before/after filters
  69     around_filter :wrap_in_transaction
  70     def wrap_in_transaction(&blk)
  71       ActiveRecord::Base.transaction { yield }
  72     end
  73
  74 ### HTTP basic authentication
  75
  76     before_filter :authenticate
  77
  78     # Basic authentication:
  79     def authenticate
  80       authenticate_or_request_with_http_basic { |u, p|
  81         u == "root" && p == "alpine"
  82       }
  83     end
  84
  85     # ...or digest (hashed) authentication:
  86     # uses the ha1 hash (username:realm:password)
  87     def authenticate_by_digest
  88       realm = "Secret3000"
  89       users = {
  90         "rsc" => Digest::MD5.hexdigest("rsc:#{realm}:passwordhere")
  91       }
  92
  93       authenticate_or_request_with_http_digest(realm) { |user|
  94         users[user]
  95       }
  96     end
  97
  98     # For integration tests
  99     def test_access
 100       auth = ActionController::HttpAuthentication::Basic.encode_credentials(user, pass)
 101       get "/notes/1.xml", nil, 'HTTP_AUTHORIZATION' => auth
 102     end
 103
 104     # Token auth
 105     is_logged_in = authenticate_with_http_token do |token, options|
 106       token == our_secret_token
 107     end
 108
 109     request_http_token_authentication  unless is_logged_in
 110
 111 ### Request/response
 112
 113     request.host            #=> "www.example.com"
 114     request.domain          #=> "www.example.com"
 115     request.domain(n=2)     #=> "example.com"
 116     request.port            #=> 80
 117     request.protocol        #=> "http://"
 118     request.query_string    #=> "q=duck+tales"
 119     request.url             #=> "http://www.example.com/search?q=duck+tales"
 120     request.fullpath        #=> "/search?q=duck+tales"
 121
 122     request.headers         # Returns a hash
 123
 124     request.format          #=> "text/html"
 125     request.remote_ip       #=> "203.167.220.220"
 126     request.local?          #=> true (if localhost/127.0.0.1)
 127
 128     request.xhr?
 129
 130     request.method          #=> "POST"
 131     request.method_symbol   #=> :post
 132     request.get?
 133     request.post?
 134     request.put?
 135     request.delete?
 136     request.head?
 137
 138 ### response
 139
 140     response.body
 141     response.status         #=> 404
 142     response.location       # Redirect location
 143     response.content_type
 144     response.charset
 145     response.headers
 146
 147     response.headers["Content-Type"] = "application/pdf"
 148
 149 ### Streaming
 150
 151     send_data pdfdata, filename: "foo.pdf", type: "application/pdf"
 152     send_file Rails.root.join('public','filename.txt') [filename: '..', type: '..']
 153
 154 ### References
 155
 156  * [Guide](http://guides.rubyonrails.org/action_controller_overview.html)
 157  * [HttpAuthentication::Basic](http://api.rubyonrails.org/classes/ActionController/HttpAuthentication/Basic.html)
 158  * [HttpAuthentication::Token](http://api.rubyonrails.org/classes/ActionController/HttpAuthentication/Token.html)