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diff --git a/guides/source/action_controller_overview.md b/guides/source/action_controller_overview.md index 21fb11c89c..c78618c4f4 100644 --- a/guides/source/action_controller_overview.md +++ b/guides/source/action_controller_overview.md @@ -27,7 +27,7 @@ NOTE: For more details on the routing process, see "Rails Routing from the Outsi Methods and Actions ------------------- -A controller is a Ruby class which inherits from +ApplicationController+ and has methods just like any other class. When your application receives a request, the routing will determine which controller and action to run, then Rails creates an instance of that controller and runs the method with the same name as the action. +A controller is a Ruby class which inherits from `ApplicationController` and has methods just like any other class. When your application receives a request, the routing will determine which controller and action to run, then Rails creates an instance of that controller and runs the method with the same name as the action. ```ruby class ClientsController < ApplicationController @@ -36,7 +36,7 @@ class ClientsController < ApplicationController end ``` -As an example, if a user goes to +/clients/new+ in your application to add a new client, Rails will create an instance of +ClientsController+ and run the +new+ method. Note that the empty method from the example above could work just fine because Rails will by default render the +new.html.erb+ view unless the action says otherwise. The +new+ method could make available to the view a +@client+ instance variable by creating a new +Client+: +As an example, if a user goes to `/clients/new` in your application to add a new client, Rails will create an instance of `ClientsController` and run the `new` method. Note that the empty method from the example above could work just fine because Rails will by default render the `new.html.erb` view unless the action says otherwise. The `new` method could make available to the view a `@client` instance variable by creating a new `Client`: ```ruby def new @@ -46,14 +46,14 @@ end The "Layouts & Rendering Guide":layouts_and_rendering.html explains this in more detail. -+ApplicationController+ inherits from +ActionController::Base+, which defines a number of helpful methods. This guide will cover some of these, but if you're curious to see what's in there, you can see all of them in the API documentation or in the source itself. +`ApplicationController` inherits from `ActionController::Base`, which defines a number of helpful methods. This guide will cover some of these, but if you're curious to see what's in there, you can see all of them in the API documentation or in the source itself. Only public methods are callable as actions. It is a best practice to lower the visibility of methods which are not intended to be actions, like auxiliary methods or filters. Parameters ---------- -You will probably want to access data sent in by the user or other parameters in your controller actions. There are two kinds of parameters possible in a web application. The first are parameters that are sent as part of the URL, called query string parameters. The query string is everything after "?" in the URL. The second type of parameter is usually referred to as POST data. This information usually comes from an HTML form which has been filled in by the user. It's called POST data because it can only be sent as part of an HTTP POST request. Rails does not make any distinction between query string parameters and POST parameters, and both are available in the +params+ hash in your controller: +You will probably want to access data sent in by the user or other parameters in your controller actions. There are two kinds of parameters possible in a web application. The first are parameters that are sent as part of the URL, called query string parameters. The query string is everything after "?" in the URL. The second type of parameter is usually referred to as POST data. This information usually comes from an HTML form which has been filled in by the user. It's called POST data because it can only be sent as part of an HTTP POST request. Rails does not make any distinction between query string parameters and POST parameters, and both are available in the `params` hash in your controller: ```ruby class ClientsController < ActionController::Base @@ -89,7 +89,7 @@ end ### Hash and Array Parameters -The +params+ hash is not limited to one-dimensional keys and values. It can contain arrays and (nested) hashes. To send an array of values, append an empty pair of square brackets "[]" to the key name: +The `params` hash is not limited to one-dimensional keys and values. It can contain arrays and (nested) hashes. To send an array of values, append an empty pair of square brackets "[]" to the key name: ``` GET /clients?ids[]=1&ids[]=2&ids[]=3 @@ -97,7 +97,7 @@ GET /clients?ids[]=1&ids[]=2&ids[]=3 NOTE: The actual URL in this example will be encoded as "/clients?ids%5b%5d=1&ids%5b%5d=2&ids%5b%5d=3" as "[" and "]" are not allowed in URLs. Most of the time you don't have to worry about this because the browser will take care of it for you, and Rails will decode it back when it receives it, but if you ever find yourself having to send those requests to the server manually you have to keep this in mind. -The value of +params[:ids]+ will now be +["1", "2", "3"]+. Note that parameter values are always strings; Rails makes no attempt to guess or cast the type. +The value of `params[:ids]` will now be `["1", "2", "3"]`. Note that parameter values are always strings; Rails makes no attempt to guess or cast the type. To send a hash you include the key name inside the brackets: @@ -110,13 +110,13 @@ To send a hash you include the key name inside the brackets: </form> ``` -When this form is submitted, the value of +params[:client]+ will be `{"name" => "Acme", "phone" => "12345", "address" => {"postcode" => "12345", "city" => "Carrot City"}}`. Note the nested hash in +params[:client][:address]+. +When this form is submitted, the value of `params[:client]` will be `{"name" => "Acme", "phone" => "12345", "address" => {"postcode" => "12345", "city" => "Carrot City"}}`. Note the nested hash in `params[:client][:address]`. -Note that the +params+ hash is actually an instance of +HashWithIndifferentAccess+ from Active Support, which acts like a hash that lets you use symbols and strings interchangeably as keys. +Note that the `params` hash is actually an instance of `HashWithIndifferentAccess` from Active Support, which acts like a hash that lets you use symbols and strings interchangeably as keys. ### JSON/XML parameters -If you're writing a web service application, you might find yourself more comfortable on accepting parameters in JSON or XML format. Rails will automatically convert your parameters into +params+ hash, which you'll be able to access like you would normally do with form data. +If you're writing a web service application, you might find yourself more comfortable on accepting parameters in JSON or XML format. Rails will automatically convert your parameters into `params` hash, which you'll be able to access like you would normally do with form data. So for example, if you are sending this JSON parameter: @@ -126,13 +126,13 @@ So for example, if you are sending this JSON parameter: You'll get `params[:company]` as `{ :name => "acme", "address" => "123 Carrot Street" }`. -Also, if you've turned on +config.wrap_parameters+ in your initializer or calling +wrap_parameters+ in your controller, you can safely omit the root element in the JSON/XML parameter. The parameters will be cloned and wrapped in the key according to your controller's name by default. So the above parameter can be written as: +Also, if you've turned on `config.wrap_parameters` in your initializer or calling `wrap_parameters` in your controller, you can safely omit the root element in the JSON/XML parameter. The parameters will be cloned and wrapped in the key according to your controller's name by default. So the above parameter can be written as: ``` { "name": "acme", "address": "123 Carrot Street" } ``` -And assume that you're sending the data to +CompaniesController+, it would then be wrapped in +:company+ key like this: +And assume that you're sending the data to `CompaniesController`, it would then be wrapped in `:company` key like this: ```ruby { :name => "acme", :address => "123 Carrot Street", :company => { :name => "acme", :address => "123 Carrot Street" }} @@ -142,17 +142,17 @@ You can customize the name of the key or specific parameters you want to wrap by ### Routing Parameters -The +params+ hash will always contain the +:controller+ and +:action+ keys, but you should use the methods +controller_name+ and +action_name+ instead to access these values. Any other parameters defined by the routing, such as +:id+ will also be available. As an example, consider a listing of clients where the list can show either active or inactive clients. We can add a route which captures the +:status+ parameter in a "pretty" URL: +The `params` hash will always contain the `:controller` and `:action` keys, but you should use the methods `controller_name` and `action_name` instead to access these values. Any other parameters defined by the routing, such as `:id` will also be available. As an example, consider a listing of clients where the list can show either active or inactive clients. We can add a route which captures the `:status` parameter in a "pretty" URL: ```ruby match '/clients/:status' => 'clients#index', :foo => "bar" ``` -In this case, when a user opens the URL +/clients/active+, +params[:status]+ will be set to "active". When this route is used, +params[:foo]+ will also be set to "bar" just like it was passed in the query string. In the same way +params[:action]+ will contain "index". +In this case, when a user opens the URL `/clients/active`, `params[:status]` will be set to "active". When this route is used, `params[:foo]` will also be set to "bar" just like it was passed in the query string. In the same way `params[:action]` will contain "index". -### +default_url_options+ +### `default_url_options` -You can set global default parameters for URL generation by defining a method called +default_url_options+ in your controller. Such a method must return a hash with the desired defaults, whose keys must be symbols: +You can set global default parameters for URL generation by defining a method called `default_url_options` in your controller. Such a method must return a hash with the desired defaults, whose keys must be symbols: ```ruby class ApplicationController < ActionController::Base @@ -162,9 +162,9 @@ class ApplicationController < ActionController::Base end ``` -These options will be used as a starting point when generating URLs, so it's possible they'll be overridden by the options passed in +url_for+ calls. +These options will be used as a starting point when generating URLs, so it's possible they'll be overridden by the options passed in `url_for` calls. -If you define +default_url_options+ in +ApplicationController+, as in the example above, it would be used for all URL generation. The method can also be defined in one specific controller, in which case it only affects URLs generated there. +If you define `default_url_options` in `ApplicationController`, as in the example above, it would be used for all URL generation. The method can also be defined in one specific controller, in which case it only affects URLs generated there. Session @@ -187,7 +187,7 @@ If your user sessions don't store critical data or don't need to be around for l Read more about session storage in the "Security Guide":security.html. -If you need a different session storage mechanism, you can change it in the +config/initializers/session_store.rb+ file: +If you need a different session storage mechanism, you can change it in the `config/initializers/session_store.rb` file: ```ruby # Use the database for sessions instead of the cookie-based default, @@ -196,7 +196,7 @@ If you need a different session storage mechanism, you can change it in the +con # YourApp::Application.config.session_store :active_record_store ``` -Rails sets up a session key (the name of the cookie) when signing the session data. These can also be changed in +config/initializers/session_store.rb+: +Rails sets up a session key (the name of the cookie) when signing the session data. These can also be changed in `config/initializers/session_store.rb`: ```ruby # Be sure to restart your server when you modify this file. @@ -204,7 +204,7 @@ Rails sets up a session key (the name of the cookie) when signing the session da YourApp::Application.config.session_store :cookie_store, :key => '_your_app_session' ``` -You can also pass a +:domain+ key and specify the domain name for the cookie: +You can also pass a `:domain` key and specify the domain name for the cookie: ```ruby # Be sure to restart your server when you modify this file. @@ -212,7 +212,7 @@ You can also pass a +:domain+ key and specify the domain name for the cookie: YourApp::Application.config.session_store :cookie_store, :key => '_your_app_session', :domain => ".example.com" ``` -Rails sets up (for the CookieStore) a secret key used for signing the session data. This can be changed in +config/initializers/secret_token.rb+ +Rails sets up (for the CookieStore) a secret key used for signing the session data. This can be changed in `config/initializers/secret_token.rb` ```ruby # Be sure to restart your server when you modify this file. @@ -224,11 +224,11 @@ Rails sets up (for the CookieStore) a secret key used for signing the session da YourApp::Application.config.secret_token = '49d3f3de9ed86c74b94ad6bd0...' ``` -NOTE: Changing the secret when using the +CookieStore+ will invalidate all existing sessions. +NOTE: Changing the secret when using the `CookieStore` will invalidate all existing sessions. ### Accessing the Session -In your controller you can access the session through the +session+ instance method. +In your controller you can access the session through the `session` instance method. NOTE: Sessions are lazily loaded. If you don't access sessions in your action's code, they will not be loaded. Hence you will never need to disable sessions, just not accessing them will do the job. @@ -266,7 +266,7 @@ class LoginsController < ApplicationController end ``` -To remove something from the session, assign that key to be +nil+: +To remove something from the session, assign that key to be `nil`: ```ruby class LoginsController < ApplicationController @@ -279,7 +279,7 @@ class LoginsController < ApplicationController end ``` -To reset the entire session, use +reset_session+. +To reset the entire session, use `reset_session`. ### The Flash @@ -299,7 +299,7 @@ class LoginsController < ApplicationController end ``` -Note that it is also possible to assign a flash message as part of the redirection. You can assign +:notice+, +:alert+ or the general purpose +:flash+: +Note that it is also possible to assign a flash message as part of the redirection. You can assign `:notice`, `:alert` or the general purpose `:flash`: ```ruby redirect_to root_url, :notice => "You have successfully logged out." @@ -307,7 +307,7 @@ redirect_to root_url, :alert => "You're stuck here!" redirect_to root_url, :flash => { :referral_code => 1234 } ``` -The +destroy+ action redirects to the application's +root_url+, where the message will be displayed. Note that it's entirely up to the next action to decide what, if anything, it will do with what the previous action put in the flash. It's conventional to display any error alerts or notices from the flash in the application's layout: +The `destroy` action redirects to the application's `root_url`, where the message will be displayed. Note that it's entirely up to the next action to decide what, if anything, it will do with what the previous action put in the flash. It's conventional to display any error alerts or notices from the flash in the application's layout: ```ruby <html> @@ -334,7 +334,7 @@ You can pass anything that the session can store; you're not limited to notices <% end %> ``` -If you want a flash value to be carried over to another request, use the +keep+ method: +If you want a flash value to be carried over to another request, use the `keep` method: ```ruby class MainController < ApplicationController @@ -354,9 +354,9 @@ class MainController < ApplicationController end ``` -#### +flash.now+ +#### `flash.now` -By default, adding values to the flash will make them available to the next request, but sometimes you may want to access those values in the same request. For example, if the +create+ action fails to save a resource and you render the +new+ template directly, that's not going to result in a new request, but you may still want to display a message using the flash. To do this, you can use +flash.now+ in the same way you use the normal +flash+: +By default, adding values to the flash will make them available to the next request, but sometimes you may want to access those values in the same request. For example, if the `create` action fails to save a resource and you render the `new` template directly, that's not going to result in a new request, but you may still want to display a message using the flash. To do this, you can use `flash.now` in the same way you use the normal `flash`: ```ruby class ClientsController < ApplicationController @@ -375,7 +375,7 @@ end Cookies ------- -Your application can store small amounts of data on the client -- called cookies -- that will be persisted across requests and even sessions. Rails provides easy access to cookies via the +cookies+ method, which -- much like the +session+ -- works like a hash: +Your application can store small amounts of data on the client -- called cookies -- that will be persisted across requests and even sessions. Rails provides easy access to cookies via the `cookies` method, which -- much like the `session` -- works like a hash: ```ruby class CommentsController < ApplicationController @@ -403,12 +403,12 @@ class CommentsController < ApplicationController end ``` -Note that while for session values you set the key to +nil+, to delete a cookie value you should use +cookies.delete(:key)+. +Note that while for session values you set the key to `nil`, to delete a cookie value you should use `cookies.delete(:key)`. Rendering xml and json data --------------------------- -ActionController makes it extremely easy to render +xml+ or +json+ data. If you generate a controller using scaffold then your controller would look something like this. +ActionController makes it extremely easy to render `xml` or `json` data. If you generate a controller using scaffold then your controller would look something like this. ```ruby class UsersController < ApplicationController @@ -423,7 +423,7 @@ class UsersController < ApplicationController end ``` -Notice that in the above case code is `render :xml => @users` and not `render :xml => @users.to_xml`. That is because if the input is not string then rails automatically invokes +to_xml+ . +Notice that in the above case code is `render :xml => @users` and not `render :xml => @users.to_xml`. That is because if the input is not string then rails automatically invokes `to_xml` . Filters @@ -431,7 +431,7 @@ Filters Filters are methods that are run before, after or "around" a controller action. -Filters are inherited, so if you set a filter on +ApplicationController+, it will be run on every controller in your application. +Filters are inherited, so if you set a filter on `ApplicationController`, it will be run on every controller in your application. Before filters may halt the request cycle. A common before filter is one which requires that a user is logged in for an action to be run. You can define the filter method this way: @@ -461,7 +461,7 @@ end The method simply stores an error message in the flash and redirects to the login form if the user is not logged in. If a before filter renders or redirects, the action will not run. If there are additional filters scheduled to run after that filter they are also cancelled. -In this example the filter is added to +ApplicationController+ and thus all controllers in the application inherit it. This will make everything in the application require the user to be logged in in order to use it. For obvious reasons (the user wouldn't be able to log in in the first place!), not all controllers or actions should require this. You can prevent this filter from running before particular actions with +skip_before_filter+: +In this example the filter is added to `ApplicationController` and thus all controllers in the application inherit it. This will make everything in the application require the user to be logged in in order to use it. For obvious reasons (the user wouldn't be able to log in in the first place!), not all controllers or actions should require this. You can prevent this filter from running before particular actions with `skip_before_filter`: ```ruby class LoginsController < ApplicationController @@ -469,7 +469,7 @@ class LoginsController < ApplicationController end ``` -Now, the +LoginsController+'s +new+ and +create+ actions will work as before without requiring the user to be logged in. The +:only+ option is used to only skip this filter for these actions, and there is also an +:except+ option which works the other way. These options can be used when adding filters too, so you can add a filter which only runs for selected actions in the first place. +Now, the `LoginsController`'s `new` and `create` actions will work as before without requiring the user to be logged in. The `:only` option is used to only skip this filter for these actions, and there is also an `:except` option which works the other way. These options can be used when adding filters too, so you can add a filter which only runs for selected actions in the first place. ### After Filters and Around Filters @@ -507,7 +507,7 @@ You can choose not to yield and build the response yourself, in which case the a While the most common way to use filters is by creating private methods and using *_filter to add them, there are two other ways to do the same thing. -The first is to use a block directly with the *_filter methods. The block receives the controller as an argument, and the +require_login+ filter from above could be rewritten to use a block: +The first is to use a block directly with the *_filter methods. The block receives the controller as an argument, and the `require_login` filter from above could be rewritten to use a block: ```ruby class ApplicationController < ActionController::Base @@ -517,7 +517,7 @@ class ApplicationController < ActionController::Base end ``` -Note that the filter in this case uses +send+ because the +logged_in?+ method is private and the filter is not run in the scope of the controller. This is not the recommended way to implement this particular filter, but in more simple cases it might be useful. +Note that the filter in this case uses `send` because the `logged_in?` method is private and the filter is not run in the scope of the controller. This is not the recommended way to implement this particular filter, but in more simple cases it might be useful. The second way is to use a class (actually, any object that responds to the right methods will do) to handle the filtering. This is useful in cases that are more complex and can not be implemented in a readable and reusable way using the two other methods. As an example, you could rewrite the login filter again to use a class: @@ -536,7 +536,7 @@ class LoginFilter end ``` -Again, this is not an ideal example for this filter, because it's not run in the scope of the controller but gets the controller passed as an argument. The filter class has a class method +filter+ which gets run before or after the action, depending on if it's a before or after filter. Classes used as around filters can also use the same +filter+ method, which will get run in the same way. The method must +yield+ to execute the action. Alternatively, it can have both a +before+ and an +after+ method that are run before and after the action. +Again, this is not an ideal example for this filter, because it's not run in the scope of the controller but gets the controller passed as an argument. The filter class has a class method `filter` which gets run before or after the action, depending on if it's a before or after filter. Classes used as around filters can also use the same `filter` method, which will get run in the same way. The method must `yield` to execute the action. Alternatively, it can have both a `before` and an `after` method that are run before and after the action. Request Forgery Protection -------------------------- @@ -567,24 +567,24 @@ You will see how the token gets added as a hidden field: </form> ``` -Rails adds this token to every form that's generated using the "form helpers":form_helpers.html, so most of the time you don't have to worry about it. If you're writing a form manually or need to add the token for another reason, it's available through the method +form_authenticity_token+: +Rails adds this token to every form that's generated using the "form helpers":form_helpers.html, so most of the time you don't have to worry about it. If you're writing a form manually or need to add the token for another reason, it's available through the method `form_authenticity_token`: -The +form_authenticity_token+ generates a valid authentication token. That's useful in places where Rails does not add it automatically, like in custom Ajax calls. +The `form_authenticity_token` generates a valid authentication token. That's useful in places where Rails does not add it automatically, like in custom Ajax calls. The "Security Guide":security.html has more about this and a lot of other security-related issues that you should be aware of when developing a web application. The Request and Response Objects -------------------------------- -In every controller there are two accessor methods pointing to the request and the response objects associated with the request cycle that is currently in execution. The +request+ method contains an instance of +AbstractRequest+ and the +response+ method returns a response object representing what is going to be sent back to the client. +In every controller there are two accessor methods pointing to the request and the response objects associated with the request cycle that is currently in execution. The `request` method contains an instance of `AbstractRequest` and the `response` method returns a response object representing what is going to be sent back to the client. -### The +request+ Object +### The `request` Object The request object contains a lot of useful information about the request coming in from the client. To get a full list of the available methods, refer to the "API documentation":http://api.rubyonrails.org/classes/ActionDispatch/Request.html. Among the properties that you can access on this object are: -|_.Property of +request+|_.Purpose| +|_.Property of `request`|_.Purpose| |host|The hostname used for this request.| -|domain(n=2)|The hostname's first +n+ segments, starting from the right (the TLD).| +|domain(n=2)|The hostname's first `n` segments, starting from the right (the TLD).| |format|The content type requested by the client.| |method|The HTTP method used for the request.| |get?, post?, patch?, put?, delete?, head?|Returns true if the HTTP method is GET/POST/PATCH/PUT/DELETE/HEAD.| @@ -595,15 +595,15 @@ The request object contains a lot of useful information about the request coming |remote_ip|The IP address of the client.| |url|The entire URL used for the request.| -#### +path_parameters+, +query_parameters+, and +request_parameters+ +#### `path_parameters`, `query_parameters`, and `request_parameters` -Rails collects all of the parameters sent along with the request in the +params+ hash, whether they are sent as part of the query string or the post body. The request object has three accessors that give you access to these parameters depending on where they came from. The +query_parameters+ hash contains parameters that were sent as part of the query string while the +request_parameters+ hash contains parameters sent as part of the post body. The +path_parameters+ hash contains parameters that were recognized by the routing as being part of the path leading to this particular controller and action. +Rails collects all of the parameters sent along with the request in the `params` hash, whether they are sent as part of the query string or the post body. The request object has three accessors that give you access to these parameters depending on where they came from. The `query_parameters` hash contains parameters that were sent as part of the query string while the `request_parameters` hash contains parameters sent as part of the post body. The `path_parameters` hash contains parameters that were recognized by the routing as being part of the path leading to this particular controller and action. -### The +response+ Object +### The `response` Object The response object is not usually used directly, but is built up during the execution of the action and rendering of the data that is being sent back to the user, but sometimes - like in an after filter - it can be useful to access the response directly. Some of these accessor methods also have setters, allowing you to change their values. -|_.Property of +response+|_.Purpose| +|_.Property of `response`|_.Purpose| |body|This is the string of data being sent back to the client. This is most often HTML.| |status|The HTTP status code for the response, like 200 for a successful request or 404 for file not found.| |location|The URL the client is being redirected to, if any.| @@ -613,7 +613,7 @@ The response object is not usually used directly, but is built up during the exe #### Setting Custom Headers -If you want to set custom headers for a response then +response.headers+ is the place to do it. The headers attribute is a hash which maps header names to their values, and Rails will set some of them automatically. If you want to add or change a header, just assign it to +response.headers+ this way: +If you want to set custom headers for a response then `response.headers` is the place to do it. The headers attribute is a hash which maps header names to their values, and Rails will set some of them automatically. If you want to add or change a header, just assign it to `response.headers` this way: ```ruby response.headers["Content-Type"] = "application/pdf" @@ -629,7 +629,7 @@ Rails comes with two built-in HTTP authentication mechanisms: ### HTTP Basic Authentication -HTTP basic authentication is an authentication scheme that is supported by the majority of browsers and other HTTP clients. As an example, consider an administration section which will only be available by entering a username and a password into the browser's HTTP basic dialog window. Using the built-in authentication is quite easy and only requires you to use one method, +http_basic_authenticate_with+. +HTTP basic authentication is an authentication scheme that is supported by the majority of browsers and other HTTP clients. As an example, consider an administration section which will only be available by entering a username and a password into the browser's HTTP basic dialog window. Using the built-in authentication is quite easy and only requires you to use one method, `http_basic_authenticate_with`. ```ruby class AdminController < ApplicationController @@ -637,11 +637,11 @@ class AdminController < ApplicationController end ``` -With this in place, you can create namespaced controllers that inherit from +AdminController+. The filter will thus be run for all actions in those controllers, protecting them with HTTP basic authentication. +With this in place, you can create namespaced controllers that inherit from `AdminController`. The filter will thus be run for all actions in those controllers, protecting them with HTTP basic authentication. ### HTTP Digest Authentication -HTTP digest authentication is superior to the basic authentication as it does not require the client to send an unencrypted password over the network (though HTTP basic authentication is safe over HTTPS). Using digest authentication with Rails is quite easy and only requires using one method, +authenticate_or_request_with_http_digest+. +HTTP digest authentication is superior to the basic authentication as it does not require the client to send an unencrypted password over the network (though HTTP basic authentication is safe over HTTPS). Using digest authentication with Rails is quite easy and only requires using one method, `authenticate_or_request_with_http_digest`. ```ruby class AdminController < ApplicationController @@ -659,14 +659,14 @@ class AdminController < ApplicationController end ``` -As seen in the example above, the +authenticate_or_request_with_http_digest+ block takes only one argument - the username. And the block returns the password. Returning +false+ or +nil+ from the +authenticate_or_request_with_http_digest+ will cause authentication failure. +As seen in the example above, the `authenticate_or_request_with_http_digest` block takes only one argument - the username. And the block returns the password. Returning `false` or `nil` from the `authenticate_or_request_with_http_digest` will cause authentication failure. Streaming and File Downloads ---------------------------- -Sometimes you may want to send a file to the user instead of rendering an HTML page. All controllers in Rails have the +send_data+ and the +send_file+ methods, which will both stream data to the client. +send_file+ is a convenience method that lets you provide the name of a file on the disk and it will stream the contents of that file for you. +Sometimes you may want to send a file to the user instead of rendering an HTML page. All controllers in Rails have the `send_data` and the `send_file` methods, which will both stream data to the client. `send_file` is a convenience method that lets you provide the name of a file on the disk and it will stream the contents of that file for you. -To stream data to the client, use +send_data+: +To stream data to the client, use `send_data`: ```ruby require "prawn" @@ -692,11 +692,11 @@ class ClientsController < ApplicationController end ``` -The +download_pdf+ action in the example above will call a private method which actually generates the PDF document and returns it as a string. This string will then be streamed to the client as a file download and a filename will be suggested to the user. Sometimes when streaming files to the user, you may not want them to download the file. Take images, for example, which can be embedded into HTML pages. To tell the browser a file is not meant to be downloaded, you can set the +:disposition+ option to "inline". The opposite and default value for this option is "attachment". +The `download_pdf` action in the example above will call a private method which actually generates the PDF document and returns it as a string. This string will then be streamed to the client as a file download and a filename will be suggested to the user. Sometimes when streaming files to the user, you may not want them to download the file. Take images, for example, which can be embedded into HTML pages. To tell the browser a file is not meant to be downloaded, you can set the `:disposition` option to "inline". The opposite and default value for this option is "attachment". ### Sending Files -If you want to send a file that already exists on disk, use the +send_file+ method. +If you want to send a file that already exists on disk, use the `send_file` method. ```ruby class ClientsController < ApplicationController @@ -710,9 +710,9 @@ class ClientsController < ApplicationController end ``` -This will read and stream the file 4kB at the time, avoiding loading the entire file into memory at once. You can turn off streaming with the +:stream+ option or adjust the block size with the +:buffer_size+ option. +This will read and stream the file 4kB at the time, avoiding loading the entire file into memory at once. You can turn off streaming with the `:stream` option or adjust the block size with the `:buffer_size` option. -If +:type+ is not specified, it will be guessed from the file extension specified in +:filename+. If the content type is not registered for the extension, `application/octet-stream` will be used. +If `:type` is not specified, it will be guessed from the file extension specified in `:filename`. If the content type is not registered for the extension, `application/octet-stream` will be used. WARNING: Be careful when using data coming from the client (params, cookies, etc.) to locate the file on disk, as this is a security risk that might allow someone to gain access to files they are not meant to see. @@ -720,7 +720,7 @@ TIP: It is not recommended that you stream static files through Rails if you can ### RESTful Downloads -While +send_data+ works just fine, if you are creating a RESTful application having separate actions for file downloads is usually not necessary. In REST terminology, the PDF file from the example above can be considered just another representation of the client resource. Rails provides an easy and quite sleek way of doing "RESTful downloads". Here's how you can rewrite the example so that the PDF download is a part of the +show+ action, without any streaming: +While `send_data` works just fine, if you are creating a RESTful application having separate actions for file downloads is usually not necessary. In REST terminology, the PDF file from the example above can be considered just another representation of the client resource. Rails provides an easy and quite sleek way of doing "RESTful downloads". Here's how you can rewrite the example so that the PDF download is a part of the `show` action, without any streaming: ```ruby class ClientsController < ApplicationController @@ -736,7 +736,7 @@ class ClientsController < ApplicationController end ``` -In order for this example to work, you have to add the PDF MIME type to Rails. This can be done by adding the following line to the file +config/initializers/mime_types.rb+: +In order for this example to work, you have to add the PDF MIME type to Rails. This can be done by adding the following line to the file `config/initializers/mime_types.rb`: ```ruby Mime::Type.register "application/pdf", :pdf @@ -753,7 +753,7 @@ GET /clients/1.pdf Parameter Filtering ------------------- -Rails keeps a log file for each environment in the +log+ folder. These are extremely useful when debugging what's actually going on in your application, but in a live application you may not want every bit of information to be stored in the log file. You can filter certain request parameters from your log files by appending them to `config.filter_parameters` in the application configuration. These parameters will be marked [FILTERED] in the log. +Rails keeps a log file for each environment in the `log` folder. These are extremely useful when debugging what's actually going on in your application, but in a live application you may not want every bit of information to be stored in the log file. You can filter certain request parameters from your log files by appending them to `config.filter_parameters` in the application configuration. These parameters will be marked [FILTERED] in the log. ```ruby config.filter_parameters << :password @@ -762,21 +762,21 @@ config.filter_parameters << :password Rescue ------ -Most likely your application is going to contain bugs or otherwise throw an exception that needs to be handled. For example, if the user follows a link to a resource that no longer exists in the database, Active Record will throw the +ActiveRecord::RecordNotFound+ exception. +Most likely your application is going to contain bugs or otherwise throw an exception that needs to be handled. For example, if the user follows a link to a resource that no longer exists in the database, Active Record will throw the `ActiveRecord::RecordNotFound` exception. Rails' default exception handling displays a "500 Server Error" message for all exceptions. If the request was made locally, a nice traceback and some added information gets displayed so you can figure out what went wrong and deal with it. If the request was remote Rails will just display a simple "500 Server Error" message to the user, or a "404 Not Found" if there was a routing error or a record could not be found. Sometimes you might want to customize how these errors are caught and how they're displayed to the user. There are several levels of exception handling available in a Rails application: ### The Default 500 and 404 Templates -By default a production application will render either a 404 or a 500 error message. These messages are contained in static HTML files in the +public+ folder, in +404.html+ and +500.html+ respectively. You can customize these files to add some extra information and layout, but remember that they are static; i.e. you can't use RHTML or layouts in them, just plain HTML. +By default a production application will render either a 404 or a 500 error message. These messages are contained in static HTML files in the `public` folder, in `404.html` and `500.html` respectively. You can customize these files to add some extra information and layout, but remember that they are static; i.e. you can't use RHTML or layouts in them, just plain HTML. -### +rescue_from+ +### `rescue_from` -If you want to do something a bit more elaborate when catching errors, you can use +rescue_from+, which handles exceptions of a certain type (or multiple types) in an entire controller and its subclasses. +If you want to do something a bit more elaborate when catching errors, you can use `rescue_from`, which handles exceptions of a certain type (or multiple types) in an entire controller and its subclasses. -When an exception occurs which is caught by a +rescue_from+ directive, the exception object is passed to the handler. The handler can be a method or a +Proc+ object passed to the +:with+ option. You can also use a block directly instead of an explicit +Proc+ object. +When an exception occurs which is caught by a `rescue_from` directive, the exception object is passed to the handler. The handler can be a method or a `Proc` object passed to the `:with` option. You can also use a block directly instead of an explicit `Proc` object. -Here's how you can use +rescue_from+ to intercept all +ActiveRecord::RecordNotFound+ errors and do something with them. +Here's how you can use `rescue_from` to intercept all `ActiveRecord::RecordNotFound` errors and do something with them. ```ruby class ApplicationController < ActionController::Base @@ -822,12 +822,12 @@ class ClientsController < ApplicationController end ``` -NOTE: Certain exceptions are only rescuable from the +ApplicationController+ class, as they are raised before the controller gets initialized and the action gets executed. See Pratik Naik's "article":http://m.onkey.org/2008/7/20/rescue-from-dispatching on the subject for more information. +NOTE: Certain exceptions are only rescuable from the `ApplicationController` class, as they are raised before the controller gets initialized and the action gets executed. See Pratik Naik's "article":http://m.onkey.org/2008/7/20/rescue-from-dispatching on the subject for more information. Force HTTPS protocol -------------------- -Sometime you might want to force a particular controller to only be accessible via an HTTPS protocol for security reasons. Since Rails 3.1 you can now use +force_ssl+ method in your controller to enforce that: +Sometime you might want to force a particular controller to only be accessible via an HTTPS protocol for security reasons. Since Rails 3.1 you can now use `force_ssl` method in your controller to enforce that: ```ruby class DinnerController @@ -835,7 +835,7 @@ class DinnerController end ``` -Just like the filter, you could also passing +:only+ and +:except+ to enforce the secure connection only to specific actions. +Just like the filter, you could also passing `:only` and `:except` to enforce the secure connection only to specific actions. ```ruby class DinnerController @@ -845,4 +845,4 @@ class DinnerController end ``` -Please note that if you found yourself adding +force_ssl+ to many controllers, you may found yourself wanting to force the whole application to use HTTPS instead. In that case, you can set the +config.force_ssl+ in your environment file. +Please note that if you found yourself adding `force_ssl` to many controllers, you may found yourself wanting to force the whole application to use HTTPS instead. In that case, you can set the `config.force_ssl` in your environment file. |