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Diffstat (limited to 'guides/source/api_app.md')
| -rw-r--r-- | guides/source/api_app.md | 96 |
1 files changed, 48 insertions, 48 deletions
diff --git a/guides/source/api_app.md b/guides/source/api_app.md index 29ca872254..64b6bb64f2 100644 --- a/guides/source/api_app.md +++ b/guides/source/api_app.md @@ -8,7 +8,7 @@ In this guide you will learn: * What Rails provides for API-only applications * How to configure Rails to start without any browser features -* How to decide which middlewares you will want to include +* How to decide which middleware you will want to include * How to decide which modules to use in your controller -------------------------------------------------------------------------------- @@ -44,11 +44,11 @@ using Rails is: "isn't using Rails to spit out some JSON overkill? Shouldn't I just use something like Sinatra?". For very simple APIs, this may be true. However, even in very HTML-heavy -applications, most of an application's logic is actually outside of the view +applications, most of an application's logic lives outside of the view layer. The reason most people use Rails is that it provides a set of defaults that -allows us to get up and running quickly without having to make a lot of trivial +allows developers to get up and running quickly, without having to make a lot of trivial decisions. Let's take a look at some of the things that Rails provides out of the box that are @@ -86,7 +86,7 @@ Handled at the middleware layer: and return just the headers on the way out. This makes `HEAD` work reliably in all Rails APIs. -While you could obviously build these up in terms of existing Rack middlewares, +While you could obviously build these up in terms of existing Rack middleware, this list demonstrates that the default Rails middleware stack provides a lot of value, even if you're "just generating JSON". @@ -97,7 +97,7 @@ Handled at the Action Pack layer: means not having to spend time thinking about how to model your API in terms of HTTP. - URL Generation: The flip side of routing is URL generation. A good API based - on HTTP includes URLs (see [the GitHub gist API](http://developer.github.com/v3/gists/) + on HTTP includes URLs (see [the GitHub Gist API](http://developer.github.com/v3/gists/) for an example). - Header and Redirection Responses: `head :no_content` and `redirect_to user_url(current_user)` come in handy. Sure, you could manually @@ -126,7 +126,7 @@ when configuring Active Record. **The short version is**: you may not have thought about which parts of Rails are still applicable even if you remove the view layer, but the answer turns out -to be "most of it". +to be most of it. The Basic Configuration ----------------------- @@ -143,11 +143,11 @@ $ rails new my_api --api This will do three main things for you: -- Configure your application to start with a more limited set of middlewares +- Configure your application to start with a more limited set of middleware than normal. Specifically, it will not include any middleware primarily useful for browser applications (like cookies support) by default. - Make `ApplicationController` inherit from `ActionController::API` instead of - `ActionController::Base`. As with middlewares, this will leave out any Action + `ActionController::Base`. As with middleware, this will leave out any Action Controller modules that provide functionalities primarily used by browser applications. - Configure the generators to skip generating views, helpers and assets when @@ -163,6 +163,14 @@ class definition: config.api_only = true ``` +Optionally, in `config/environments/development.rb` add the following line +to render error responses using the API format (JSON by default) when it +is a local request: + +```ruby +config.debug_exception_response_format = :api +``` + Finally, inside `app/controllers/application_controller.rb`, instead of: ```ruby @@ -177,39 +185,38 @@ class ApplicationController < ActionController::API end ``` -Choosing Middlewares +Choosing Middleware -------------------- -An API application comes with the following middlewares by default: +An API application comes with the following middleware by default: - `Rack::Sendfile` - `ActionDispatch::Static` -- `Rack::Lock` +- `ActionDispatch::LoadInterlock` - `ActiveSupport::Cache::Strategy::LocalCache::Middleware` +- `Rack::Runtime` - `ActionDispatch::RequestId` - `Rails::Rack::Logger` -- `Rack::Runtime` - `ActionDispatch::ShowExceptions` - `ActionDispatch::DebugExceptions` - `ActionDispatch::RemoteIp` - `ActionDispatch::Reloader` - `ActionDispatch::Callbacks` -- `ActionDispatch::ParamsParser` - `Rack::Head` - `Rack::ConditionalGet` - `Rack::ETag` -See the [internal middlewares](rails_on_rack.html#internal-middleware-stack) +See the [internal middleware](rails_on_rack.html#internal-middleware-stack) section of the Rack guide for further information on them. -Other plugins, including Active Record, may add additional middlewares. In -general, these middlewares are agnostic to the type of application you are +Other plugins, including Active Record, may add additional middleware. In +general, these middleware are agnostic to the type of application you are building, and make sense in an API-only Rails application. -You can get a list of all middlewares in your application via: +You can get a list of all middleware in your application via: ```bash -$ rake middleware +$ rails middleware ``` ### Using the Cache Middleware @@ -222,7 +229,7 @@ For instance, using the `stale?` method: ```ruby def show - @post = Post.find(params[:id]) + @post = Post.find(params[:id]) if stale?(last_modified: @post.updated_at) render json: @post @@ -241,7 +248,7 @@ cross-client caching in the call to `stale?`: ```ruby def show - @post = Post.find(params[:id]) + @post = Post.find(params[:id]) if stale?(last_modified: @post.updated_at, public: true) render json: @post @@ -255,9 +262,6 @@ subsequent inbound requests for the same URL. Think of it as page caching using HTTP semantics. -NOTE: This middleware is always outside of the `Rack::Lock` mutex, even in -single-threaded applications. - ### Using Rack::Sendfile When you use the `send_file` method inside a Rails controller, it sets the @@ -289,12 +293,9 @@ config.action_dispatch.x_sendfile_header = "X-Accel-Redirect" Make sure to configure your server to support these options following the instructions in the `Rack::Sendfile` documentation. -NOTE: The `Rack::Sendfile` middleware is always outside of the `Rack::Lock` -mutex, even in single-threaded applications. +### Using ActionDispatch::Request -### Using ActionDispatch::ParamsParser - -`ActionDispatch::ParamsParser` will take parameters from the client in the JSON +`ActionDispatch::Request#params` will take parameters from the client in the JSON format and make them available in your controller inside `params`. To use this, your client will need to make a request with JSON-encoded parameters @@ -313,16 +314,16 @@ jQuery.ajax({ }); ``` -`ActionDispatch::ParamsParser` will see the `Content-Type` and your parameters +`ActionDispatch::Request` will see the `Content-Type` and your parameters will be: ```ruby { :person => { :firstName => "Yehuda", :lastName => "Katz" } } ``` -### Other Middlewares +### Other Middleware -Rails ships with a number of other middlewares that you might want to use in an +Rails ships with a number of other middleware that you might want to use in an API application, especially if one of your API clients is the browser: - `Rack::MethodOverride` @@ -333,13 +334,13 @@ API application, especially if one of your API clients is the browser: * `ActionDispatch::Session::CookieStore` * `ActionDispatch::Session::MemCacheStore` -Any of these middlewares can be added via: +Any of these middleware can be added via: ```ruby config.middleware.use Rack::MethodOverride ``` -### Removing Middlewares +### Removing Middleware If you don't want to use a middleware that is included by default in the API-only middleware set, you can remove it with: @@ -348,7 +349,7 @@ middleware set, you can remove it with: config.middleware.delete ::Rack::Sendfile ``` -Keep in mind that removing these middlewares will remove support for certain +Keep in mind that removing these middleware will remove support for certain features in Action Controller. Choosing Controller Modules @@ -357,25 +358,24 @@ Choosing Controller Modules An API application (using `ActionController::API`) comes with the following controller modules by default: -- `ActionController::UrlFor`: Makes `url_for` and friends available. +- `ActionController::UrlFor`: Makes `url_for` and similar helpers available. - `ActionController::Redirecting`: Support for `redirect_to`. -- `ActionController::Rendering`: Basic support for rendering. +- `AbstractController::Rendering` and `ActionController::ApiRendering`: Basic support for rendering. - `ActionController::Renderers::All`: Support for `render :json` and friends. - `ActionController::ConditionalGet`: Support for `stale?`. -- `ActionController::ForceSSL`: Support for `force_ssl`. -- `ActionController::RackDelegation`: Support for the `request` and `response` - methods returning `ActionDispatch::Request` and `ActionDispatch::Response` - objects. -- `ActionController::DataStreaming`: Support for `send_file` and `send_data`. -- `AbstractController::Callbacks`: Support for `before_filter` and friends. -- `ActionController::Instrumentation`: Support for the instrumentation - hooks defined by Action Controller (see [the instrumentation - guide](active_support_instrumentation.html#action-controller)). -- `ActionController::Rescue`: Support for `rescue_from`. - `ActionController::BasicImplicitRender`: Makes sure to return an empty response if there's not an explicit one. - `ActionController::StrongParameters`: Support for parameters white-listing in combination with Active Model mass assignment. +- `ActionController::ForceSSL`: Support for `force_ssl`. +- `ActionController::DataStreaming`: Support for `send_file` and `send_data`. +- `AbstractController::Callbacks`: Support for `before_action` and + similar helpers. +- `ActionController::Rescue`: Support for `rescue_from`. +- `ActionController::Instrumentation`: Support for the instrumentation + hooks defined by Action Controller (see [the instrumentation + guide](active_support_instrumentation.html#action-controller) for +more information regarding this). - `ActionController::ParamsWrapper`: Wraps the parameters hash into a nested hash so you don't have to specify root elements sending POST requests for instance. @@ -397,12 +397,12 @@ Some common modules you might want to add: - `AbstractController::Translation`: Support for the `l` and `t` localization and translation methods. -- `ActionController::HTTPAuthentication::Basic` (or `Digest` or `Token`): Support +- `ActionController::HttpAuthentication::Basic` (or `Digest` or `Token`): Support for basic, digest or token HTTP authentication. - `AbstractController::Layouts`: Support for layouts when rendering. - `ActionController::MimeResponds`: Support for `respond_to`. - `ActionController::Cookies`: Support for `cookies`, which includes support for signed and encrypted cookies. This requires the cookies middleware. -The best place to add a module is in your `ApplicationController` but you can +The best place to add a module is in your `ApplicationController`, but you can also add modules to individual controllers. |