Ruby-on-rails Rails 3 respond_to：默认格式？
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Rails 3 respond_to: default format?
提问by bdorry
I am converting a Rails 2 application to Rails 3. I currently have a controller set up like the following:
我正在将 Rails 2 应用程序转换为 Rails 3。我目前有一个控制器设置如下：
class Api::RegionsController < ApplicationController
respond_to :xml, :json
end
with and an action that looks like the following:
和一个如下所示的动作：
def index
@regions = Region.all
respond_with @regions
end
The implementation is pretty straightforward, api/regions, api/regions.xml and api/regions.json all respond as you would expect. The problem is that I want api/regions by default to respond via XML. I have consumers that expect an XML response and I would hate to have them change all their URLs to include .xml unless absolutely necessary.
实现非常简单，api/regions、api/regions.xml 和 api/regions.json 都按您的预期响应。问题是我希望 api/regions 默认通过 XML 响应。我有消费者希望得到 XML 响应，除非绝对必要，否则我不想让他们更改所有 URL 以包含 .xml。
In Rails 2 you would accomplish that by doing this:
在 Rails 2 中，您可以通过执行以下操作来实现：
respond_to do |format|
format.xml { render :xml => @region.to_xml }
format.json { render :json => @region.to_json }
end
But in Rails 3 I cannot find a way to default it to an XML response. Any ideas?
但是在 Rails 3 中，我找不到将其默认为 XML 响应的方法。有任何想法吗？
回答by Mike Clymer
If I understand what you are trying to do, you probably can solve the issue by setting the default resource format to XML. This will allow your users to make requests using 'api/regions' and have the response default to XML. Take a look at look at the 'Controller Namespaces and Routing' and the 'Defining Defaults' sections at:
如果我明白您要做什么，您可能可以通过将默认资源格式设置为 XML 来解决问题。这将允许您的用户使用“api/regions”发出请求，并将响应默认为 XML。查看“控制器命名空间和路由”和“定义默认值”部分：
http://guides.rubyonrails.org/routing.html
http://guides.rubyonrails.org/routing.html
You could do something like the following in routes.rb:
您可以在 routes.rb 中执行以下操作：
namespace "api" do
resources :regions, :defaults => { :format => 'xml' }
end
Then you should be able to have the following work for your controller methods:
那么你应该能够为你的控制器方法做以下工作：
class Api::RegionsController < ApplicationController
respond_to :xml, :json
def index
respond_with(@regions = Region.all)
end
end
回答by clacke
I have been fighting this issue today, and I settled for the before_filtersolution you mentioned yourself in your comment:
我今天一直在与这个问题作斗争，我决定采用before_filter您在评论中提到的解决方案：
before_filter :default_format_xml
# Set format to xml unless client requires a specific format
# Works on Rails 3.0.9
def default_format_xml
request.format = "xml" unless params[:format]
end
This solution also allows for taking into account content negotiation, which was a factor in my case. I wanted web browsers to get an HTML view but custom clients (with no Accept headers) to get JSON. This solved my problem:
该解决方案还允许考虑内容协商，这在我的案例中是一个因素。我希望 Web 浏览器获得 HTML 视图，但自定义客户端（没有 Accept 标头）获得 JSON。这解决了我的问题：
before_filter :default_format_json
def default_format_json
if(request.headers["HTTP_ACCEPT"].nil? &&
params[:format].nil?)
request.format = "json"
end
end
回答by Heikki
Not what you're after but related:
不是你所追求的，而是相关的：
def index
@regions = Region.all
respond_to do |format|
format.json { render :json => @regions }
format.any(:xml, :html) { render :xml => @regions }
end
end
"Respond to also allows you to specify a common block for different formats by using any"
“响应还允许您使用 any 为不同格式指定一个公共块”
回答by Малъ Скрылевъ
Well, as you have been noted that each format should be explicitly rendered with specific render call, you can also avoid any request with unknown or unsupported format, for my example called default, as follows:
好吧，正如您已经注意到的，每种格式都应该使用特定的渲染调用显式渲染，您还可以避免任何格式未知或不受支持的请求，例如我的示例default，如下所示：
rescue_from ActionController::UnknownFormat, with: ->{ render nothing: true }
You can simulate the unknown format call with the simple browser (exmp.firefox) line (in development mode):
您可以使用简单的浏览器 (exmp.firefox) 行（在开发模式下）模拟未知格式的调用：
http://localhost/index.default
It will call :indexmethod of a root controller with format called as default.
它将调用:index根控制器的方法，格式为default。
回答by buru
An easy but ugly solution is to override html content type handling to render xml:
一个简单但丑陋的解决方案是覆盖 html 内容类型处理以呈现 xml：
respond_to :html, :xml, :json
def index
@regions = Region.all
respond_with @regions do |format|
format.html { render :xml => @regions }
end
end
