HTTP状态码300（多选）的确切响应结构是什么？(What is the exact response structure for HTTP status code 300 (Multiple Choices)?)

 当用户点击我的网站http://mysite.com/some-drawing上的图形链接时，我希望我的服务器响应状态码300和两个资源位置： http://mysite.com/some-drawing.png : http://mysite.com/some-drawing.png和http://mysite.com/some-drawing.myapp ，并让客户端浏览器根据其功能自动决定使用哪一个： 
 
 
 
 如果MyApp安装在用户的机器上，那么浏览器应该下载*.myapp版本并使用MyApp来显示它。 
 
 
 但是，如果未安装MyApp，且浏览器无法显示此版本，那么我希望它选择*.png版本。 
 
 
 但是，我很难搞清楚状态码为300的HTTP响应的结构。 
 
 rfc2616说： 
 
 
 
 所请求的资源对应于一组表示中的任何一个，每个表示具有其自己的特定位置，并且正在提供代理驱动的协商信息（第12节），以便用户（或用户代理）可以选择优先表示并将其重定向请求到该位置。 
 
 
 除非是HEAD请求，否则响应应该包含一个实体，该实体包含资源特征和位置列表，用户或用户代理可以从中选择最合适的资源特征和位置。 实体格式由Content-Type头部字段中给出的媒体类型指定。 根据用户代理的格式和功能，可以自动选择最合适的选项。 但是，本规范没有为这种自动选择定义任何标准。 
 
 
 如果服务器有一个首选的表示形式，它应该在位置字段中包含该表示的特定URI; 用户代理可以使用位置字段值进行自动重定向。 除非另有说明，否则此响应可缓存。 
 
 
 措辞“ 包含资源特征和位置清单的实体 ”似乎不明确。 这是什么意思？ 有人知道这是怎么完成的吗？ 

When a user clicks a link to a drawing on my site http://mysite.com/some-drawing, I would like my server to respond with status code 300 and two resource locations: http://mysite.com/some-drawing.png and http://mysite.com/some-drawing.myapp, and have the client browser decide automatically which one to use, based on its capabilities:
 
 
 
If MyApp is installed on the user's machine, then the browser should download the *.myapp version and use MyApp to display it.
 
 
However, if MyApp is not installed, and the browser is incapable to display this version, then I would like it to pick the *.png version. 
 
 
However, I am having a hard time figuring out the structure of a HTTP response with status code 300.
 
The rfc2616 says:
 
 
 
The requested resource corresponds to any one of a set of representations, each with its own specific location, and agent- driven negotiation information (section 12) is being provided so that the user (or user agent) can select a preferred representation and redirect its request to that location.
 
 
Unless it was a HEAD request, the response SHOULD include an entity containing a list of resource characteristics and location(s) from which the user or user agent can choose the one most appropriate. The entity format is specified by the media type given in the Content- Type header field. Depending upon the format and the capabilities of the user agent, selection of the most appropriate choice MAY be performed automatically. However, this specification does not define any standard for such automatic selection.
 
 
If the server has a preferred choice of representation, it SHOULD include the specific URI for that representation in the Location field; user agents MAY use the Location field value for automatic redirection. This response is cacheable unless indicated otherwise.
 
 
The wording "entity containing a list of resource characteristics and location(s)" seems ambiguous. What does it mean? Does anybody know how this is done?

原文：https://stackoverflow.com/questions/8905545