300 Multiple Choices
The HTTP 300 Multiple Choices redirection response status code indicates that the request has more than one possible response.
The user-agent or the user should choose one of them.
Note:
In agent-driven content negotiation, a client and server collaboratively decide the best variant of a given resource when the server has multiple variants.
Most clients lack a method for automatically choosing from responses, and the additional round-trips slow down client-server interaction.
Server-driven content negotiation is far more common, where a server chooses the most appropriate resource for the client based on the request headers (Accept-Language, Accept, etc.).
The server should include content in the response that contains a list of resource metadata and URIs from which the user or user agent can choose. The format of the content is implementation-specific, but should be easily parsed by the user agent (such as HTML or JSON).
If the server has a preferred choice that the client should request, it can include it in a Location header.
Status
300 Multiple Choices
Examples
300 response with list of resources
The following example demonstrates a Transparent Content Negotiation request-response exchange.
An Apache server offers multiple variants of a resource defined in a type map; index.html.en for a resource in English, and index.html.fr for a French version:
URI: index.html.en Content-Language: en URI: index.html.fr Content-Language: fr
A Negotiate: trans request header indicates that the client wants to use TCN to choose a resource.
Poor browser support for this mechanism means a user agent such as curl must be used instead:
curl -v -H "Negotiate: trans" http://localhost/index
This produces the following request:
GET /index HTTP/1.1
Host: localhost
User-Agent: curl/8.7.1
Accept: */*
Negotiate: trans
We receive a 300 response with details of different representations of the requested resource:
HTTP/1.1 300 Multiple Choices
Date: Fri, 30 Aug 2024 09:21:48 GMT
Server: Apache/2.4.59 (Unix)
Alternates: {"index.html.en" 1 {type text/html} {language en} {length 48}}, {"index.html.fr" 1 {type text/html} {language fr} {length 45}}
Vary: negotiate,accept-language
TCN: list
Content-Length: 419
Content-Type: text/html; charset=iso-8859-1
<html><head>
<title>300 Multiple Choices</title>
</head><body>
<h1>Multiple Choices</h1>
Available variants:
<ul>
<li><a href="index.html.en">index.html.en</a> , type text/html, language en</li>
<li><a href="index.html.fr">index.html.fr</a> , type text/html, language fr</li>
</ul>
</body></html>
Specifications
| Specification |
|---|
| HTTP Semantics # status.300 |