# Mime Negotiation

在 new 页面，对 <http://blog.test.example.com:3000/users> 发起 POST 请求。

检测结果：

```ruby
request.accepts
=> [#<Mime::Type:0x007f8a1a498cd8 @string="text/html", @symbol=:html, \n
                                  @synonyms=["application/xhtml+xml"]>,
 #<Mime::Type:0x007f8a20f2f498 @string="image/webp", @symbol=nil, @synonyms=[]>,
 #<Mime::Type:0x007f8a1a48a908 @string="application/xml", @symbol=:xml, \n
                               @synonyms=["text/xml", "application/x-xml"]>,
 #<Mime::Type:0x007f8a20f2f3f8 @string="*/*", @symbol=nil, @synonyms=[]>]

request.content_mime_type
=> #<Mime::Type:0x007f8a1a47be58 @string="application/x-www-form-urlencoded", \n
                                 @symbol=:url_encoded_form, @synonyms=[]>

request.content_type
=> "application/x-www-form-urlencoded"

# = formats.first
request.format
=> #<Mime::Type:0x007f8a1a498cd8 @string="text/html", @symbol=:html, \n
                                 @synonyms=["application/xhtml+xml"]>

request.formats
=> [#<Mime::Type:0x007f8a1a498cd8 @string="text/html", @symbol=:html, \n
                                  @synonyms=["application/xhtml+xml"]>]
```

除上述方法外，还有：

```
negotiate_mime

format=
formats=
variant=
```

给“变种”增加了一些新的方法：

```ruby
request.variant = :phone
request.variant.phone?  # true
request.variant.tablet? # false

request.variant = [:phone, :tablet]
request.variant.phone?                  # true
request.variant.desktop?                # false
request.variant.any?(:phone, :desktop)  # true
request.variant.any?(:desktop, :watch)  # false
```


---

# Agent Instructions: Querying This Documentation

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Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://kelby.gitbook.io/rails-beginner-s-guide/actiondispatch_http/actiondispatch_request/http_mimenegotiation.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.