Rails中的request
每个web请求都有对应的 Request和Response，在Rails中，我们如何获取关于request的信息呢？
Request对象
在controller的实例中，可以通过request方法获取request对象
request
# => ActionDispatch::Request对象
Request对象包含的内容
Headers
request.headers
# => #<ActionDispatch::Http::Headers:0x007ff849c55a50>
headers分为：
request.headers
response.headers
Params
request.params # => ActiveSupport::HashWithIndifferentAccess对象
request.parameters # 同request.params
request.path_parameters
params 返回的是 ActionController::Parameters 对象
Method
request.method # => "GET"，String对象
request.method_symbol # => :get，Symbol对象
request.request_method_symbol
request.get?
request.post?
request.put?
request.patch?
request.delete?
request.head?
Url
request.fullpath
request.original_fullpath
request.original_url
请求内容
request.body # => StringIO对象
request.body_stream
request.raw_post
request.form_data?
request.xml_http_request?
request.authorization
MIME等信息
request.media_type
request.accepts
request.content_type
request.formats
request.format
request.variant
客户端、服务端、中间件信息
request.ip
request.remote_ip
request.local?
request.uuid
request.server_software
缓存相关信息
request.if_modified_since
request.if_none_match
request.if_none_match_etags