class ActionDispatch::Http::Headers
Provides access to the request's HTTP headers from the environment.
env = { "CONTENT_TYPE" => "text/plain", "HTTP_USER_AGENT" => "curl/7.43.0" } headers = ActionDispatch::Http::Headers.new(env) headers["Content-Type"] # => "text/plain" headers["User-Agent"] # => "curl/7.43.0"
Also note that when headers are mapped to CGI-like variables by the Rack server, both dashes and underscores are converted to underscores. This ambiguity cannot be resolved at this stage anymore. Both underscores and dashes have to be interpreted as if they were originally sent as dashes.
# GET / HTTP/1.1 # ... # User-Agent: curl/7.43.0 # X_Custom_Header: token headers["X_Custom_Header"] # => nil headers["X-Custom-Header"] # => "token"
Constants
- CGI_VARIABLES
- HTTP_HEADER
Public Class Methods
# File lib/action_dispatch/http/headers.rb, line 48 def self.from_hash(hash) new ActionDispatch::Request.new hash end
Public Instance Methods
Returns the value for the given key mapped to @env.
# File lib/action_dispatch/http/headers.rb, line 57 def [](key) @req.get_header env_name(key) end
Sets the given value for the key mapped to @env.
# File lib/action_dispatch/http/headers.rb, line 62 def []=(key, value) @req.set_header env_name(key), value end
Add a value to a multivalued header like Vary or Accept-Encoding.
# File lib/action_dispatch/http/headers.rb, line 67 def add(key, value) @req.add_header env_name(key), value end
# File lib/action_dispatch/http/headers.rb, line 93 def each(&block) @req.each_header(&block) end
# File lib/action_dispatch/http/headers.rb, line 114 def env; @req.env.dup; end
Returns the value for the given key mapped to @env.
If the key is not found and an optional code block is not provided, raises
a KeyError
exception.
If the code block is provided, then it will be run and its result returned.
# File lib/action_dispatch/http/headers.rb, line 85 def fetch(key, default = DEFAULT) @req.fetch_header(env_name(key)) do return default unless default == DEFAULT return yield if block_given? raise NameError, key end end
# File lib/action_dispatch/http/headers.rb, line 71 def key?(key) @req.has_header? env_name(key) end
Returns a new Http::Headers instance containing
the contents of headers_or_env
and the original instance.
# File lib/action_dispatch/http/headers.rb, line 99 def merge(headers_or_env) headers = @req.dup.headers headers.merge!(headers_or_env) headers end
Adds the contents of headers_or_env
to original instance
entries; duplicate keys are overwritten with the values from
headers_or_env
.
# File lib/action_dispatch/http/headers.rb, line 108 def merge!(headers_or_env) headers_or_env.each do |key, value| @req.set_header env_name(key), value end end
Private Instance Methods
Converts an HTTP header name to an environment variable name if it is not contained within the headers hash.
# File lib/action_dispatch/http/headers.rb, line 120 def env_name(key) key = key.to_s if key =~ HTTP_HEADER key = key.upcase.tr('-', '_') key = "HTTP_" + key unless CGI_VARIABLES.include?(key) end key end