Class: ActionDispatch::Http::Headers

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Instance Chain: self, `::Enumerable`, `::ActiveSupport::EnumerableCoreExt::Constants`
Inherits:	Object
Defined in:	actionpack/lib/action_dispatch/http/headers.rb

Overview

Action Dispatch 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.from_hash(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"

Constant Summary

CGI_VARIABLES =
# File 'actionpack/lib/action_dispatch/http/headers.rb', line 29

Set.new(%W[
  AUTH_TYPE
  CONTENT_LENGTH
  CONTENT_TYPE
  GATEWAY_INTERFACE
  HTTPS
  PATH_INFO
  PATH_TRANSLATED
  QUERY_STRING
  REMOTE_ADDR
  REMOTE_HOST
  REMOTE_IDENT
  REMOTE_USER
  REQUEST_METHOD
  SCRIPT_NAME
  SERVER_NAME
  SERVER_PORT
  SERVER_PROTOCOL
  SERVER_SOFTWARE
]).freeze

DEFAULT = Internal use only
# File 'actionpack/lib/action_dispatch/http/headers.rb', line 82
```
Object.new
```
HTTP_HEADER =
# File 'actionpack/lib/action_dispatch/http/headers.rb', line 50
```
/\A[A-Za-z0-9-]+\z/
```

Class Method Summary

.from_hash(hash)
.new(request) ⇒ Headers constructor Internal use only

Instance Attribute Summary

`::Enumerable` - Included

#many?

Returns true if the enumerable has more than 1 element.

Instance Method Summary

#[](key)

Returns the value for the given key mapped to @env.
#[]=(key, value)

Sets the given value for the key mapped to @env.
#add(key, value)

Add a value to a multivalued header like Vary or Accept-Encoding.
#each(&block)
#env
#fetch(key, default = DEFAULT)

Returns the value for the given key mapped to @env.
#include?(key)

Alias for #key?.
#key?(key) ⇒ Boolean (also: #include?)
#merge(headers_or_env)

Returns a new Headers instance containing the contents of headers_or_env and the original instance.
#merge!(headers_or_env)

Adds the contents of headers_or_env to original instance entries; duplicate keys are overwritten with the values from headers_or_env.
#env_name(key) private

Converts an HTTP header name to an environment variable name if it is not contained within the headers hash.

`::Enumerable` - Included

#compact_blank	Returns a new `::Array` without the blank items.
#exclude?	The negative of the `Enumerable#include?`.
#excluding	Returns a copy of the enumerable excluding the specified elements.
#in_order_of	Returns a new `::Array` where the order has been set to that provided in the `series`, based on the `key` of the objects in the original enumerable.
#including	Returns a new array that includes the passed elements.
#index_by	Convert an enumerable to a hash, using the block result as the key and the element as the value.
#index_with	Convert an enumerable to a hash, using the element as the key and the block result as the value.
#maximum	Calculates the maximum from the extracted elements.
#minimum	Calculates the minimum from the extracted elements.
#pick	Extract the given key from the first element in the enumerable.
#pluck	Extract the given key from each element in the enumerable.
#sole	Returns the sole item in the enumerable.
#without	Alias for Enumerable#excluding.
#as_json

`::ActiveSupport::EnumerableCoreExt::Constants` - Included

#const_missing

Constructor Details

.new(request) ⇒ `Headers`

This method is for internal use only.

[ GitHub ]

# File 'actionpack/lib/action_dispatch/http/headers.rb', line 58


def initialize(request) # :nodoc:
  @req = request
end

Class Method Details

.from_hash(hash)

[ GitHub ]

# File 'actionpack/lib/action_dispatch/http/headers.rb', line 54


def self.from_hash(hash)
  new ActionDispatch::Request.new hash
end

Instance Method Details

#[](key)

Returns the value for the given key mapped to @env.

[ GitHub ]

# File 'actionpack/lib/action_dispatch/http/headers.rb', line 63


def [](key)
  @req.get_header env_name(key)
end

#[]=(key, value)

Sets the given value for the key mapped to @env.

[ GitHub ]

# File 'actionpack/lib/action_dispatch/http/headers.rb', line 68


def []=(key, value)
  @req.set_header env_name(key), value
end

#add(key, value)

Add a value to a multivalued header like Vary or Accept-Encoding.

[ GitHub ]

# File 'actionpack/lib/action_dispatch/http/headers.rb', line 73


def add(key, value)
  @req.add_header env_name(key), value
end

#each(&block)

[ GitHub ]

# File 'actionpack/lib/action_dispatch/http/headers.rb', line 98


def each(&block)
  @req.each_header(&block)
end

#env

[ GitHub ]

# File 'actionpack/lib/action_dispatch/http/headers.rb', line 118


def env; @req.env.dup; end

#env_name(key) (private)

Converts an HTTP header name to an environment variable name if it is not contained within the headers hash.

[ GitHub ]

# File 'actionpack/lib/action_dispatch/http/headers.rb', line 123


def env_name(key)
  key = key.to_s
  if HTTP_HEADER.match?(key)
    key = key.upcase
    key.tr!("-", "_")
    key.prepend("HTTP_") unless CGI_VARIABLES.include?(key)
  end
  key
end

#fetch(key, default = DEFAULT)

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.

[ GitHub ]

# File 'actionpack/lib/action_dispatch/http/headers.rb', line 90


def fetch(key, default = DEFAULT)
  @req.fetch_header(env_name(key)) do
    return default unless default == DEFAULT
    return yield if block_given?
    raise KeyError, key
  end
end

#include?(key)

Alias for #key?.

[ GitHub ]

# File 'actionpack/lib/action_dispatch/http/headers.rb', line 80


alias :include? :key?

#key?(key) ⇒ `Boolean` Also known as: #include?

[ GitHub ]

# File 'actionpack/lib/action_dispatch/http/headers.rb', line 77


def key?(key)
  @req.has_header? env_name(key)
end

#merge(headers_or_env)

Returns a new Headers instance containing the contents of headers_or_env and the original instance.

[ GitHub ]

# File 'actionpack/lib/action_dispatch/http/headers.rb', line 104


def merge(headers_or_env)
  headers = @req.dup.headers
  headers.merge!(headers_or_env)
  headers
end

#merge!(headers_or_env)

Adds the contents of headers_or_env to original instance entries; duplicate keys are overwritten with the values from headers_or_env.

[ GitHub ]

# File 'actionpack/lib/action_dispatch/http/headers.rb', line 112


def merge!(headers_or_env)
  headers_or_env.each do |key, value|
    @req.set_header env_name(key), value
  end
end

Class: ActionDispatch::Http::Headers

Overview

Action Dispatch HTTP Headers

Constant Summary

Class Method Summary

Instance Attribute Summary

::Enumerable - Included

Instance Method Summary

::Enumerable - Included

::ActiveSupport::EnumerableCoreExt::Constants - Included

Constructor Details

.new(request) ⇒ Headers

Class Method Details

.from_hash(hash)

Instance Method Details

#[](key)

#[]=(key, value)

#add(key, value)

#each(&block)

#env

#env_name(key) (private)

#fetch(key, default = DEFAULT)

#include?(key)

#key?(key) ⇒ Boolean Also known as: #include?

#merge(headers_or_env)

#merge!(headers_or_env)

`::Enumerable` - Included

`::Enumerable` - Included

`::ActiveSupport::EnumerableCoreExt::Constants` - Included

.new(request) ⇒ `Headers`

#key?(key) ⇒ `Boolean` Also known as: #include?