Class: Protocol::HTTP::Headers

Inherits:
Object
  • Object
show all
Defined in:
lib/protocol/http/headers.rb

Overview

Headers are an array of key-value pairs. Some header keys represent multiple values.

Defined Under Namespace

Classes: Merged

Constant Summary collapse

Split = 
Header::Split
Multiple = 
Header::Multiple
TRAILERS = 
'trailers'
POLICY = 
{
	# Headers which may only be specified once.
	'content-type' => false,
	'content-disposition' => false,
	'content-length' => false,
	'user-agent' => false,
	'referer' => false,
	'host' => false,
	'authorization' => false,
	'proxy-authorization' => false,
	'if-modified-since' => false,
	'if-unmodified-since' => false,
	'from' => false,
	'location' => false,
	'max-forwards' => false,
	
	# Custom headers:
	'connection' => Header::Connection,
	'cache-control' => Header::CacheControl,
	'vary' => Header::Vary,
	
	# Headers specifically for proxies:
	'via' => Split,
	'x-forwarded-for' => Split,
	
	# Cache validations:
	'etag' => Header::ETag,
	'if-match' => Header::ETags,
	'if-none-match' => Header::ETags,
	
	# Headers which may be specified multiple times, but which can't be concatenated:
	'www-authenticate' => Multiple,
	'proxy-authenticate' => Multiple,
	
	# Custom headers:
	'set-cookie' => Header::SetCookie,
	'cookie' => Header::Cookie,
}.tap{|hash| hash.default = Split}

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(fields = [], indexed = nil) ⇒ Headers

Returns a new instance of Headers.



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# File 'lib/protocol/http/headers.rb', line 50

def initialize(fields = [], indexed = nil)
	@fields = fields
	@indexed = indexed
	
	# Marks where trailers start in the @fields array.
	@tail = nil
end

Instance Attribute Details

#fields ⇒ Object (readonly)

An array of ‘[key, value]` pairs.



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

def fields
  @fields
end

Class Method Details

.[](headers) ⇒ Headers

Construct an instance from a headers Array or Hash. No-op if already an instance of ‘Headers`.

Returns:

  • (Headers) —

    an instance of headers.



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# File 'lib/protocol/http/headers.rb', line 42

def self.[] headers
	if headers.is_a?(self)
		headers
	else
		self.new(headers.to_a)
	end
end

Instance Method Details

#==(other) ⇒ Object 



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# File 'lib/protocol/http/headers.rb', line 273

def == other
	case other
	when Hash
		to_h == other
	when Headers
		@fields == other.fields
	else
		@fields == other
	end
end

#[](key) ⇒ Object 



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# File 'lib/protocol/http/headers.rb', line 256

def [] key
	to_h[key]
end

#[]=(key, value) ⇒ Object

Append the value to the given key. Some values can be appended multiple times, others can only be set once.

Parameters:

  • key (String) —

    The header key.

  • value —

    The header value.



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# File 'lib/protocol/http/headers.rb', line 171

def []= key, value
	if @indexed
		merge_into(@indexed, key.downcase, value)
	end
	
	@fields << [key, value]
end

#add(key, value) ⇒ Object

Add the specified header key value pair.

Parameters:

  • key (String) —

    the header key.

  • value (String) —

    the header value to assign.



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# File 'lib/protocol/http/headers.rb', line 143

def add(key, value)
	self[key] = value
end

#clear ⇒ Object 



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# File 'lib/protocol/http/headers.rb', line 66

def clear
	@fields.clear
	@indexed = nil
	@tail = nil
end

#delete(key) ⇒ Object

Delete all headers with the given key, and return the merged value.



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# File 'lib/protocol/http/headers.rb', line 219

def delete(key)
	deleted, @fields = @fields.partition do |field|
		field.first.downcase == key
	end
	
	if deleted.empty?
		return nil
	end
	
	if @indexed
		return @indexed.delete(key)
	elsif policy = POLICY[key]
		(key, value), *tail = deleted
		merged = policy.new(value)
		
		tail.each{|k,v| merged << v}
		
		return merged
	else
		key, value = deleted.last
		return value
	end
end

#each(&block) ⇒ Object 



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# File 'lib/protocol/http/headers.rb', line 114

def each(&block)
	@fields.each(&block)
end

#empty? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/protocol/http/headers.rb', line 110

def empty?
	@fields.empty?
end

#extract(keys) ⇒ Object 



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# File 'lib/protocol/http/headers.rb', line 126

def extract(keys)
	deleted, @fields = @fields.partition do |field|
		keys.include?(field.first.downcase)
	end
	
	if @indexed
		keys.each do |key|
			@indexed.delete(key)
		end
	end
	
	return deleted
end

#freeze ⇒ Object 



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

def freeze
	return if frozen?
	
	# Ensure @indexed is generated:
	self.to_h
	
	@fields.freeze
	@indexed.freeze
	
	super
end

#include?(key) ⇒ Boolean

Returns:

  • (Boolean) 


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

def include? key
	self[key] != nil
end

#initialize_dup(other) ⇒ Object 



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

def initialize_dup(other)
	super
	
	@fields = @fields.dup
	@indexed = @indexed.dup
	@tail = nil
end

#inspect ⇒ Object 



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# File 'lib/protocol/http/headers.rb', line 269

def inspect
	"#<#{self.class} #{@fields.inspect}>"
end

#keys ⇒ Object 



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# File 'lib/protocol/http/headers.rb', line 122

def keys
	self.to_h.keys
end

#merge(headers) ⇒ Object 



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# File 'lib/protocol/http/headers.rb', line 164

def merge(headers)
	self.dup.merge!(headers)
end

#merge!(headers) ⇒ Object 



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# File 'lib/protocol/http/headers.rb', line 156

def merge!(headers)
	headers.each do |key, value|
		self[key] = value
	end
	
	return self
end

#set(key, value) ⇒ Object

Set the specified header key to the specified value, replacing any existing header keys with the same name.

Parameters:

  • key (String) —

    the header key to replace.

  • value (String) —

    the header value to assign.



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# File 'lib/protocol/http/headers.rb', line 150

def set(key, value)
	# TODO This could be a bit more efficient:
	self.delete(key)
	self.add(key, value)
end

#to_h ⇒ Object

A hash table of ‘policy.map(values)`



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# File 'lib/protocol/http/headers.rb', line 261

def to_h
	@indexed ||= @fields.inject({}) do |hash, (key, value)|
		merge_into(hash, key.downcase, value)
		
		hash
	end
end

#trailers(&block) ⇒ Object

Enumerate all trailers, including evaluating all deferred headers.



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# File 'lib/protocol/http/headers.rb', line 86

def trailers(&block)
	return nil unless self.include?(TRAILERS)
	
	trailers!
	
	return to_enum(:trailers) unless block_given?
	
	if @tail
		@fields.drop(@tail).each(&block)
	end
end

#trailers! ⇒ Object

Mark the subsequent headers as trailers.



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# File 'lib/protocol/http/headers.rb', line 76

def trailers!
	@tail ||= @fields.size
end

#trailers? ⇒ Boolean

Returns the trailers if there are any.

Returns:

  • (Boolean) —

    the trailers if there are any.



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# File 'lib/protocol/http/headers.rb', line 81

def trailers?
	@tail != nil
end