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
TRAILER =
'trailer'
POLICY =
{
	# Headers which may only be specified once.
	'content-type' => false,
	'content-disposition' => false,
	'content-length' => false,
	'user-agent' => false,
	'referer' => false,
	'host' => 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,
	
	# Authorization headers:
	'authorization' => Header::Authorization,
	'proxy-authorization' => Header::Authorization,
	
	# 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 66

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

Instance Attribute Details

#fieldsObject (readonly)

An array of `[key, value]` pairs.


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# File 'lib/protocol/http/headers.rb', line 102

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`. If the underlying array is frozen, it will be duped.

Returns:

  • (Headers)

    an instance of headers.


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# File 'lib/protocol/http/headers.rb', line 44

def self.[] headers
	if headers.nil?
		return self.new
	end
	
	if headers.is_a?(self)
		if headers.frozen?
			return headers.dup
		else
			return headers
		end
	end
	
	fields = headers.to_a
	
	if fields.frozen?
		fields = fields.dup
	end
	
	return self.new(fields)
end

Instance Method Details

#==(other) ⇒ Object


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# File 'lib/protocol/http/headers.rb', line 314

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 297

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 210

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 182

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

#clearObject


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

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 260

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 152

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

#empty?Boolean

Returns:

  • (Boolean)

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# File 'lib/protocol/http/headers.rb', line 148

def empty?
	@fields.empty?
end

#extract(keys) ⇒ Object


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

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

#flattenObject


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# File 'lib/protocol/http/headers.rb', line 97

def flatten
	self.dup.flatten!
end

#flatten!Object

Flatten trailer into the headers.


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# File 'lib/protocol/http/headers.rb', line 88

def flatten!
	if @tail
		self.delete(TRAILER)
		@tail = nil
	end
	
	return self
end

#freezeObject


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# File 'lib/protocol/http/headers.rb', line 136

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 156

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

#initialize_dup(other) ⇒ Object


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# File 'lib/protocol/http/headers.rb', line 74

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

#inspectObject


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# File 'lib/protocol/http/headers.rb', line 310

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

#keysObject


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# File 'lib/protocol/http/headers.rb', line 160

def keys
	self.to_h.keys
end

#merge(headers) ⇒ Object


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# File 'lib/protocol/http/headers.rb', line 203

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

#merge!(headers) ⇒ Object


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# File 'lib/protocol/http/headers.rb', line 195

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 189

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

#to_hObject

A hash table of `policy.map(values)`


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# File 'lib/protocol/http/headers.rb', line 302

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

#trailer(&block) ⇒ Object

Enumerate all headers in the trailer, if there are any.


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# File 'lib/protocol/http/headers.rb', line 128

def trailer(&block)
	return to_enum(:trailer) unless block_given?
	
	if @tail
		@fields.drop(@tail).each(&block)
	end
end

#trailer!(&block) ⇒ Object

Record the current headers, and prepare to add trailers.

This method is typically used after headers are sent to capture any additional headers which should then be sent as trailers.

A sender that intends to generate one or more trailer fields in a message should generate a trailer header field in the header section of that message to indicate which fields might be present in the trailers.


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# File 'lib/protocol/http/headers.rb', line 121

def trailer!(&block)
	@tail ||= @fields.size
	
	return trailer(&block)
end

#trailer?Boolean

Returns:

  • (Boolean)

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# File 'lib/protocol/http/headers.rb', line 105

def trailer?
	@tail != nil
end