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 49

def initialize(fields = [], indexed = nil)
  @fields = fields
  @indexed = indexed
  
  # Marks where trailer 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 85

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 27

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 299

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 282

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 195

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 167

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

#clear ⇒ Object 



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# File 'lib/protocol/http/headers.rb', line 64

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 245

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 135

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

#empty? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/protocol/http/headers.rb', line 131

def empty?
  @fields.empty?
end

#extract(keys) ⇒ Object 



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# File 'lib/protocol/http/headers.rb', line 149

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

#flatten ⇒ Object 



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

def flatten
  self.dup.flatten!
end

#flatten! ⇒ Object

Flatten trailer into the headers.



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# File 'lib/protocol/http/headers.rb', line 71

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

#freeze ⇒ Object 



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# File 'lib/protocol/http/headers.rb', line 119

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

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

Returns:

  • (Boolean) 


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# File 'lib/protocol/http/headers.rb', line 139

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

#initialize_dup(other) ⇒ Object 



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# File 'lib/protocol/http/headers.rb', line 57

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

#inspect ⇒ Object 



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# File 'lib/protocol/http/headers.rb', line 295

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

#keys ⇒ Object 



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# File 'lib/protocol/http/headers.rb', line 145

def keys
  self.to_h.keys
end

#merge(headers) ⇒ Object 



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# File 'lib/protocol/http/headers.rb', line 188

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

#merge!(headers) ⇒ Object 



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# File 'lib/protocol/http/headers.rb', line 180

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 174

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 287

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 111

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 104

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 88

def trailer?
  @tail != nil
end