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 



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# File 'lib/protocol/http/headers.rb', line 65

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 101

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.



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# File 'lib/protocol/http/headers.rb', line 43

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 305

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 288

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.



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

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.



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# File 'lib/protocol/http/headers.rb', line 175

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

#clear ⇒ Object 



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

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 251

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 146

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

#empty? ⇒ Boolean 



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# File 'lib/protocol/http/headers.rb', line 142

def empty?
  @fields.empty?
end

#extract(keys) ⇒ Object 



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# File 'lib/protocol/http/headers.rb', line 158

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 96

def flatten
  self.dup.flatten!
end

#flatten! ⇒ Object

Flatten trailers into the headers.



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# File 'lib/protocol/http/headers.rb', line 87

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

#freeze ⇒ Object 



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# File 'lib/protocol/http/headers.rb', line 130

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

#include?(key) ⇒ Boolean 



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

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

#initialize_dup(other) ⇒ Object 



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

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 301

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

#keys ⇒ Object 



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# File 'lib/protocol/http/headers.rb', line 154

def keys
  self.to_h.keys
end

#merge(headers) ⇒ Object 



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# File 'lib/protocol/http/headers.rb', line 196

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

#merge!(headers) ⇒ Object 



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

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.



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# File 'lib/protocol/http/headers.rb', line 182

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 293

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, if there are any.



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

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

#trailers!(&block) ⇒ Object

Record the current headers, and prepare to receive trailers.



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# File 'lib/protocol/http/headers.rb', line 109

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

#trailers? ⇒ Boolean 



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

def trailers?
  @tail != nil
end