class FTW::HTTP::Headers

HTTP Headers

See RFC2616 section 4.2: <tools.ietf.org/html/rfc2616#section-4.2>

Section 14.44 says Field Names in the header are case-insensitive, so this library always forces field names to be lowercase. This includes get() calls.

headers.set("HELLO", "world")
headers.get("hello")   # ===> "world"

Public Class Methods

new(headers={}) click to toggle source

Make a new headers container.

@param [Hash, optional] a hash of headers to start with.

Calls superclass method
# File lib/ftw/http/headers.rb, line 24
def initialize(headers={})
  super()
  @headers = headers
end

Public Instance Methods

[](field)
Alias for: get
[]=(field, value)
Alias for: set
add(field, value) click to toggle source

Add a header field with a value.

If this field already exists, another value is added. If this field does not already exist, it is set.

# File lib/ftw/http/headers.rb, line 50
def add(field, value)
  field = field.downcase
  if @headers.include?(field)
    if @headers[field].is_a?(Array)
      @headers[field] << value
    else
      @headers[field] = [@headers[field], value]
    end
  else
    set(field, value)
  end
end
each() { |field_name, value| ... } click to toggle source

Iterate over headers. Given to the block are two arguments, the field name and the field value. For fields with multiple values, you will receive that same field name multiple times, like:

yield "Host", "www.example.com"
yield "X-Forwarded-For", "1.2.3.4"
yield "X-Forwarded-For", "1.2.3.5"
# File lib/ftw/http/headers.rb, line 117
def each(&block)
  @headers.each do |field_name, field_value|
    if field_value.is_a?(Array)
      field_value.map { |value| yield field_name, value }
    else
      yield field_name, field_value
    end
  end
end
get(field) click to toggle source

Get a field value.

@return [String] if there is only one value for this field @return [Array] if there are multiple values for this field @return [nil] if there are no values for this field

# File lib/ftw/http/headers.rb, line 104
def get(field)
  field = field.downcase
  return @headers[field]
end
Also aliased as: []
include?(field) click to toggle source

Does this header include this field name? @return [true, false]

# File lib/ftw/http/headers.rb, line 42
def include?(field)
  @headers.include?(field.downcase)
end
inspect() click to toggle source

Inspect this object

# File lib/ftw/http/headers.rb, line 151
def inspect
  return "#{self.class.name} <#{to_hash.inspect}>"
end
remove(field, value=nil) click to toggle source

Removes a header entry. If the header has multiple values (like X-Forwarded-For can), you can delete a specific entry by passing the value of the header field to remove.

# Remove all X-Forwarded-For entries
headers.remove("X-Forwarded-For") 
# Remove a specific X-Forwarded-For entry
headers.remove("X-Forwarded-For", "1.2.3.4")
  • If you remove a field that doesn't exist, no error will occur.

  • If you remove a field value that doesn't exist, no error will occur.

  • If you remove a field value that is the only value, it is the same as removing that field by name.

# File lib/ftw/http/headers.rb, line 76
def remove(field, value=nil)
  field = field.downcase
  if value.nil?
    # no value, given, remove the entire field.
    @headers.delete(field)
  else
    field_value = @headers[field]
    if field_value.is_a?(Array)
      # remove a specific value
      field_value.delete(value)
      # Down to a String again if there's only one value.
      if field_value.size == 1
        set(field, field_value.first)
      end
    else
      # Remove this field if the value matches
      if field_value == value
        remove(field)
      end
    end
  end
end
set(field, value) click to toggle source

Set a header field to a specific value. Any existing value(s) for this field are destroyed.

@param [String] the name of the field to set @param [String or Array] the value of the field to set

# File lib/ftw/http/headers.rb, line 34
def set(field, value)
  @headers[field.downcase] = value
end
Also aliased as: []=
to_hash() click to toggle source

@return [Hash] String keys and values of String (field value) or Array (of String field values)

# File lib/ftw/http/headers.rb, line 128
def to_hash
  return @headers
end
to_s() click to toggle source

Serialize this object to a string in HTTP format described by RFC2616

Example:

headers = FTW::HTTP::Headers.new
headers.add("Host", "example.com")
headers.add("X-Forwarded-For", "1.2.3.4")
headers.add("X-Forwarded-For", "192.168.0.1")
puts headers.to_s

# Result
Host: example.com
X-Forwarded-For: 1.2.3.4
X-Forwarded-For: 192.168.0.1
# File lib/ftw/http/headers.rb, line 146
def to_s
  return @headers.collect { |name, value| "#{name}: #{value}" }.join(CRLF) + CRLF
end