Class: EC2::Common::Headers

Inherits:
Object
  • Object
show all
Defined in:
lib/ec2/common/headers.rb

Constant Summary collapse

MANDATORY =

Order matters.

['content-md5', 'content-type', 'date']
X_AMZ_PREFIX = 
'x-amz'
X_AMZ_SECURITY_TOKEN = 
'x-amz-security-token'

Instance Method Summary collapse

Constructor Details

#initialize(verb) ⇒ Headers

Returns a new instance of Headers.

Raises:

  • (ArgumentError) 


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# File 'lib/ec2/common/headers.rb', line 18

def initialize(verb)
  raise ArgumentError.new('invalid verb') if verb.to_s.empty?
  @headers = {}
  @verb = verb
end

Instance Method Details

#add(name, value) ⇒ Object

Add a Header key-value pair.

Raises:

  • (ArgumentError) 


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# File 'lib/ec2/common/headers.rb', line 26

def add(name, value)
  raise ArgumentError.new("name '#{name.inspect}' must be a String") unless name.is_a? String
  raise ArgumentError.new("value '#{value.inspect}' (#{name}) must be a String") unless value.is_a? String
  @headers[name.downcase.strip] = value.strip
end

#get ⇒ Object

Return the headers as a map from header name to header value.



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# File 'lib/ec2/common/headers.rb', line 90

def get
  return @headers.clone
end

#sign(creds, aws_secret_access_key, url, bucket) ⇒ Object

Sign the headers using HMAC SHA1.



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# File 'lib/ec2/common/headers.rb', line 34

def sign(creds, aws_secret_access_key, url, bucket)
  aws_access_key_id = creds
  delegation_token = nil
  if (creds.is_a?(Hash))
      aws_access_key_id = creds['aws_access_key_id']
      aws_secret_access_key = creds['aws_secret_access_key']
      delegation_token = creds['aws_delegation_token']
  end

  @headers['date'] = Time.now.httpdate          # add HTTP Date header
  @headers['content-type'] ||= 'application/x-www-form-urlencoded'

  # Build the data to sign.
  data = @verb + "\n"

  # Deal with mandatory headers first:
  MANDATORY.each do |name|
    data += @headers.fetch(name, "") + "\n"
  end
 
  unless delegation_token.nil?
      @headers[X_AMZ_SECURITY_TOKEN] = delegation_token
  end
  # Add mandatory headers and those that start with the x-amz prefix.
  @headers.sort.each do |name, value|
    # Headers that start with x-amz must have both their name and value 
    # added.
    if name =~ /^#{X_AMZ_PREFIX}/
      data += name + ":" + value +"\n"
    end
  end
 
  uri = URI.parse(url)
  # Ignore everything in the URL after the question mark unless, by the
  # S3 protocol, it signifies an acl, torrent, logging or location parameter
  if uri.host.start_with? bucket
    data << "/#{bucket}"
  end
  data << if uri.path.empty?
    "/"
  else
    uri.path
  end
  ['acl', 'logging', 'torrent', 'location'].each do |item|
    regex = Regexp.new("[&?]#{item}($|&|=)")
    data << '?' + item if regex.match(url)
  end

  # Sign headers and then put signature back into headers.
  signature = Base64.encode64(Crypto::hmac_sha1(aws_secret_access_key, data))
  signature.chomp!
  @headers['Authorization'] = "AWS #{aws_access_key_id}:#{signature}"
end