Class: Elasticity::AwsRequest

Inherits:
Object
  • Object
show all
Defined in:
lib/elasticity/aws_request.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(access = nil, secret = nil, options = {}) ⇒ AwsRequest

Supported values for options:

:region - AWS region (e.g. us-west-1)
:secure - true or false, default true.



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# File 'lib/elasticity/aws_request.rb', line 18

def initialize(access=nil, secret=nil, options={})
  # There is a cryptic error if this isn't set
  if options.has_key?(:region) && options[:region] == nil
    raise MissingRegionError, 'A valid :region is required to connect to EMR'
  end

  @access_key = get_access_key(access)
  @secret_key = get_secret_key(secret)
  @host = "elasticmapreduce.#{{:region => 'us-east-1'}.merge(options)[:region]}.amazonaws.com"
  @protocol = {:secure => true}.merge(options)[:secure] ? 'https' : 'http'
end

Instance Attribute Details

#access_key ⇒ Object (readonly)

Returns the value of attribute access_key.



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# File 'lib/elasticity/aws_request.rb', line 10

def access_key
  @access_key
end

#host ⇒ Object (readonly)

Returns the value of attribute host.



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# File 'lib/elasticity/aws_request.rb', line 12

def host
  @host
end

#protocol ⇒ Object (readonly)

Returns the value of attribute protocol.



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# File 'lib/elasticity/aws_request.rb', line 13

def protocol
  @protocol
end

#secret_key ⇒ Object (readonly)

Returns the value of attribute secret_key.



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# File 'lib/elasticity/aws_request.rb', line 11

def secret_key
  @secret_key
end

Class Method Details

.aws_escape(param) ⇒ Object

(Used from RightScale’s right_aws gem) Escape a string according to Amazon’s rules. See: docs.amazonwebservices.com/AmazonSimpleDB/2007-11-07/DeveloperGuide/index.html?REST_RESTAuth.html



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# File 'lib/elasticity/aws_request.rb', line 85

def self.aws_escape(param)
  param.to_s.gsub(/([^a-zA-Z0-9._~-]+)/n) do
    '%' + $1.unpack('H2' * $1.size).join('%').upcase
  end
end

.camelize(word) ⇒ Object

(Used from Rails’ ActiveSupport)



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# File 'lib/elasticity/aws_request.rb', line 121

def self.camelize(word)
  word.to_s.gsub(/\/(.?)/) { "::" + $1.upcase }.gsub(/(^|_)(.)/) { $2.upcase }
end

.convert_ruby_to_aws(params) ⇒ Object

Since we use the same structure as AWS, we can generate AWS param names from the Ruby versions of those names (and the param nesting).



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# File 'lib/elasticity/aws_request.rb', line 93

def self.convert_ruby_to_aws(params)
  result = {}
  params.each do |key, value|
    case value
      when Array
        prefix = "#{camelize(key.to_s)}.member"
        value.each_with_index do |item, index|
          if item.is_a?(String)
            result["#{prefix}.#{index+1}"] = item
          else
            convert_ruby_to_aws(item).each do |nested_key, nested_value|
              result["#{prefix}.#{index+1}.#{nested_key}"] = nested_value
            end
          end
        end
      when Hash
        prefix = "#{camelize(key.to_s)}"
        convert_ruby_to_aws(value).each do |nested_key, nested_value|
          result["#{prefix}.#{nested_key}"] = nested_value
        end
      else
        result[camelize(key.to_s)] = value
    end
  end
  result
end

.parse_error_response(error_xml) ⇒ Object

AWS error responses all follow the same form. Extract the message from the error document.



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# File 'lib/elasticity/aws_request.rb', line 127

def self.parse_error_response(error_xml)
  xml_doc = Nokogiri::XML(error_xml)
  xml_doc.remove_namespaces!
  xml_doc.xpath("/ErrorResponse/Error/Message").text
end

Instance Method Details

#==(other) ⇒ Object 



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# File 'lib/elasticity/aws_request.rb', line 40

def ==(other)
  return false unless other.is_a? AwsRequest
  return false unless @access_key == other.access_key
  return false unless @secret_key == other.secret_key
  return false unless @host == other.host
  return false unless @protocol == other.protocol
  true
end

#submit(ruby_params) ⇒ Object 



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# File 'lib/elasticity/aws_request.rb', line 30

def submit(ruby_params)
  aws_params = AwsRequest.convert_ruby_to_aws(ruby_params)
  signed_params = sign_params(aws_params)
  begin
    RestClient.post("#@protocol://#@host", signed_params, :content_type => 'application/x-www-form-urlencoded; charset=utf-8')
  rescue RestClient::BadRequest => e
    raise ArgumentError, AwsRequest.parse_error_response(e.http_body)
  end
end