Object
This class provides all the methods for using the EC2 or ELB service including the handling of header signing and other security concerns. This class uses the Net::HTTP library to interface with the AWS Query API interface. You should not instantiate this directly, instead you should setup an instance of 'AWS::EC2::Base' or 'AWS::ELB::Base'.
@option options [String] :access_key_id ("") The user's AWS Access Key ID @option options [String] :secret_access_key ("") The user's AWS Secret Access Key @option options [Boolean] :use_ssl (true) Connect using SSL? @option options [String] :server ("ec2.amazonaws.com") The server API endpoint host @option options [String] :proxy_server (nil) An HTTP proxy server FQDN @return [Object] the object.
# File lib/AWS.rb, line 123 def initialize( options = {} ) options = { :access_key_id => "", :secret_access_key => "", :use_ssl => true, :server => default_host, :path => "/", :proxy_server => nil }.merge(options) @server = options[:server] @proxy_server = options[:proxy_server] @use_ssl = options[:use_ssl] @path = options[:path] raise ArgumentError, "No :access_key_id provided" if options[:access_key_id].nil? || options[:access_key_id].empty? raise ArgumentError, "No :secret_access_key provided" if options[:secret_access_key].nil? || options[:secret_access_key].empty? raise ArgumentError, "No :use_ssl value provided" if options[:use_ssl].nil? raise ArgumentError, "Invalid :use_ssl value provided, only 'true' or 'false' allowed" unless options[:use_ssl] == true || options[:use_ssl] == false raise ArgumentError, "No :server provided" if options[:server].nil? || options[:server].empty? if options[:port] # user-specified port @port = options[:port] elsif @use_ssl # https @port = 443 else # http @port = 80 end @access_key_id = options[:access_key_id] @secret_access_key = options[:secret_access_key] # Use proxy server if defined # Based on patch by Mathias Dalheimer. 20070217 proxy = @proxy_server ? URI.parse(@proxy_server) : OpenStruct.new @http = Net::HTTP::Proxy( proxy.host, proxy.port, proxy.user, proxy.password).new(options[:server], @port) @http.use_ssl = @use_ssl # Don't verify the SSL certificates. Avoids SSL Cert warning in log on every GET. @http.verify_mode = OpenSSL::SSL::VERIFY_NONE end
If :user_data is passed in then URL escape and Base64 encode it as needed. Need for URL Escape + Base64 encoding is determined by :base64_encoded param.
# File lib/AWS.rb, line 176 def extract_user_data( options = {} ) return unless options[:user_data] if options[:user_data] if options[:base64_encoded] Base64.encode64(options[:user_data]).gsub(/\n/, "").strip() else options[:user_data] end end end
Raises the appropriate error if the specified Net::HTTPResponse object contains an AWS error; returns false otherwise.
# File lib/AWS.rb, line 332 def aws_error?(response) # return false if we got a HTTP 200 code, # otherwise there is some type of error (40x,50x) and # we should try to raise an appropriate exception # from one of our exception classes defined in # exceptions.rb return false if response.is_a?(Net::HTTPSuccess) raise AWS::Error, "Unexpected server error. response.body is: #{response.body}" if response.is_a?(Net::HTTPServerError) # parse the XML document so we can walk through it doc = REXML::Document.new(response.body) # Check that the Error element is in the place we would expect. # and if not raise a generic error exception unless doc.root.elements['Errors'].elements['Error'].name == 'Error' raise Error, "Unexpected error format. response.body is: #{response.body}" end # An valid error response looks like this: # <?xml version="1.0"?><Response><Errors><Error><Code>InvalidParameterCombination</Code><Message>Unknown parameter: foo</Message></Error></Errors><RequestID>291cef62-3e86-414b-900e-17246eccfae8</RequestID></Response> # AWS throws some exception codes that look like Error.SubError. Since we can't name classes this way # we need to strip out the '.' in the error 'Code' and we name the error exceptions with this # non '.' name as well. error_code = doc.root.elements['Errors'].elements['Error'].elements['Code'].text.gsub('.', '') error_message = doc.root.elements['Errors'].elements['Error'].elements['Message'].text # Raise one of our specific error classes if it exists. # otherwise, throw a generic EC2 Error with a few details. if AWS.const_defined?(error_code) raise AWS.const_get(error_code), error_message else raise AWS::Error, error_message end end
Set the Authorization header using AWS signed header authentication
# File lib/AWS.rb, line 308 def get_aws_auth_param(params, secret_access_key, server) canonical_string = AWS.canonical_string(params, server,"POST", @path) encoded_canonical = AWS.encode(secret_access_key, canonical_string) end
Make the connection to AWS EC2 passing in our request. This is generally called from within a 'Response' class object or one of its sub-classes so the response is interpreted in its proper context. See lib/EC2/responses.rb
# File lib/AWS.rb, line 272 def make_request(action, params, data='') @http.start do # remove any keys that have nil or empty values params.reject! { |key, value| value.nil? or value.empty?} params.merge!( {"Action" => action, "SignatureVersion" => "2", "SignatureMethod" => 'HmacSHA256', "AWSAccessKeyId" => @access_key_id, "Version" => api_version, "Timestamp"=>Time.now.getutc.iso8601} ) sig = get_aws_auth_param(params, @secret_access_key, @server) query = params.sort.collect do |param| CGI::escape(param[0]) + "=" + CGI::escape(param[1]) end.join("&") + "&Signature=" + sig req = Net::HTTP::Post.new(@path) req.content_type = 'application/x-www-form-urlencoded' req['User-Agent'] = "github-amazon-ec2-ruby-gem" response = @http.request(req, query) # Make a call to see if we need to throw an error based on the response given by EC2 # All error classes are defined in EC2/exceptions.rb aws_error?(response) return response end end
Same as pathlist except it deals with arrays of hashes. So if you pass in args ("People", [{:name=>'jon', :age=>'22'}, {:name=>'chris'}], {:name => 'Name', :age => 'Age'}) you should get {"People.1.Name"=>"jon", "People.1.Age"=>'22', 'People.2.Name'=>'chris'}
# File lib/AWS.rb, line 216 def pathhashlist(key, arr_of_hashes, mappings) raise ArgumentError, "expected a key that is a String" unless key.is_a? String raise ArgumentError, "expected a arr_of_hashes that is an Array" unless arr_of_hashes.is_a? Array arr_of_hashes.each{|h| raise ArgumentError, "expected each element of arr_of_hashes to be a Hash" unless h.is_a?(Hash)} raise ArgumentError, "expected a mappings that is an Hash" unless mappings.is_a? Hash params = {} arr_of_hashes.each_with_index do |hash, i| hash.each do |attribute, value| if value.is_a? Array params["#{key}.#{i+1}.Name"] = mappings[attribute] value.each_with_index do |item, j| params["#{key}.#{i+1}.Value.#{j+1}"] = item.to_s end else params["#{key}.#{i+1}.#{mappings[attribute]}"] = value.to_s end end end params end
Same as pathhashlist except it generates explicit <prefix>.Key= and <prefix>.Value or <prefix>.Value.1, <prefix>.Value.2 depending on whether the value is a scalar or an array.
So if you pass in args ("People", [{:name=>'jon'}, {:names=>['chris', 'bob']} with key_name = 'Key' and value_name = 'Value', you should get {"People.1.Key"=>"name", "People.1.Value"=>'jon', "People.2.Key"=>'names', 'People.2.Value.1'=>'chris', 'People.2.Value.2'=>'bob'}
# File lib/AWS.rb, line 244 def pathkvlist(key, arr_of_hashes, key_name, value_name, mappings) raise ArgumentError, "expected a key that is a String" unless key.is_a? String raise ArgumentError, "expected a arr_of_hashes that is an Array" unless arr_of_hashes.is_a? Array arr_of_hashes.each{|h| raise ArgumentError, "expected each element of arr_of_hashes to be a Hash" unless h.is_a?(Hash)} raise ArgumentError, "expected a key_nam that is a String" unless key_name.is_a? String raise ArgumentError, "expected a value_name that is a String" unless value_name.is_a? String raise ArgumentError, "expected a mappings that is an Hash" unless mappings.is_a? Hash params = {} arr_of_hashes.each_with_index do |hash, i| hash.each do |attribute, value| params["#{key}.#{i+1}.#{key_name}"] = mappings.fetch(attribute, attribute) if !value.nil? if value.is_a? Array value.each_with_index do |item, j| params["#{key}.#{i+1}.#{value_name}.#{j+1}"] = item.to_s end else params["#{key}.#{i+1}.#{value_name}"] = value.to_s end end end end params end
pathlist is a utility method which takes a key string and and array as input. It converts the array into a Hash with the hash key being 'Key.n' where 'n' increments by 1 for each iteration. So if you pass in args ("ImageId", ["123", "456"]) you should get {"ImageId.1"=>"123", "ImageId.2"=>"456"} returned.
# File lib/AWS.rb, line 195 def pathlist(key, arr) params = {} # ruby 1.9 will barf if we pass in a string instead of the array expected. # it will fail on each_with_index below since string is not enumerable. if arr.is_a? String new_arr = [] new_arr << arr arr = new_arr end arr.each_with_index do |value, i| params["#{key}.#{i+1}"] = value end params end
allow us to have a one line call in each method which will do all of the work in making the actual request to AWS.
# File lib/AWS.rb, line 315 def response_generator( options = {} ) options = { :action => "", :params => {} }.merge(options) raise ArgumentError, ":action must be provided to response_generator" if options[:action].nil? || options[:action].empty? http_response = make_request(options[:action], options[:params]) http_xml = http_response.body return Response.parse(:xml => http_xml) end
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