tdiary/rpaproxy-sinatra

# -*- coding: utf-8 -*-
#
require 'mongoid'
require 'yaml'
require 'net/http'

class Proxy
    include Mongoid::Document
    field :endpoint, type: String
    field :name, type: String
    field :locales, type: Array
    field :success, type: Integer, default: 0
    field :failure, type: Integer, default: 0

    belongs_to :user
    index({ locales: 1 })

    validates_presence_of :endpoint, :name, :locales
    validates_uniqueness_of :endpoint

    def self.random(locale)
        r = where(locales: locale).asc('_id').only(:endpoint, :_id).to_a
        r.concat(r.slice!(0, rand(r.length)))
    end

    def self.new_with_yaml(endpoint)
        uri = URI.parse(endpoint + 'rpaproxy.yaml')
        raise StandardError.new("エンドポイントのURLが不正です。: #{endpoint}") if uri.scheme != 'http'
        res = Net::HTTP.start(uri.host, uri.port) {|http|
            http.get(uri.path, {'User-Agent' => 'rpaproxy/0.01'})
        }
        yaml = YAML.load(res.body)
        ['name', 'locales'].each do |key|
            raise StandardError.new("Cannot read #{key} from #{uri}") unless yaml[key]
        end
        # TODO: localesの国別チェック
        new(endpoint: endpoint, name: yaml['name'], locales: yaml['locales'])
    end

    def fetch(locale, query_string)
        uri = URI.parse("#{endpoint}#{locale}/")
        begin
            res = Net::HTTP.start(uri.host, uri.port) {|http|
                http.get("#{uri.path}?#{query_string}", {'User-Agent' => 'rpaproxy/0.01'})
            }
            unless res.kind_of? Net::HTTPFound
                inc(failure: 1)
                return nil
            end
        rescue => e
            inc(failure: 1)
            return nil
        end
        inc(success: 1)
        res
    end

    def valid_endpoint?
        unless endpoint || locales
            return false
        end
        query = {
            Service: 'AWSECommerceService',
            AssociateTag: 'sample-22',
            SubscriptionId: '99999999999999999999',
            Version: '2007-10-29',
            Operation: 'ItemSearch',
            ResponseGroup: 'Small',
            SearchIndex: 'Books',
            Keywords: 'Amazon',
            ItemPage: '1',
            Timestamp: '2009-01-02T03:04:05Z'
        }.map{|k,v| "#{k}=#{v}"}.join("&")
        res = fetch(locales[0], query)
        return false unless res
        keys = URI.parse(res['location']).query.split('&').map{|k| k.split('=')[0]}
        # パラメタ内にあるAWSAccessKeyIdもしくはSubscriptionIdは、自身のアクセスキーに変更
        unless keys.include?('AWSAccessKeyId') || keys.include?('SubscriptionId')
            # TODO: errorsにエラーの理由を含める
            return false
        end
        # Timestampはパラメタにあっても無視し、現在時刻で付け直す
        # AssociateTagが指定されていない場合は自身のものを付加してよい
        ['Timestamp', 'Signature'].each do |excepted|
            return false unless keys.include?(excepted)
        end
        true
    end
end