module AwsSdb
module Request
class Base
HOST = 'sdb.amazonaws.com'
attr_accessor :account, :secret, :params
def initialize(method, params, opts={})
@account = opts[:account] || ENV['AMAZON_ACCESS_KEY_ID']
@secret = opts[:secret] || ENV['AMAZON_SECRET_ACCESS_KEY']
raise <<-end_msg unless @account && @secret
Amazon AWS account or access key not defined
Please pass {:account => 'your account', :secret => 'your secret'}
as a last argument or define the following environment variables
ENV['AMAZON_ACCESS_KEY_ID']
ENV['AMAZON_SECRET_ACCESS_KEY']
end_msg
@method = method
@params = params
add_req_data_to_params
end
#Hostname for the request
def host
HOST
end
#Uri path
def path
'/'
end
#The full uri for the request, it takes the protocol as argument
def uri(protocol = 'http')
"#{protocol}://" + host + path + '?' + uri_query
end
#Only the query part of the uri
def uri_query
params_query + '&Signature=' + signature
end
alias :to_s :uri
private
def add_req_data_to_params
@params.update({'Version' => '2007-11-07',
'SignatureVersion' => '2',
'SignatureMethod' => 'HmacSHA256',
'AWSAccessKeyId' => @account,
'Timestamp' => Time.now.gmtime.iso8601})
end
def params_query
@params_query ||= @params.keys.sort.map do |key|
key + '=' + escape(@params[key].to_s)
end.join('&')
end
def data_to_sign
[@method, host, path, params_query].join("\n")
end
def signature
@signature ||= begin
digest = OpenSSL::Digest::Digest.new('sha256')
hmac = OpenSSL::HMAC.digest(digest, @secret, data_to_sign)
escape(Base64.encode64(hmac).strip)
end
end
def escape(string)
URI.escape(string, /[^-_.~a-zA-Z\d]/)
end
end
#Is the parent of all the request templates, defines some methods
class Template
class << self
#Generates method to allow shorter expressions in parameter
#definition takes an hash
#
# shortcuts({'LongUrlQueryParams' => :abbr})
#
#will cause :abbr params to be expanded in LongUrlQueryParams
def shortcuts(shortcuts_hash)
shortcuts_hash.each do |full_key, shortcut|
define_method("#{shortcut}=") do |value|
@params[full_key] = value
end
end
end
end
#takes the params for the request and an optional options hash
#params for the request are request specific, options accepted are only
#AWS credentials in form of
#
# {:account => 'your account', :secret => 'your secret'}
def initialize(params={}, opts={})
@params, @opts = params, opts
end
def token=(value)
@params['NextToken'] = value
end
def attributes=(attributes)
attributes.each_with_index do |attribute, index|
@params["AttributeName.#{index}"] = attribute.to_s
end
end
def request
expand!
@request ||= begin
Base.new('GET', @params.merge('Action' => self.class.to_s.split(':')[-1]), @opts)
end
end
[:to_s, :uri, :uri_query].each do |method|
define_method(method) do
request.send(method)
end
end
private
def expand!
@params.keys.each do |key|
send("#{key}=", @params.delete(key)) if respond_to?("#{key}=")
end
@params
end
end
#List the domains
#
# ListDomains.new({:max => 4}, {:account => 'account', :secret => 'secret'})
#
#Shortcut in params:
#
# :max - the maximum number of domain that can be returned
# :token - the token for follow up requests
class ListDomains < Template
shortcuts({'MaxNumberOfDomains' => :max})
end
#Creates a new domain
#
# CreateDomain.new({:name => 'my_domain'})
#
#Shortcut in params:
#
# :name - the name for the new domain
class CreateDomain < Template
shortcuts({'DomainName' => :name})
end
#Deletes a domain
#
# DeleteDomain.new({:name => 'my_domain'})
#
#Shortcut in params:
#
# :name - the name for domain
class DeleteDomain < Template
shortcuts({'DomainName' => :name})
end
#Provides informations for a domain
#
# DomainMetadata.new({:name => 'my_domain'})
#
#Shortcut in params:
#
# :name - the name for domain
class DomainMetadata < Template
shortcuts({'DomainName' => :name})
end
#Get the attributes for an item
#
# GetAttributes.new({:name => 'my_item', :attributes => [:first, :second]})
#
#Shortcut in params:
#
# :name - the item name
# :attributes - the list of the attributes to fetch, if not specified
# fetches all the attributes
class GetAttributes < Template
shortcuts({'ItemName' => :name, 'DomainName' => :domain})
end
#Add attributes to an item or create a new item whith the given attributes
#
# req = PutAttributes.new({:name => 'my_item'})
# req.attributes = {:color => :black, :shape => {:value => :square, :replace => true}}
#
#Note: in this request the value 'black' will be added to other color
#values if they already exist, while the shape value 'square' will replace
#pre existing values of shape
#the request, adding the :attributes to the params hash in the new method
#would have the same effect
#
#Note: in the sample above attributes are defined after initializing
#the request, adding the :attributes to the params hash in the new method
#would have the same effect
class PutAttributes < Template
attr_accessor :attributes
class << self
#multiple PutAttributes requests can be batched in one BatchPutAttributes
#just define the single PutAttributes and then pass them as args to
#the PutAttributes::batch method and you'll be returned the batched
#request.
#At the moment of writing the maximum number of requests you can batch
#are 25
def batch(*requests)
items_params = requests.map { |r| r.send(:expand!) }
first_request = requests.first.request
account = first_request.account
secret = first_request.secret
batch_params = {}
batch_params['DomainName'] ||= first_request.params['DomainName']
items_params.each_with_index do |params, index|
params.keys.each do |key|
batch_params["Item.#{index.to_s + '.' + key}"] = params[key] if key =~ /^ItemName|Attribute/
end
end
BatchPutAttributes.new(batch_params, {:account => account, :secret => secret})
end
end
shortcuts({'ItemName' => :name, 'DomainName' => :domain})
def expand_attributes!
index = 0
@attributes.keys.each do |attr_name|
replace = nil
values = case @attributes[attr_name]
when Hash
replace = @attributes[attr_name][:replace].to_s
@attributes[attr_name][:value].to_s
else
@attributes[attr_name].to_s
end
values = [values] unless values.is_a?(Array)
values.each do |value|
@params["Attribute.#{index}.Replace"] = replace if replace
@params["Attribute.#{index}.Name"] = attr_name.to_s
@params["Attribute.#{index}.Value"] = value
index += 1
end
end
end
private
def expand!
super
expand_attributes!
end
end
class BatchPutAttributes < Template
shortcuts({'DomainName' => :domain})
end
#delete some attributes from the given item, if no attributes
#are provided the whole item is deleted
#
# DeleteAttributes.new(:domain => 'test_domain', :name => 'item_1'
# :attributes => [:color, :shape])
class DeleteAttributes < Template
shortcuts({'ItemName' => :name, 'DomainName' => :domain})
end
#execute a select statement
# Select.new(:query => "SELECT * FROM test_domain")
class Select < Template
shortcuts({'SelectExpression' => :query})
end
#execute a query statement returns the array of the item names
#satisfying the statment
#
# Query.new(:domain => 'test_domain', :query => "['shape' = 'square']")
class Query < Template
shortcuts({'DomainName' => :domain,
'QueryExpression' => :query,
'MaxNumberOfItems' => :max})
end
#execute a query with attributes statement returns the items
#satisfying statement
#
# QueryWithAttributes.new(:domain => 'test_domain', :query => "['shape' = 'square']")
class QueryWithAttributes < Template
shortcuts({'DomainName' => :domain,
'QueryExpression' => :query,
'MaxNumberOfItems' => :max})
end
end
end