Class: Amazon::SDB::Base

Inherits:
Object
  • Object
show all
Defined in:
lib/amazon_sdb/base.rb

Overview

The Amazon::SDS::Base class is the top-level interface class for your SDS interactions. It allows you to set global configuration settings, to manage Domain objects. If you are working within a particular domain you can also just use the domain initializer directly for that domain.

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(aws_access_key, aws_secret_key) ⇒ Base

The base is initialized with 2 parameters from your Amazon Web Services account:

  • aws_access_key - Your AWS Access Key

  • aws_secret_key - Your AWS Secret Key



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# File 'lib/amazon_sdb/base.rb', line 15

def initialize(aws_access_key, aws_secret_key)
  @access_key = aws_access_key
  @secret_key = aws_secret_key
  @usage = Usage.new
end

Class Method Details

.float_precision ⇒ Object

The number of digits after the decimal points to use by default



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# File 'lib/amazon_sdb/base.rb', line 38

def self.float_precision
  return @@float_precision
end

.float_precision=(num) ⇒ Object

Set the #float_precision



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# File 'lib/amazon_sdb/base.rb', line 44

def self.float_precision=(num)
  return @@float_precision
end

.number_padding ⇒ Object

Since all SDS supports only lexical comparisons, it’s necessary to pad numbers with extra digits when saving them to SDS. Under lexical matching, 23 > 123. But if we pad it sufficiently 000000023 < 000000123. By default, this is set to the ungodly large value of 32 digits, but you can adjust it lower if this is too much. On reading from SDS, such numbers are auto-coerced back, so it’s probably not necessary to change.



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# File 'lib/amazon_sdb/base.rb', line 26

def self.number_padding
  return @@number_padding
end

.number_padding=(num) ⇒ Object

Change the number padding



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# File 'lib/amazon_sdb/base.rb', line 32

def self.number_padding=(num)
  @@number_padding = num
end

Instance Method Details

#box_usage ⇒ Object

Returns the Box Usage accumulated since the beginning of the session. Box Usage represents computation time and is one of the parameters in your monthly SimpleDB bill. As an alternative, when passed a block (no parameters yielded), it returns the box usage only for the operations within the block.



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# File 'lib/amazon_sdb/base.rb', line 52

def box_usage
  unless block_given?
    @usage.box_usage
  else
    # return the usage of the actions in the block
    usage1 = @usage.box_usage
    yield
    usage2 = @usage.box_usage
    return usage2 - usage1
  end
end

#create_domain(name) ⇒ Object

Creates a domain. This operation is idempotent, but it is slow and if you are sure the domain already exists, you might want to use the #domain method instead. Each SimpleDB account is allowed up to 100 domains; a LimitError will be raised if you attempt to create more.



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# File 'lib/amazon_sdb/base.rb', line 107

def create_domain(name)
  sdb_query({:Action => 'CreateDomain', 'DomainName' => name}) do |h|
    domain(name)
  end
end

#delete_domain!(name) ⇒ Object

Deletes a domain. Running this command multiple times or on a domain that does not exist will NOT return an error.



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# File 'lib/amazon_sdb/base.rb', line 115

def delete_domain!(name)
  sdb_query({:Action => 'DeleteDomain', 'DomainName' => name})
end

#domain(name) ⇒ Object

Returns a domain object for SimpleDB. Assumes the domain already exists, so a ParameterError (NoSuchDomain) might occur if it’s not there. This method is useful for getting a domain object without having to incur the operational costs of querying all domains.



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# File 'lib/amazon_sdb/base.rb', line 99

def domain(name)
  Domain.new(self, name)
end

#domains ⇒ Object

Retrieves a list of domains in your SDS database. Each entry is a Domain object.



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# File 'lib/amazon_sdb/base.rb', line 72

def domains
  domains = []
  nextToken = nil
  base_options = {:Action => 'ListDomains'}
  continue = true
  
  while continue
    options = base_options.dup
    options[:NextToken] = nextToken unless nextToken.nil?
    
    sdb_query(options) do |h|
      h.search('//DomainName').each {|e| domains << Domain.new(self, e.innerText)}
      mt = h.at('//NextToken')
      if mt
        nextToken = mt.innerText
      else
        continue = false
      end
    end
  end
  
  domains
end

#reset_usage! ⇒ Object

Resets the box usage accumulated within the current session. Not sure why you’d need to do this, but it’s provided.



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# File 'lib/amazon_sdb/base.rb', line 66

def reset_usage!
  @usage.reset!
end