## Amazon SimpleDB library
 ## Author: Michal Ludvig <michal@logix.cz>
 ##         http://www.logix.cz/michal
 ## License: GPL Version 2
 
 """
 Low-level class for working with Amazon SimpleDB
 """
 
 import time
 import urllib
 import base64
 import hmac
 import sha
 import httplib
 from logging import debug, info, warning, error
 
 from Utils import convertTupleListToDict
 from SortedDict import SortedDict
 from Exceptions import *
 
 class SimpleDB(object):

     # API Version
     # See http://docs.amazonwebservices.com/AmazonSimpleDB/2007-11-07/DeveloperGuide/
     Version = "2007-11-07"
     SignatureVersion = 1
 
     def __init__(self, config):
         self.config = config
 
     ## ------------------------------------------------
     ## Methods implementing SimpleDB API
     ## ------------------------------------------------
 
     def ListDomains(self, MaxNumberOfDomains = 100):
         '''
         Lists all domains associated with our Access Key. Returns
         domain names up to the limit set by MaxNumberOfDomains.
         '''
         parameters = SortedDict()
         parameters['MaxNumberOfDomains'] = MaxNumberOfDomains
         return self.send_request("ListDomains", DomainName = None, parameters = parameters)
 
     def CreateDomain(self, DomainName):
         return self.send_request("CreateDomain", DomainName = DomainName)
 
     def DeleteDomain(self, DomainName):
         return self.send_request("DeleteDomain", DomainName = DomainName)
 
     def PutAttributes(self, DomainName, ItemName, Attributes):
         parameters = SortedDict()
         parameters['ItemName'] = ItemName
         seq = 0
         for attrib in Attributes:
             if type(Attributes[attrib]) == type(list()):
                 for value in Attributes[attrib]:
                     parameters['Attribute.%d.Name' % seq] = attrib
                     parameters['Attribute.%d.Value' % seq] = unicode(value)
                     seq += 1
             else:
                 parameters['Attribute.%d.Name' % seq] = attrib
                 parameters['Attribute.%d.Value' % seq] = unicode(Attributes[attrib])
                 seq += 1
         ## TODO:
         ## - support for Attribute.N.Replace
         ## - support for multiple values for one attribute
         return self.send_request("PutAttributes", DomainName = DomainName, parameters = parameters)
 
     def GetAttributes(self, DomainName, ItemName, Attributes = []):
         parameters = SortedDict()
         parameters['ItemName'] = ItemName
         seq = 0
         for attrib in Attributes:
             parameters['AttributeName.%d' % seq] = attrib
             seq += 1
         return self.send_request("GetAttributes", DomainName = DomainName, parameters = parameters)
 
     def DeleteAttributes(self, DomainName, ItemName, Attributes = {}):
         """
         Remove specified Attributes from ItemName.
         Attributes parameter can be either:
         - not specified, in which case the whole Item is removed
         - list, e.g. ['Attr1', 'Attr2'] in which case these parameters are removed
         - dict, e.g. {'Attr' : 'One', 'Attr' : 'Two'} in which case the
           specified values are removed from multi-value attributes.
         """
         parameters = SortedDict()
         parameters['ItemName'] = ItemName
         seq = 0
         for attrib in Attributes:
             parameters['Attribute.%d.Name' % seq] = attrib
             if type(Attributes) == type(dict()):
                 parameters['Attribute.%d.Value' % seq] = unicode(Attributes[attrib])
             seq += 1
         return self.send_request("DeleteAttributes", DomainName = DomainName, parameters = parameters)
 
     def Query(self, DomainName, QueryExpression = None, MaxNumberOfItems = None, NextToken = None):
         parameters = SortedDict()
         if QueryExpression:
             parameters['QueryExpression'] = QueryExpression
         if MaxNumberOfItems:
             parameters['MaxNumberOfItems'] = MaxNumberOfItems
         if NextToken:
             parameters['NextToken'] = NextToken
         return self.send_request("Query", DomainName = DomainName, parameters = parameters)
         ## Handle NextToken? Or maybe not - let the upper level do it
 
     ## ------------------------------------------------
     ## Low-level methods for handling SimpleDB requests
     ## ------------------------------------------------
 
     def send_request(self, *args, **kwargs):
         request = self.create_request(*args, **kwargs)
         #debug("Request: %s" % repr(request))
         conn = self.get_connection()
         conn.request("GET", self.format_uri(request['uri_params']))
         http_response = conn.getresponse()
         response = {}
         response["status"] = http_response.status
         response["reason"] = http_response.reason
         response["headers"] = convertTupleListToDict(http_response.getheaders())
         response["data"] =  http_response.read()
         conn.close()
 
         if response["status"] < 200 or response["status"] > 299:
             debug("Response: " + str(response))
             raise S3Error(response)
 
         return response
 
     def create_request(self, Action, DomainName, parameters = None):
         if not parameters:
             parameters = SortedDict()
         parameters['AWSAccessKeyId'] = self.config.access_key
         parameters['Version'] = self.Version
         parameters['SignatureVersion'] = self.SignatureVersion
         parameters['Action'] = Action
         parameters['Timestamp'] = time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime())
         if DomainName:
             parameters['DomainName'] = DomainName
         parameters['Signature'] = self.sign_request(parameters)
         parameters.keys_return_lowercase = False
         uri_params = urllib.urlencode(parameters)
         request = {}
         request['uri_params'] = uri_params
         request['parameters'] = parameters
         return request
 
     def sign_request(self, parameters):
         h = ""
         parameters.keys_sort_lowercase = True
         parameters.keys_return_lowercase = False
         for key in parameters:
             h += "%s%s" % (key, parameters[key])
         #debug("SignRequest: %s" % h)
         return base64.encodestring(hmac.new(self.config.secret_key, h, sha).digest()).strip()
 
     def get_connection(self):
         if self.config.proxy_host != "":
             return httplib.HTTPConnection(self.config.proxy_host, self.config.proxy_port)
         else:
             if self.config.use_https:
                 return httplib.HTTPSConnection(self.config.simpledb_host)
             else:
                 return httplib.HTTPConnection(self.config.simpledb_host)
 
     def format_uri(self, uri_params):
         if self.config.proxy_host != "":
             uri = "http://%s/?%s" % (self.config.simpledb_host, uri_params)
         else:
             uri = "/?%s" % uri_params
         #debug('format_uri(): ' + uri)
         return uri
 
 # vim:et:ts=4:sts=4:ai