aws.py 文件源码

def query_biggest(self, hash_key, hash_value, num_items, index=None, forward=False):
        """Method to query for the largest N records

        Args:
            hash_key (str): Hash key name
            hash_value (str): Hash key value
            num_items (int): The number of items to return
            index (str): Name of index if not primary
            forward (bool): flag indicating sort direction

        Returns:
            dict
        """
        params = {"ScanIndexForward": forward,
                  "KeyConditionExpression": Key(hash_key).eq(hash_value),
                  "Select": "ALL_ATTRIBUTES",
                  "Limit": num_items}

        if index:
            params["IndexName"] = index
            params["Select"] = "ALL_PROJECTED_ATTRIBUTES"
        else:
            # If primary index, consistent read
            params["ConsistentRead"] = True

        response = self.table.query(**params)

        if response['ResponseMetadata']['HTTPStatusCode'] != 200:
            raise Exception("Error getting item: {}".format(response['ResponseMetadata']))

        if "Items" in response:
            if response["Items"]:
                return response["Items"]
            else:
                return []
        else:
            return []