python-boto 2.2.2-0ubuntu2 / usr / share / pyshared / boto / sdb / connection.py

# Copyright (c) 2006,2007 Mitch Garnaat http://garnaat.org/
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import xml.sax
import threading
import boto
from boto import handler
from boto.connection import AWSQueryConnection
from boto.sdb.domain import Domain, DomainMetaData
from boto.sdb.item import Item
from boto.sdb.regioninfo import SDBRegionInfo
from boto.exception import SDBResponseError

class ItemThread(threading.Thread):
    """
    A threaded :class:`Item <boto.sdb.item.Item>` retriever utility class. 
    Retrieved :class:`Item <boto.sdb.item.Item>` objects are stored in the
    ``items`` instance variable after :py:meth:`run() <run>` is called.
    
    .. tip:: The item retrieval will not start until
        the :func:`run() <boto.sdb.connection.ItemThread.run>` method is called.
    """
    def __init__(self, name, domain_name, item_names):
        """
        :param str name: A thread name. Used for identification.
        :param str domain_name: The name of a SimpleDB 
            :class:`Domain <boto.sdb.domain.Domain>`
        :type item_names: string or list of strings
        :param item_names: The name(s) of the items to retrieve from the specified
            :class:`Domain <boto.sdb.domain.Domain>`.
        :ivar list items: A list of items retrieved. Starts as empty list.
        """
        threading.Thread.__init__(self, name=name)
        #print 'starting %s with %d items' % (name, len(item_names))
        self.domain_name = domain_name
        self.conn = SDBConnection()
        self.item_names = item_names
        self.items = []

    def run(self):
        """
        Start the threaded retrieval of items. Populates the 
        ``items`` list with :class:`Item <boto.sdb.item.Item>` objects.
        """
        for item_name in self.item_names:
            item = self.conn.get_attributes(self.domain_name, item_name)
            self.items.append(item)

#boto.set_stream_logger('sdb')

class SDBConnection(AWSQueryConnection):
    """
    This class serves as a gateway to your SimpleDB region (defaults to
    us-east-1). Methods within allow access to SimpleDB 
    :class:`Domain <boto.sdb.domain.Domain>` objects and their associated
    :class:`Item <boto.sdb.item.Item>` objects.
    
    .. tip::
        While you may instantiate this class directly, it may be easier to
        go through :py:func:`boto.connect_sdb`.
    """
    DefaultRegionName = 'us-east-1'
    DefaultRegionEndpoint = 'sdb.amazonaws.com'
    APIVersion = '2009-04-15'
    ResponseError = SDBResponseError

    def __init__(self, aws_access_key_id=None, aws_secret_access_key=None,
                 is_secure=True, port=None, proxy=None, proxy_port=None,
                 proxy_user=None, proxy_pass=None, debug=0,
                 https_connection_factory=None, region=None, path='/',
                 converter=None, security_token=None):
        """
        For any keywords that aren't documented, refer to the parent class,
        :py:class:`boto.connection.AWSAuthConnection`. You can avoid having
        to worry about these keyword arguments by instantiating these objects
        via :py:func:`boto.connect_sdb`.
    
        :type region: :class:`boto.sdb.regioninfo.SDBRegionInfo`
        :keyword region: Explicitly specify a region. Defaults to ``us-east-1``
            if not specified. You may also specify the region in your ``boto.cfg``:

            .. code-block:: cfg

                [SDB]
                region = eu-west-1

        """
        if not region:
            region_name = boto.config.get('SDB', 'region', self.DefaultRegionName)
            for reg in boto.sdb.regions():
                if reg.name == region_name:
                    region = reg
                    break

        self.region = region
        AWSQueryConnection.__init__(self, aws_access_key_id,
                                    aws_secret_access_key,
                                    is_secure, port, proxy,
                                    proxy_port, proxy_user, proxy_pass,
                                    self.region.endpoint, debug,
                                    https_connection_factory, path,
                                    security_token=security_token)
        self.box_usage = 0.0
        self.converter = converter
        self.item_cls = Item

    def _required_auth_capability(self):
        return ['sdb']

    def set_item_cls(self, cls):
        """
        While the default item class is :py:class:`boto.sdb.item.Item`, this
        default may be overridden. Use this method to change a connection's
        item class.
        
        :param object cls: The new class to set as this connection's item
            class. See the default item class for inspiration as to what your
            replacement should/could look like.
        """
        self.item_cls = cls

    def _build_name_value_list(self, params, attributes, replace=False,
                              label='Attribute'):
        keys = attributes.keys()
        keys.sort()
        i = 1
        for key in keys:
            value = attributes[key]
            if isinstance(value, list):
                for v in value:
                    params['%s.%d.Name' % (label, i)] = key
                    if self.converter:
                        v = self.converter.encode(v)
                    params['%s.%d.Value' % (label, i)] = v
                    if replace:
                        params['%s.%d.Replace' % (label, i)] = 'true'
                    i += 1
            else:
                params['%s.%d.Name' % (label, i)] = key
                if self.converter:
                    value = self.converter.encode(value)
                params['%s.%d.Value' % (label, i)] = value
                if replace:
                    params['%s.%d.Replace' % (label, i)] = 'true'
            i += 1

    def _build_expected_value(self, params, expected_value):
        params['Expected.1.Name'] = expected_value[0]
        if expected_value[1] is True:
            params['Expected.1.Exists'] = 'true'
        elif expected_value[1] is False:
            params['Expected.1.Exists'] = 'false'
        else:
            params['Expected.1.Value'] = expected_value[1]

    def _build_batch_list(self, params, items, replace=False):
        item_names = items.keys()
        i = 0
        for item_name in item_names:
            params['Item.%d.ItemName' % i] = item_name
            j = 0
            item = items[item_name]
            if item is not None:
                attr_names = item.keys()
                for attr_name in attr_names:
                    value = item[attr_name]
                    if isinstance(value, list):
                        for v in value:
                            if self.converter:
                                v = self.converter.encode(v)
                            params['Item.%d.Attribute.%d.Name' % (i, j)] = attr_name
                            params['Item.%d.Attribute.%d.Value' % (i, j)] = v
                            if replace:
                                params['Item.%d.Attribute.%d.Replace' % (i, j)] = 'true'
                            j += 1
                    else:
                        params['Item.%d.Attribute.%d.Name' % (i, j)] = attr_name
                        if self.converter:
                            value = self.converter.encode(value)
                        params['Item.%d.Attribute.%d.Value' % (i, j)] = value
                        if replace:
                            params['Item.%d.Attribute.%d.Replace' % (i, j)] = 'true'
                        j += 1
            i += 1

    def _build_name_list(self, params, attribute_names):
        i = 1
        attribute_names.sort()
        for name in attribute_names:
            params['Attribute.%d.Name' % i] = name
            i += 1

    def get_usage(self):
        """
        Returns the BoxUsage (in USD) accumulated on this specific SDBConnection 
        instance.

        .. tip:: This can be out of date, and should only be treated as a
            rough estimate. Also note that this estimate only applies to the
            requests made on this specific connection instance. It is by
            no means an account-wide estimate.

        :rtype: float
        :return: The accumulated BoxUsage of all requests made on the connection.
        """
        return self.box_usage

    def print_usage(self):
        """
        Print the BoxUsage and approximate costs of all requests made on
        this specific SDBConnection instance.
        
        .. tip:: This can be out of date, and should only be treated as a
            rough estimate. Also note that this estimate only applies to the
            requests made on this specific connection instance. It is by
            no means an account-wide estimate.
        """
        print 'Total Usage: %f compute seconds' % self.box_usage
        cost = self.box_usage * 0.14
        print 'Approximate Cost: $%f' % cost

    def get_domain(self, domain_name, validate=True):
        """
        Retrieves a :py:class:`boto.sdb.domain.Domain` object whose name
        matches ``domain_name``.
        
        :param str domain_name: The name of the domain to retrieve
        :keyword bool validate: When ``True``, check to see if the domain
            actually exists. If ``False``, blindly return a
            :py:class:`Domain <boto.sdb.domain.Domain>` object with the 
            specified name set.

        :raises: 
            :py:class:`boto.exception.SDBResponseError` if ``validate`` is
            ``True`` and no match could be found.

        :rtype: :py:class:`boto.sdb.domain.Domain`
        :return: The requested domain
        """
        domain = Domain(self, domain_name)
        if validate:
            self.select(domain, """select * from `%s` limit 1""" % domain_name)
        return domain

    def lookup(self, domain_name, validate=True):
        """
        Lookup an existing SimpleDB domain. This differs from 
        :py:meth:`get_domain` in that ``None`` is returned if ``validate`` is
        ``True`` and no match was found (instead of raising an exception).

        :param str domain_name: The name of the domain to retrieve
        
        :param bool validate: If ``True``, a ``None`` value will be returned
            if the specified domain can't be found. If ``False``, a
            :py:class:`Domain <boto.sdb.domain.Domain>` object will be dumbly
            returned, regardless of whether it actually exists.

        :rtype: :class:`boto.sdb.domain.Domain` object or ``None``
        :return: The Domain object or ``None`` if the domain does not exist.
        """
        try:
            domain = self.get_domain(domain_name, validate)
        except:
            domain = None
        return domain

    def get_all_domains(self, max_domains=None, next_token=None):
        """
        Returns a :py:class:`boto.resultset.ResultSet` containing
        all :py:class:`boto.sdb.domain.Domain` objects associated with
        this connection's Access Key ID.
        
        :keyword int max_domains: Limit the returned 
            :py:class:`ResultSet <boto.resultset.ResultSet>` to the specified
            number of members.
        :keyword str next_token: A token string that was returned in an
            earlier call to this method as the ``next_token`` attribute
            on the returned :py:class:`ResultSet <boto.resultset.ResultSet>`
            object. This attribute is set if there are more than Domains than
            the value specified in the ``max_domains`` keyword. Pass the
            ``next_token`` value from you earlier query in this keyword to
            get the next 'page' of domains.
        """
        params = {}
        if max_domains:
            params['MaxNumberOfDomains'] = max_domains
        if next_token:
            params['NextToken'] = next_token
        return self.get_list('ListDomains', params, [('DomainName', Domain)])

    def create_domain(self, domain_name):
        """
        Create a SimpleDB domain.

        :type domain_name: string
        :param domain_name: The name of the new domain

        :rtype: :class:`boto.sdb.domain.Domain` object
        :return: The newly created domain
        """
        params = {'DomainName':domain_name}
        d = self.get_object('CreateDomain', params, Domain)
        d.name = domain_name
        return d

    def get_domain_and_name(self, domain_or_name):
        """
        Given a ``str`` or :class:`boto.sdb.domain.Domain`, return a
        ``tuple`` with the following members (in order):
        
            * In instance of :class:`boto.sdb.domain.Domain` for the requested
              domain
            * The domain's name as a ``str``
            
        :type domain_or_name: ``str`` or :class:`boto.sdb.domain.Domain`
        :param domain_or_name: The domain or domain name to get the domain
            and name for.
            
        :raises: :class:`boto.exception.SDBResponseError` when an invalid
            domain name is specified.
            
        :rtype: tuple
        :return: A ``tuple`` with contents outlined as per above.
        """
        if (isinstance(domain_or_name, Domain)):
            return (domain_or_name, domain_or_name.name)
        else:
            return (self.get_domain(domain_or_name), domain_or_name)

    def delete_domain(self, domain_or_name):
        """
        Delete a SimpleDB domain.

        .. caution:: This will delete the domain and all items within the domain.

        :type domain_or_name: string or :class:`boto.sdb.domain.Domain` object.
        :param domain_or_name: Either the name of a domain or a Domain object

        :rtype: bool
        :return: True if successful
        
        """
        domain, domain_name = self.get_domain_and_name(domain_or_name)
        params = {'DomainName':domain_name}
        return self.get_status('DeleteDomain', params)

    def domain_metadata(self, domain_or_name):
        """
        Get the Metadata for a SimpleDB domain.

        :type domain_or_name: string or :class:`boto.sdb.domain.Domain` object.
        :param domain_or_name: Either the name of a domain or a Domain object

        :rtype: :class:`boto.sdb.domain.DomainMetaData` object
        :return: The newly created domain metadata object
        """
        domain, domain_name = self.get_domain_and_name(domain_or_name)
        params = {'DomainName':domain_name}
        d = self.get_object('DomainMetadata', params, DomainMetaData)
        d.domain = domain
        return d

    def put_attributes(self, domain_or_name, item_name, attributes,
                       replace=True, expected_value=None):
        """
        Store attributes for a given item in a domain.
        
        :type domain_or_name: string or :class:`boto.sdb.domain.Domain` object.
        :param domain_or_name: Either the name of a domain or a Domain object
        
        :type item_name: string
        :param item_name: The name of the item whose attributes are being
                          stored.
        
        :type attribute_names: dict or dict-like object
        :param attribute_names: The name/value pairs to store as attributes
        
        :type expected_value: list
        :param expected_value: If supplied, this is a list or tuple consisting
            of a single attribute name and expected value. The list can be 
            of the form:
            
                * ['name', 'value']
             
            In which case the call will first verify that the attribute "name" 
            of this item has a value of "value".  If it does, the delete
            will proceed, otherwise a ConditionalCheckFailed error will be 
            returned. The list can also be of the form:
            
                * ['name', True|False]
            
            which will simply check for the existence (True) or 
            non-existence (False) of the attribute.
        
        :type replace: bool
        :param replace: Whether the attribute values passed in will replace
                        existing values or will be added as addition values.
                        Defaults to True.
        
        :rtype: bool
        :return: True if successful
        """
        domain, domain_name = self.get_domain_and_name(domain_or_name)
        params = {'DomainName' : domain_name,
                  'ItemName' : item_name}
        self._build_name_value_list(params, attributes, replace)
        if expected_value:
            self._build_expected_value(params, expected_value)
        return self.get_status('PutAttributes', params)

    def batch_put_attributes(self, domain_or_name, items, replace=True):
        """
        Store attributes for multiple items in a domain.
        
        :type domain_or_name: string or :class:`boto.sdb.domain.Domain` object.
        :param domain_or_name: Either the name of a domain or a Domain object

        :type items: dict or dict-like object
        :param items: A dictionary-like object.  The keys of the dictionary are
                      the item names and the values are themselves dictionaries
                      of attribute names/values, exactly the same as the
                      attribute_names parameter of the scalar put_attributes
                      call.
        
        :type replace: bool
        :param replace: Whether the attribute values passed in will replace
                        existing values or will be added as addition values.
                        Defaults to True.
        
        :rtype: bool
        :return: True if successful
        """
        domain, domain_name = self.get_domain_and_name(domain_or_name)
        params = {'DomainName' : domain_name}
        self._build_batch_list(params, items, replace)
        return self.get_status('BatchPutAttributes', params, verb='POST')

    def get_attributes(self, domain_or_name, item_name, attribute_names=None,
                       consistent_read=False, item=None):
        """
        Retrieve attributes for a given item in a domain.

        :type domain_or_name: string or :class:`boto.sdb.domain.Domain` object.
        :param domain_or_name: Either the name of a domain or a Domain object

        :type item_name: string
        :param item_name: The name of the item whose attributes are 
            being retrieved.

        :type attribute_names: string or list of strings
        :param attribute_names: An attribute name or list of attribute names.
            This parameter is optional.  If not supplied, all attributes will 
            be retrieved for the item.

        :type consistent_read: bool
        :param consistent_read: When set to true, ensures that the most recent
            data is returned.
                                
        :type item: :class:`boto.sdb.item.Item`
        :keyword item: Instead of instantiating a new Item object, you may
            specify one to update.

        :rtype: :class:`boto.sdb.item.Item`
        :return: An Item with the requested attribute name/values set on it
        """
        domain, domain_name = self.get_domain_and_name(domain_or_name)
        params = {'DomainName' : domain_name,
                  'ItemName' : item_name}
        if consistent_read:
            params['ConsistentRead'] = 'true'
        if attribute_names:
            if not isinstance(attribute_names, list):
                attribute_names = [attribute_names]
            self.build_list_params(params, attribute_names, 'AttributeName')
        response = self.make_request('GetAttributes', params)
        body = response.read()
        if response.status == 200:
            if item == None:
                item = self.item_cls(domain, item_name)
            h = handler.XmlHandler(item, self)
            xml.sax.parseString(body, h)
            return item
        else:
            raise SDBResponseError(response.status, response.reason, body)

    def delete_attributes(self, domain_or_name, item_name, attr_names=None,
                          expected_value=None):
        """
        Delete attributes from a given item in a domain.

        :type domain_or_name: string or :class:`boto.sdb.domain.Domain` object.
        :param domain_or_name: Either the name of a domain or a Domain object

        :type item_name: string
        :param item_name: The name of the item whose attributes are being
                          deleted.

        :type attributes: dict, list or :class:`boto.sdb.item.Item`
        :param attributes: Either a list containing attribute names which
                           will cause all values associated with that attribute
                           name to be deleted or a dict or Item containing the
                           attribute names and keys and list of values to
                           delete as the value.  If no value is supplied,
                           all attribute name/values for the item will be
                           deleted.
                           
        :type expected_value: list
        :param expected_value: If supplied, this is a list or tuple consisting
            of a single attribute name and expected value. The list can be 
            of the form:

                * ['name', 'value']

            In which case the call will first verify that the attribute "name" 
            of this item has a value of "value".  If it does, the delete
            will proceed, otherwise a ConditionalCheckFailed error will be 
            returned. The list can also be of the form:

                * ['name', True|False]

            which will simply check for the existence (True) or 
            non-existence (False) of the attribute.

        :rtype: bool
        :return: True if successful
        """
        domain, domain_name = self.get_domain_and_name(domain_or_name)
        params = {'DomainName':domain_name,
                  'ItemName' : item_name}
        if attr_names:
            if isinstance(attr_names, list):
                self._build_name_list(params, attr_names)
            elif isinstance(attr_names, dict) or isinstance(attr_names, self.item_cls):
                self._build_name_value_list(params, attr_names)
        if expected_value:
            self._build_expected_value(params, expected_value)
        return self.get_status('DeleteAttributes', params)

    def batch_delete_attributes(self, domain_or_name, items):
        """
        Delete multiple items in a domain.
        
        :type domain_or_name: string or :class:`boto.sdb.domain.Domain` object.
        :param domain_or_name: Either the name of a domain or a Domain object

        :type items: dict or dict-like object
        :param items: A dictionary-like object.  The keys of the dictionary are
            the item names and the values are either:
            
                * dictionaries of attribute names/values, exactly the
                  same as the attribute_names parameter of the scalar
                  put_attributes call.  The attribute name/value pairs
                  will only be deleted if they match the name/value
                  pairs passed in.
                * None which means that all attributes associated
                  with the item should be deleted.  

        :return: True if successful
        """
        domain, domain_name = self.get_domain_and_name(domain_or_name)
        params = {'DomainName' : domain_name}
        self._build_batch_list(params, items, False)
        return self.get_status('BatchDeleteAttributes', params, verb='POST')

    def select(self, domain_or_name, query='', next_token=None,
               consistent_read=False):
        """
        Returns a set of Attributes for item names within domain_name that
        match the query.  The query must be expressed in using the SELECT
        style syntax rather than the original SimpleDB query language.
        Even though the select request does not require a domain object,
        a domain object must be passed into this method so the Item objects
        returned can point to the appropriate domain.
        
        :type domain_or_name: string or :class:`boto.sdb.domain.Domain` object
        :param domain_or_name: Either the name of a domain or a Domain object

        :type query: string
        :param query: The SimpleDB query to be performed.

        :type consistent_read: bool
        :param consistent_read: When set to true, ensures that the most recent
                                data is returned.

        :rtype: ResultSet
        :return: An iterator containing the results.
        """
        domain, domain_name = self.get_domain_and_name(domain_or_name)
        params = {'SelectExpression' : query}
        if consistent_read:
            params['ConsistentRead'] = 'true'
        if next_token:
            params['NextToken'] = next_token
        try:
            return self.get_list('Select', params, [('Item', self.item_cls)],
                             parent=domain)
        except SDBResponseError, e:
            e.body = "Query: %s\n%s" % (query, e.body)
            raise e