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+# Copyright 2011 Canonical Ltd.
+#
+# This file is part of u1db.
+#
+# u1db is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3
+# as published by the Free Software Foundation.
+#
+# u1db is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with u1db. If not, see <http://www.gnu.org/licenses/>.
+
+"""U1DB"""
+
+try:
+ import simplejson as json
+except ImportError:
+ import json # noqa
+
+from u1db.errors import InvalidJSON, InvalidContent
+
+__version_info__ = (0, 1, 4)
+__version__ = '.'.join(map(str, __version_info__))
+
+
+def open(path, create, document_factory=None):
+ """Open a database at the given location.
+
+ Will raise u1db.errors.DatabaseDoesNotExist if create=False and the
+ database does not already exist.
+
+ :param path: The filesystem path for the database to open.
+ :param create: True/False, should the database be created if it doesn't
+ already exist?
+ :param document_factory: A function that will be called with the same
+ parameters as Document.__init__.
+ :return: An instance of Database.
+ """
+ from u1db.backends import sqlite_backend
+ return sqlite_backend.SQLiteDatabase.open_database(
+ path, create=create, document_factory=document_factory)
+
+
+# constraints on database names (relevant for remote access, as regex)
+DBNAME_CONSTRAINTS = r"[a-zA-Z0-9][a-zA-Z0-9.-]*"
+
+# constraints on doc ids (as regex)
+# (no slashes, and no characters outside the ascii range)
+DOC_ID_CONSTRAINTS = r"[a-zA-Z0-9.%_-]+"
+
+
+class Database(object):
+ """A JSON Document data store.
+
+ This data store can be synchronized with other u1db.Database instances.
+ """
+
+ def set_document_factory(self, factory):
+ """Set the document factory that will be used to create objects to be
+ returned as documents by the database.
+
+ :param factory: A function that returns an object which at minimum must
+ satisfy the same interface as does the class DocumentBase.
+ Subclassing that class is the easiest way to create such
+ a function.
+ """
+ raise NotImplementedError(self.set_document_factory)
+
+ def set_document_size_limit(self, limit):
+ """Set the maximum allowed document size for this database.
+
+ :param limit: Maximum allowed document size in bytes.
+ """
+ raise NotImplementedError(self.set_document_size_limit)
+
+ def whats_changed(self, old_generation=0):
+ """Return a list of documents that have changed since old_generation.
+ This allows APPS to only store a db generation before going
+ 'offline', and then when coming back online they can use this
+ data to update whatever extra data they are storing.
+
+ :param old_generation: The generation of the database in the old
+ state.
+ :return: (generation, trans_id, [(doc_id, generation, trans_id),...])
+ The current generation of the database, its associated transaction
+ id, and a list of of changed documents since old_generation,
+ represented by tuples with for each document its doc_id and the
+ generation and transaction id corresponding to the last intervening
+ change and sorted by generation (old changes first)
+ """
+ raise NotImplementedError(self.whats_changed)
+
+ def get_doc(self, doc_id, include_deleted=False):
+ """Get the JSON string for the given document.
+
+ :param doc_id: The unique document identifier
+ :param include_deleted: If set to True, deleted documents will be
+ returned with empty content. Otherwise asking for a deleted
+ document will return None.
+ :return: a Document object.
+ """
+ raise NotImplementedError(self.get_doc)
+
+ def get_docs(self, doc_ids, check_for_conflicts=True,
+ include_deleted=False):
+ """Get the JSON content for many documents.
+
+ :param doc_ids: A list of document identifiers.
+ :param check_for_conflicts: If set to False, then the conflict check
+ will be skipped, and 'None' will be returned instead of True/False.
+ :param include_deleted: If set to True, deleted documents will be
+ returned with empty content. Otherwise deleted documents will not
+ be included in the results.
+ :return: iterable giving the Document object for each document id
+ in matching doc_ids order.
+ """
+ raise NotImplementedError(self.get_docs)
+
+ def get_all_docs(self, include_deleted=False):
+ """Get the JSON content for all documents in the database.
+
+ :param include_deleted: If set to True, deleted documents will be
+ returned with empty content. Otherwise deleted documents will not
+ be included in the results.
+ :return: (generation, [Document])
+ The current generation of the database, followed by a list of all
+ the documents in the database.
+ """
+ raise NotImplementedError(self.get_all_docs)
+
+ def create_doc(self, content, doc_id=None):
+ """Create a new document.
+
+ You can optionally specify the document identifier, but the document
+ must not already exist. See 'put_doc' if you want to override an
+ existing document.
+ If the database specifies a maximum document size and the document
+ exceeds it, create will fail and raise a DocumentTooBig exception.
+
+ :param content: A Python dictionary.
+ :param doc_id: An optional identifier specifying the document id.
+ :return: Document
+ """
+ raise NotImplementedError(self.create_doc)
+
+ def create_doc_from_json(self, json, doc_id=None):
+ """Create a new document.
+
+ You can optionally specify the document identifier, but the document
+ must not already exist. See 'put_doc' if you want to override an
+ existing document.
+ If the database specifies a maximum document size and the document
+ exceeds it, create will fail and raise a DocumentTooBig exception.
+
+ :param json: The JSON document string
+ :param doc_id: An optional identifier specifying the document id.
+ :return: Document
+ """
+ raise NotImplementedError(self.create_doc_from_json)
+
+ def put_doc(self, doc):
+ """Update a document.
+ If the document currently has conflicts, put will fail.
+ If the database specifies a maximum document size and the document
+ exceeds it, put will fail and raise a DocumentTooBig exception.
+
+ :param doc: A Document with new content.
+ :return: new_doc_rev - The new revision identifier for the document.
+ The Document object will also be updated.
+ """
+ raise NotImplementedError(self.put_doc)
+
+ def delete_doc(self, doc):
+ """Mark a document as deleted.
+ Will abort if the current revision doesn't match doc.rev.
+ This will also set doc.content to None.
+ """
+ raise NotImplementedError(self.delete_doc)
+
+ def create_index(self, index_name, *index_expressions):
+ """Create an named index, which can then be queried for future lookups.
+ Creating an index which already exists is not an error, and is cheap.
+ Creating an index which does not match the index_expressions of the
+ existing index is an error.
+ Creating an index will block until the expressions have been evaluated
+ and the index generated.
+
+ :param index_name: A unique name which can be used as a key prefix
+ :param index_expressions: index expressions defining the index
+ information.
+
+ Examples:
+
+ "fieldname", or "fieldname.subfieldname" to index alphabetically
+ sorted on the contents of a field.
+
+ "number(fieldname, width)", "lower(fieldname)"
+ """
+ raise NotImplementedError(self.create_index)
+
+ def delete_index(self, index_name):
+ """Remove a named index.
+
+ :param index_name: The name of the index we are removing
+ """
+ raise NotImplementedError(self.delete_index)
+
+ def list_indexes(self):
+ """List the definitions of all known indexes.
+
+ :return: A list of [('index-name', ['field', 'field2'])] definitions.
+ """
+ raise NotImplementedError(self.list_indexes)
+
+ def get_from_index(self, index_name, *key_values):
+ """Return documents that match the keys supplied.
+
+ You must supply exactly the same number of values as have been defined
+ in the index. It is possible to do a prefix match by using '*' to
+ indicate a wildcard match. You can only supply '*' to trailing entries,
+ (eg 'val', '*', '*' is allowed, but '*', 'val', 'val' is not.)
+ It is also possible to append a '*' to the last supplied value (eg
+ 'val*', '*', '*' or 'val', 'val*', '*', but not 'val*', 'val', '*')
+
+ :param index_name: The index to query
+ :param key_values: values to match. eg, if you have
+ an index with 3 fields then you would have:
+ get_from_index(index_name, val1, val2, val3)
+ :return: List of [Document]
+ """
+ raise NotImplementedError(self.get_from_index)
+
+ def get_range_from_index(self, index_name, start_value, end_value):
+ """Return documents that fall within the specified range.
+
+ Both ends of the range are inclusive. For both start_value and
+ end_value, one must supply exactly the same number of values as have
+ been defined in the index, or pass None. In case of a single column
+ index, a string is accepted as an alternative for a tuple with a single
+ value. It is possible to do a prefix match by using '*' to indicate
+ a wildcard match. You can only supply '*' to trailing entries, (eg
+ 'val', '*', '*' is allowed, but '*', 'val', 'val' is not.) It is also
+ possible to append a '*' to the last supplied value (eg 'val*', '*',
+ '*' or 'val', 'val*', '*', but not 'val*', 'val', '*')
+
+ :param index_name: The index to query
+ :param start_values: tuples of values that define the lower bound of
+ the range. eg, if you have an index with 3 fields then you would
+ have: (val1, val2, val3)
+ :param end_values: tuples of values that define the upper bound of the
+ range. eg, if you have an index with 3 fields then you would have:
+ (val1, val2, val3)
+ :return: List of [Document]
+ """
+ raise NotImplementedError(self.get_range_from_index)
+
+ def get_index_keys(self, index_name):
+ """Return all keys under which documents are indexed in this index.
+
+ :param index_name: The index to query
+ :return: [] A list of tuples of indexed keys.
+ """
+ raise NotImplementedError(self.get_index_keys)
+
+ def get_doc_conflicts(self, doc_id):
+ """Get the list of conflicts for the given document.
+
+ The order of the conflicts is such that the first entry is the value
+ that would be returned by "get_doc".
+
+ :return: [doc] A list of the Document entries that are conflicted.
+ """
+ raise NotImplementedError(self.get_doc_conflicts)
+
+ def resolve_doc(self, doc, conflicted_doc_revs):
+ """Mark a document as no longer conflicted.
+
+ We take the list of revisions that the client knows about that it is
+ superseding. This may be a different list from the actual current
+ conflicts, in which case only those are removed as conflicted. This
+ may fail if the conflict list is significantly different from the
+ supplied information. (sync could have happened in the background from
+ the time you GET_DOC_CONFLICTS until the point where you RESOLVE)
+
+ :param doc: A Document with the new content to be inserted.
+ :param conflicted_doc_revs: A list of revisions that the new content
+ supersedes.
+ """
+ raise NotImplementedError(self.resolve_doc)
+
+ def get_sync_target(self):
+ """Return a SyncTarget object, for another u1db to synchronize with.
+
+ :return: An instance of SyncTarget.
+ """
+ raise NotImplementedError(self.get_sync_target)
+
+ def close(self):
+ """Release any resources associated with this database."""
+ raise NotImplementedError(self.close)
+
+ def sync(self, url, creds=None, autocreate=True):
+ """Synchronize documents with remote replica exposed at url.
+
+ :param url: the url of the target replica to sync with.
+ :param creds: optional dictionary giving credentials
+ to authorize the operation with the server. For using OAuth
+ the form of creds is:
+ {'oauth': {
+ 'consumer_key': ...,
+ 'consumer_secret': ...,
+ 'token_key': ...,
+ 'token_secret': ...
+ }}
+ :param autocreate: ask the target to create the db if non-existent.
+ :return: local_gen_before_sync The local generation before the
+ synchronisation was performed. This is useful to pass into
+ whatschanged, if an application wants to know which documents were
+ affected by a synchronisation.
+ """
+ from u1db.sync import Synchronizer
+ from u1db.remote.http_target import HTTPSyncTarget
+ return Synchronizer(self, HTTPSyncTarget(url, creds=creds)).sync(
+ autocreate=autocreate)
+
+ def _get_replica_gen_and_trans_id(self, other_replica_uid):
+ """Return the last known generation and transaction id for the other db
+ replica.
+
+ When you do a synchronization with another replica, the Database keeps
+ track of what generation the other database replica was at, and what
+ the associated transaction id was. This is used to determine what data
+ needs to be sent, and if two databases are claiming to be the same
+ replica.
+
+ :param other_replica_uid: The identifier for the other replica.
+ :return: (gen, trans_id) The generation and transaction id we
+ encountered during synchronization. If we've never synchronized
+ with the replica, this is (0, '').
+ """
+ raise NotImplementedError(self._get_replica_gen_and_trans_id)
+
+ def _set_replica_gen_and_trans_id(self, other_replica_uid,
+ other_generation, other_transaction_id):
+ """Set the last-known generation and transaction id for the other
+ database replica.
+
+ We have just performed some synchronization, and we want to track what
+ generation the other replica was at. See also
+ _get_replica_gen_and_trans_id.
+ :param other_replica_uid: The U1DB identifier for the other replica.
+ :param other_generation: The generation number for the other replica.
+ :param other_transaction_id: The transaction id associated with the
+ generation.
+ """
+ raise NotImplementedError(self._set_replica_gen_and_trans_id)
+
+ def _put_doc_if_newer(self, doc, save_conflict, replica_uid, replica_gen,
+ replica_trans_id=''):
+ """Insert/update document into the database with a given revision.
+
+ This api is used during synchronization operations.
+
+ If a document would conflict and save_conflict is set to True, the
+ content will be selected as the 'current' content for doc.doc_id,
+ even though doc.rev doesn't supersede the currently stored revision.
+ The currently stored document will be added to the list of conflict
+ alternatives for the given doc_id.
+
+ This forces the new content to be 'current' so that we get convergence
+ after synchronizing, even if people don't resolve conflicts. Users can
+ then notice that their content is out of date, update it, and
+ synchronize again. (The alternative is that users could synchronize and
+ think the data has propagated, but their local copy looks fine, and the
+ remote copy is never updated again.)
+
+ :param doc: A Document object
+ :param save_conflict: If this document is a conflict, do you want to
+ save it as a conflict, or just ignore it.
+ :param replica_uid: A unique replica identifier.
+ :param replica_gen: The generation of the replica corresponding to the
+ this document. The replica arguments are optional, but are used
+ during synchronization.
+ :param replica_trans_id: The transaction_id associated with the
+ generation.
+ :return: (state, at_gen) - If we don't have doc_id already,
+ or if doc_rev supersedes the existing document revision,
+ then the content will be inserted, and state is 'inserted'.
+ If doc_rev is less than or equal to the existing revision,
+ then the put is ignored and state is respecitvely 'superseded'
+ or 'converged'.
+ If doc_rev is not strictly superseded or supersedes, then
+ state is 'conflicted'. The document will not be inserted if
+ save_conflict is False.
+ For 'inserted' or 'converged', at_gen is the insertion/current
+ generation.
+ """
+ raise NotImplementedError(self._put_doc_if_newer)
+
+
+class DocumentBase(object):
+ """Container for handling a single document.
+
+ :ivar doc_id: Unique identifier for this document.
+ :ivar rev: The revision identifier of the document.
+ :ivar json_string: The JSON string for this document.
+ :ivar has_conflicts: Boolean indicating if this document has conflicts
+ """
+
+ def __init__(self, doc_id, rev, json_string, has_conflicts=False):
+ self.doc_id = doc_id
+ self.rev = rev
+ if json_string is not None:
+ try:
+ value = json.loads(json_string)
+ except json.JSONDecodeError:
+ raise InvalidJSON
+ if not isinstance(value, dict):
+ raise InvalidJSON
+ self._json = json_string
+ self.has_conflicts = has_conflicts
+
+ def same_content_as(self, other):
+ """Compare the content of two documents."""
+ if self._json:
+ c1 = json.loads(self._json)
+ else:
+ c1 = None
+ if other._json:
+ c2 = json.loads(other._json)
+ else:
+ c2 = None
+ return c1 == c2
+
+ def __repr__(self):
+ if self.has_conflicts:
+ extra = ', conflicted'
+ else:
+ extra = ''
+ return '%s(%s, %s%s, %r)' % (self.__class__.__name__, self.doc_id,
+ self.rev, extra, self.get_json())
+
+ def __hash__(self):
+ raise NotImplementedError(self.__hash__)
+
+ def __eq__(self, other):
+ if not isinstance(other, Document):
+ return NotImplemented
+ return (
+ self.doc_id == other.doc_id and self.rev == other.rev and
+ self.same_content_as(other) and self.has_conflicts ==
+ other.has_conflicts)
+
+ def __lt__(self, other):
+ """This is meant for testing, not part of the official api.
+
+ It is implemented so that sorted([Document, Document]) can be used.
+ It doesn't imply that users would want their documents to be sorted in
+ this order.
+ """
+ # Since this is just for testing, we don't worry about comparing
+ # against things that aren't a Document.
+ return ((self.doc_id, self.rev, self.get_json())
+ < (other.doc_id, other.rev, other.get_json()))
+
+ def get_json(self):
+ """Get the json serialization of this document."""
+ if self._json is not None:
+ return self._json
+ return None
+
+ def get_size(self):
+ """Calculate the total size of the document."""
+ size = 0
+ json = self.get_json()
+ if json:
+ size += len(json)
+ if self.rev:
+ size += len(self.rev)
+ if self.doc_id:
+ size += len(self.doc_id)
+ return size
+
+ def set_json(self, json_string):
+ """Set the json serialization of this document."""
+ if json_string is not None:
+ try:
+ value = json.loads(json_string)
+ except json.JSONDecodeError:
+ raise InvalidJSON
+ if not isinstance(value, dict):
+ raise InvalidJSON
+ self._json = json_string
+
+ def make_tombstone(self):
+ """Make this document into a tombstone."""
+ self._json = None
+
+ def is_tombstone(self):
+ """Return True if the document is a tombstone, False otherwise."""
+ if self._json is not None:
+ return False
+ return True
+
+
+class Document(DocumentBase):
+ """Container for handling a single document.
+
+ :ivar doc_id: Unique identifier for this document.
+ :ivar rev: The revision identifier of the document.
+ :ivar json: The JSON string for this document.
+ :ivar has_conflicts: Boolean indicating if this document has conflicts
+ """
+
+ # The following part of the API is optional: no implementation is forced to
+ # have it but if the language supports dictionaries/hashtables, it makes
+ # Documents a lot more user friendly.
+
+ def __init__(self, doc_id=None, rev=None, json='{}', has_conflicts=False):
+ # TODO: We convert the json in the superclass to check its validity so
+ # we might as well set _content here directly since the price is
+ # already being paid.
+ super(Document, self).__init__(doc_id, rev, json, has_conflicts)
+ self._content = None
+
+ def same_content_as(self, other):
+ """Compare the content of two documents."""
+ if self._json:
+ c1 = json.loads(self._json)
+ else:
+ c1 = self._content
+ if other._json:
+ c2 = json.loads(other._json)
+ else:
+ c2 = other._content
+ return c1 == c2
+
+ def get_json(self):
+ """Get the json serialization of this document."""
+ json_string = super(Document, self).get_json()
+ if json_string is not None:
+ return json_string
+ if self._content is not None:
+ return json.dumps(self._content)
+ return None
+
+ def set_json(self, json):
+ """Set the json serialization of this document."""
+ self._content = None
+ super(Document, self).set_json(json)
+
+ def make_tombstone(self):
+ """Make this document into a tombstone."""
+ self._content = None
+ super(Document, self).make_tombstone()
+
+ def is_tombstone(self):
+ """Return True if the document is a tombstone, False otherwise."""
+ if self._content is not None:
+ return False
+ return super(Document, self).is_tombstone()
+
+ def _get_content(self):
+ """Get the dictionary representing this document."""
+ if self._json is not None:
+ self._content = json.loads(self._json)
+ self._json = None
+ if self._content is not None:
+ return self._content
+ return None
+
+ def _set_content(self, content):
+ """Set the dictionary representing this document."""
+ try:
+ tmp = json.dumps(content)
+ except TypeError:
+ raise InvalidContent(
+ "Can not be converted to JSON: %r" % (content,))
+ if not tmp.startswith('{'):
+ raise InvalidContent(
+ "Can not be converted to a JSON object: %r." % (content,))
+ # We might as well store the JSON at this point since we did the work
+ # of encoding it, and it doesn't lose any information.
+ self._json = tmp
+ self._content = None
+
+ content = property(
+ _get_content, _set_content, doc="Content of the Document.")
+
+ # End of optional part.
+
+
+class SyncTarget(object):
+ """Functionality for using a Database as a synchronization target."""
+
+ def get_sync_info(self, source_replica_uid):
+ """Return information about known state.
+
+ Return the replica_uid and the current database generation of this
+ database, and the last-seen database generation for source_replica_uid
+
+ :param source_replica_uid: Another replica which we might have
+ synchronized with in the past.
+ :return: (target_replica_uid, target_replica_generation,
+ target_trans_id, source_replica_last_known_generation,
+ source_replica_last_known_transaction_id)
+ """
+ raise NotImplementedError(self.get_sync_info)
+
+ def record_sync_info(self, source_replica_uid, source_replica_generation,
+ source_replica_transaction_id):
+ """Record tip information for another replica.
+
+ After sync_exchange has been processed, the caller will have
+ received new content from this replica. This call allows the
+ source replica instigating the sync to inform us what their
+ generation became after applying the documents we returned.
+
+ This is used to allow future sync operations to not need to repeat data
+ that we just talked about. It also means that if this is called at the
+ wrong time, there can be database records that will never be
+ synchronized.
+
+ :param source_replica_uid: The identifier for the source replica.
+ :param source_replica_generation:
+ The database generation for the source replica.
+ :param source_replica_transaction_id: The transaction id associated
+ with the source replica generation.
+ """
+ raise NotImplementedError(self.record_sync_info)
+
+ def sync_exchange(self, docs_by_generation, source_replica_uid,
+ last_known_generation, last_known_trans_id,
+ return_doc_cb, ensure_callback=None):
+ """Incorporate the documents sent from the source replica.
+
+ This is not meant to be called by client code directly, but is used as
+ part of sync().
+
+ This adds docs to the local store, and determines documents that need
+ to be returned to the source replica.
+
+ Documents must be supplied in docs_by_generation paired with
+ the generation of their latest change in order from the oldest
+ change to the newest, that means from the oldest generation to
+ the newest.
+
+ Documents are also returned paired with the generation of
+ their latest change in order from the oldest change to the
+ newest.
+
+ :param docs_by_generation: A list of [(Document, generation,
+ transaction_id)] tuples indicating documents which should be
+ updated on this replica paired with the generation and transaction
+ id of their latest change.
+ :param source_replica_uid: The source replica's identifier
+ :param last_known_generation: The last generation that the source
+ replica knows about this target replica
+ :param last_known_trans_id: The last transaction id that the source
+ replica knows about this target replica
+ :param: return_doc_cb(doc, gen): is a callback
+ used to return documents to the source replica, it will
+ be invoked in turn with Documents that have changed since
+ last_known_generation together with the generation of
+ their last change.
+ :param: ensure_callback(replica_uid): if set the target may create
+ the target db if not yet existent, the callback can then
+ be used to inform of the created db replica uid.
+ :return: new_generation - After applying docs_by_generation, this is
+ the current generation for this replica
+ """
+ raise NotImplementedError(self.sync_exchange)
+
+ def _set_trace_hook(self, cb):
+ """Set a callback that will be invoked to trace database actions.
+
+ The callback will be passed a string indicating the current state, and
+ the sync target object. Implementations do not have to implement this
+ api, it is used by the test suite.
+
+ :param cb: A callable that takes cb(state)
+ """
+ raise NotImplementedError(self._set_trace_hook)
+
+ def _set_trace_hook_shallow(self, cb):
+ """Set a callback that will be invoked to trace database actions.
+
+ Similar to _set_trace_hook, for implementations that don't offer
+ state changes from the inner working of sync_exchange().
+
+ :param cb: A callable that takes cb(state)
+ """
+ self._set_trace_hook(cb)