Move source files to proper subdirectory.

1 files changed, 270 insertions, 0 deletions

diff --git a/src/leap/soledad/backends/couch.py b/src/leap/soledad/backends/couch.py
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+"""A U1DB backend that uses CouchDB as its persistence layer."""
+
+# general imports
+import uuid
+from base64 import b64encode, b64decode
+import re
+# u1db
+from u1db import errors
+from u1db.sync import LocalSyncTarget
+from u1db.backends.inmemory import InMemoryIndex
+from u1db.remote.server_state import ServerState
+from u1db.errors import DatabaseDoesNotExist
+# couchdb
+from couchdb.client import Server, Document as CouchDocument
+from couchdb.http import ResourceNotFound
+# leap
+from leap.soledad.backends.objectstore import (
+    ObjectStoreDatabase,
+    ObjectStoreSyncTarget,
+)
+from leap.soledad.backends.leap_backend import LeapDocument
+
+try:
+    import simplejson as json
+except ImportError:
+    import json  # noqa
+
+
+class InvalidURLError(Exception):
+    """Exception raised when Soledad encounters a malformed URL."""
+    pass
+
+
+class CouchDatabase(ObjectStoreDatabase):
+    """A U1DB backend that uses Couch as its persistence layer."""
+
+    @classmethod
+    def open_database(cls, url, create):
+        """Open a U1DB database using CouchDB as backend."""
+        # get database from url
+        m = re.match('(^https?://[^/]+)/(.+)$', url)
+        if not m:
+            raise InvalidURLError
+        url = m.group(1)
+        dbname = m.group(2)
+        server = Server(url=url)
+        try:
+            server[dbname]
+        except ResourceNotFound:
+            if not create:
+                raise DatabaseDoesNotExist()
+        return cls(url, dbname)
+
+    def __init__(self, url, database, replica_uid=None, full_commit=True,
+                 session=None):
+        """Create a new Couch data container."""
+        self._url = url
+        self._full_commit = full_commit
+        self._session = session
+        self._server = Server(url=self._url,
+                              full_commit=self._full_commit,
+                              session=self._session)
+        self._dbname = database
+        # this will ensure that transaction and sync logs exist and are
+        # up-to-date.
+        try:
+            self._database = self._server[database]
+        except ResourceNotFound:
+            self._server.create(database)
+            self._database = self._server[database]
+        super(CouchDatabase, self).__init__(replica_uid=replica_uid,
+                                            document_factory=LeapDocument)
+
+    #-------------------------------------------------------------------------
+    # methods from Database
+    #-------------------------------------------------------------------------
+
+    def _get_doc(self, doc_id, check_for_conflicts=False):
+        """Get just the document content, without fancy handling."""
+        cdoc = self._database.get(doc_id)
+        if cdoc is None:
+            return None
+        has_conflicts = False
+        if check_for_conflicts:
+            has_conflicts = self._has_conflicts(doc_id)
+        doc = self._factory(
+            doc_id=doc_id,
+            rev=cdoc['u1db_rev'],
+            has_conflicts=has_conflicts)
+        contents = self._database.get_attachment(cdoc, 'u1db_json')
+        if contents:
+            doc.content = json.loads(contents.getvalue())
+        else:
+            doc.make_tombstone()
+        return doc
+
+    def get_all_docs(self, include_deleted=False):
+        """Get the JSON content for all documents in the database."""
+        generation = self._get_generation()
+        results = []
+        for doc_id in self._database:
+            if doc_id == self.U1DB_DATA_DOC_ID:
+                continue
+            doc = self._get_doc(doc_id, check_for_conflicts=True)
+            if doc.content is None and not include_deleted:
+                continue
+            results.append(doc)
+        return (generation, results)
+
+    def _put_doc(self, doc):
+        """Store document in database."""
+        # prepare couch's Document
+        cdoc = CouchDocument()
+        cdoc['_id'] = doc.doc_id
+        # we have to guarantee that couch's _rev is cosistent
+        old_cdoc = self._database.get(doc.doc_id)
+        if old_cdoc is not None:
+            cdoc['_rev'] = old_cdoc['_rev']
+        # store u1db's rev
+        cdoc['u1db_rev'] = doc.rev
+        # save doc in db
+        self._database.save(cdoc)
+        # store u1db's content as json string
+        if not doc.is_tombstone():
+            self._database.put_attachment(cdoc, doc.get_json(),
+                                          filename='u1db_json')
+        else:
+            self._database.delete_attachment(cdoc, 'u1db_json')
+
+    def get_sync_target(self):
+        """
+        Return a SyncTarget object, for another u1db to synchronize with.
+        """
+        return CouchSyncTarget(self)
+
+    def create_index(self, index_name, *index_expressions):
+        """
+        Create a named index, which can then be queried for future lookups.
+        """
+        if index_name in self._indexes:
+            if self._indexes[index_name]._definition == list(
+                    index_expressions):
+                return
+            raise errors.IndexNameTakenError
+        index = InMemoryIndex(index_name, list(index_expressions))
+        for doc_id in self._database:
+            if doc_id == self.U1DB_DATA_DOC_ID:
+                continue
+            doc = self._get_doc(doc_id)
+            if doc.content is not None:
+                index.add_json(doc_id, doc.get_json())
+        self._indexes[index_name] = index
+        # save data in object store
+        self._store_u1db_data()
+
+    def close(self):
+        """Release any resources associated with this database."""
+        # TODO: fix this method so the connection is properly closed and
+        # test_close (+tearDown, which deletes the db) works without problems.
+        self._url = None
+        self._full_commit = None
+        self._session = None
+        #self._server = None
+        self._database = None
+        return True
+
+    def sync(self, url, creds=None, autocreate=True):
+        """Synchronize documents with remote replica exposed at url."""
+        from u1db.sync import Synchronizer
+        return Synchronizer(self, CouchSyncTarget(url, creds=creds)).sync(
+            autocreate=autocreate)
+
+    #-------------------------------------------------------------------------
+    # methods from ObjectStoreDatabase
+    #-------------------------------------------------------------------------
+
+    def _init_u1db_data(self):
+        if self._replica_uid is None:
+            self._replica_uid = uuid.uuid4().hex
+        doc = self._factory(doc_id=self.U1DB_DATA_DOC_ID)
+        doc.content = {'transaction_log': [],
+                       'conflicts': b64encode(json.dumps({})),
+                       'other_generations': {},
+                       'indexes': b64encode(json.dumps({})),
+                       'replica_uid': self._replica_uid}
+        self._put_doc(doc)
+
+    def _fetch_u1db_data(self):
+        # retrieve u1db data from couch db
+        cdoc = self._database.get(self.U1DB_DATA_DOC_ID)
+        jsonstr = self._database.get_attachment(cdoc, 'u1db_json').getvalue()
+        content = json.loads(jsonstr)
+        # set u1db database info
+        #self._sync_log = content['sync_log']
+        self._transaction_log = content['transaction_log']
+        self._conflicts = json.loads(b64decode(content['conflicts']))
+        self._other_generations = content['other_generations']
+        self._indexes = self._load_indexes_from_json(
+            b64decode(content['indexes']))
+        self._replica_uid = content['replica_uid']
+        # save couch _rev
+        self._couch_rev = cdoc['_rev']
+
+    def _store_u1db_data(self):
+        doc = self._factory(doc_id=self.U1DB_DATA_DOC_ID)
+        doc.content = {
+            'transaction_log': self._transaction_log,
+            # Here, the b64 encode ensures that document content
+            # does not cause strange behaviour in couchdb because
+            # of encoding.
+            'conflicts': b64encode(json.dumps(self._conflicts)),
+            'other_generations': self._other_generations,
+            'indexes': b64encode(self._dump_indexes_as_json()),
+            'replica_uid': self._replica_uid,
+            '_rev': self._couch_rev}
+        self._put_doc(doc)
+
+    #-------------------------------------------------------------------------
+    # Couch specific methods
+    #-------------------------------------------------------------------------
+
+    def delete_database(self):
+        """Delete a U1DB CouchDB database."""
+        del(self._server[self._dbname])
+
+    def _dump_indexes_as_json(self):
+        indexes = {}
+        for name, idx in self._indexes.iteritems():
+            indexes[name] = {}
+            for attr in ['name', 'definition', 'values']:
+                indexes[name][attr] = getattr(idx, '_' + attr)
+        return json.dumps(indexes)
+
+    def _load_indexes_from_json(self, indexes):
+        dict = {}
+        for name, idx_dict in json.loads(indexes).iteritems():
+            idx = InMemoryIndex(name, idx_dict['definition'])
+            idx._values = idx_dict['values']
+            dict[name] = idx
+        return dict
+
+
+class CouchSyncTarget(ObjectStoreSyncTarget):
+    pass
+
+
+class CouchServerState(ServerState):
+    """Inteface of the WSGI server with the CouchDB backend."""
+
+    def __init__(self, couch_url):
+        self.couch_url = couch_url
+
+    def open_database(self, dbname):
+        """Open a database at the given location."""
+        # TODO: open couch
+        from leap.soledad.backends.couch import CouchDatabase
+        return CouchDatabase.open_database(self.couch_url + '/' + dbname,
+                                           create=False)
+
+    def ensure_database(self, dbname):
+        """Ensure database at the given location."""
+        from leap.soledad.backends.couch import CouchDatabase
+        db = CouchDatabase.open_database(self.couch_url + '/' + dbname,
+                                         create=True)
+        return db, db._replica_uid
+
+    def delete_database(self, dbname):
+        """Delete database at the given location."""
+        from leap.soledad.backends.couch import CouchDatabase
+        CouchDatabase.delete_database(self.couch_url + '/' + dbname)