diff options
Diffstat (limited to 'backends/leap_backend.py')
| -rw-r--r-- | backends/leap_backend.py | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/backends/leap_backend.py b/backends/leap_backend.py new file mode 100644 index 00000000..ced8734c --- /dev/null +++ b/backends/leap_backend.py @@ -0,0 +1,174 @@ +try: + import simplejson as json +except ImportError: + import json # noqa + +from u1db import Document +from u1db.remote.http_target import HTTPSyncTarget +from u1db.remote.http_database import HTTPDatabase +from leap.soledad.util import GPGWrapper + + +class NoDefaultKey(Exception): + pass + +class NoSoledadInstance(Exception): + pass + + +class LeapDocument(Document): + """ + LEAP Documents are standard u1db documents with cabability of returning an + encrypted version of the document json string as well as setting document + content based on an encrypted version of json string. + """ + + def __init__(self, doc_id=None, rev=None, json='{}', has_conflicts=False, + encrypted_json=None, soledad=None): + super(LeapDocument, self).__init__(doc_id, rev, json, has_conflicts) + self._soledad = soledad + if encrypted_json: + self.set_encrypted_json(encrypted_json) + + def get_encrypted_json(self): + """ + Returns document's json serialization encrypted with user's public key. + """ + if not self._soledad: + raise NoSoledadInstance() + ciphertext = self._soledad.encrypt_symmetric(self.doc_id, self.get_json()) + return json.dumps({'_encrypted_json' : ciphertext}) + + def set_encrypted_json(self, encrypted_json): + """ + Set document's content based on encrypted version of json string. + """ + if not self._soledad: + raise NoSoledadInstance() + ciphertext = json.loads(encrypted_json)['_encrypted_json'] + plaintext = self._soledad.decrypt_symmetric(self.doc_id, ciphertext) + return self.set_json(plaintext) + + +class LeapDatabase(HTTPDatabase): + """Implement the HTTP remote database API to a Leap server.""" + + def __init__(self, url, document_factory=None, creds=None, soledad=None): + super(LeapDatabase, self).__init__(url, creds=creds) + self._soledad = soledad + self._factory = LeapDocument + + @staticmethod + def open_database(url, create): + db = LeapDatabase(url) + db.open(create) + return db + + @staticmethod + def delete_database(url): + db = LeapDatabase(url) + db._delete() + db.close() + + def get_sync_target(self): + st = LeapSyncTarget(self._url.geturl()) + st._creds = self._creds + return st + + def create_doc_from_json(self, content, doc_id=None): + if doc_id is None: + doc_id = self._allocate_doc_id() + res, headers = self._request_json('PUT', ['doc', doc_id], {}, + content, 'application/json') + new_doc = self._factory(doc_id, res['rev'], content, soledad=self._soledad) + return new_doc + + +class LeapSyncTarget(HTTPSyncTarget): + + def __init__(self, url, creds=None, soledad=None): + super(LeapSyncTarget, self).__init__(url, creds) + self._soledad = soledad + + def _parse_sync_stream(self, data, return_doc_cb, ensure_callback=None): + """ + Does the same as parent's method but ensures incoming content will be + decrypted. + """ + parts = data.splitlines() # one at a time + if not parts or parts[0] != '[': + raise BrokenSyncStream + data = parts[1:-1] + comma = False + if data: + line, comma = utils.check_and_strip_comma(data[0]) + res = json.loads(line) + if ensure_callback and 'replica_uid' in res: + ensure_callback(res['replica_uid']) + for entry in data[1:]: + if not comma: # missing in between comma + raise BrokenSyncStream + line, comma = utils.check_and_strip_comma(entry) + entry = json.loads(line) + # decrypt after receiving from server. + doc = LeapDocument(entry['id'], entry['rev'], + encrypted_json=entry['content'], + soledad=self._soledad) + return_doc_cb(doc, entry['gen'], entry['trans_id']) + if parts[-1] != ']': + try: + partdic = json.loads(parts[-1]) + except ValueError: + pass + else: + if isinstance(partdic, dict): + self._error(partdic) + raise BrokenSyncStream + if not data or comma: # no entries or bad extra comma + raise BrokenSyncStream + return res + + def sync_exchange(self, docs_by_generations, source_replica_uid, + last_known_generation, last_known_trans_id, + return_doc_cb, ensure_callback=None): + """ + Does the same as parent's method but encrypts content before syncing. + """ + self._ensure_connection() + if self._trace_hook: # for tests + self._trace_hook('sync_exchange') + url = '%s/sync-from/%s' % (self._url.path, source_replica_uid) + self._conn.putrequest('POST', url) + self._conn.putheader('content-type', 'application/x-u1db-sync-stream') + for header_name, header_value in self._sign_request('POST', url, {}): + self._conn.putheader(header_name, header_value) + entries = ['['] + size = 1 + + def prepare(**dic): + entry = comma + '\r\n' + json.dumps(dic) + entries.append(entry) + return len(entry) + + comma = '' + size += prepare( + last_known_generation=last_known_generation, + last_known_trans_id=last_known_trans_id, + ensure=ensure_callback is not None) + comma = ',' + for doc, gen, trans_id in docs_by_generations: + # encrypt before sending to server. + size += prepare(id=doc.doc_id, rev=doc.rev, + content=doc.get_encrypted_json(), + gen=gen, trans_id=trans_id) + entries.append('\r\n]') + size += len(entries[-1]) + self._conn.putheader('content-length', str(size)) + self._conn.endheaders() + for entry in entries: + self._conn.send(entry) + entries = None + data, _ = self._response() + res = self._parse_sync_stream(data, return_doc_cb, ensure_callback) + data = None + return res['new_generation'], res['new_transaction_id'] |