schema cache: Do not read fingerprint and format from cache

Fingerprint can be obtained from schema filename of from ServerInfo
instance. Use FORMAT in path to avoid openening schema just to read its
format.

https://fedorahosted.org/freeipa/ticket/6048

Reviewed-By: Jan Cholasta <jcholast@redhat.com>

ipaclient/remote_plugins/schema.py

@@ -20,6 +20,7 @@ from ipalib.frontend import Object
 from ipalib.output import Output
 from ipalib.parameters import DefaultFrom, Flag, Password, Str
 from ipaplatform.paths import paths
+from ipapython.ipautil import fsdecode
 from ipapython.dn import DN
 from ipapython.dnsutil import DNSName
 from ipapython.ipa_log_manager import log_mgr
@@ -370,7 +371,7 @@ class Schema(object):
 
     """
     namespaces = {'classes', 'commands', 'topics'}
-    _DIR = os.path.join(paths.USER_CACHE_PATH, 'ipa', 'schema')
+    _DIR = os.path.join(paths.USER_CACHE_PATH, 'ipa', 'schema', FORMAT)
 
     def __init__(self, api, server_info, client):
         self._dict = {}
@@ -416,34 +417,14 @@ class Schema(object):
         path = os.path.join(self._DIR, filename)
         return _LockedZipFile(path, mode)
 
-    def _get_schema_fingerprint(self, schema):
-        try:
-            fmt = json.loads(schema.read('format'))
-        except KeyError:
-            fmt = '0'
-
-        if fmt != FORMAT:
-            raise RuntimeError('invalid format')
-
-        return json.loads(schema.read('fingerprint'))
-
     def _fetch(self, client):
         if not client.isconnected():
             client.connect(verbose=False)
 
-        fps = []
         try:
-            files = os.listdir(self._DIR)
+            fps = [fsdecode(f) for f in os.listdir(self._DIR)]
         except EnvironmentError:
-            pass
-        else:
-            for filename in files:
-                try:
-                    with self._open_schema(filename, 'r') as schema:
-                        fps.append(
-                            unicode(self._get_schema_fingerprint(schema)))
-                except Exception:
-                    continue
+            fps = []
 
         kwargs = {u'version': u'2.170'}
         if fps:
@@ -470,8 +451,6 @@ class Schema(object):
 
     def _read_schema(self):
         with self._open_schema(self._fingerprint, 'r') as schema:
-            self._dict['fingerprint'] = self._get_schema_fingerprint(schema)
-
             for name in schema.namelist():
                 ns, _slash, key = name.partition('/')
                 if ns in self.namespaces:
@@ -559,7 +538,7 @@ def get_package(api, server_info, client):
         schema = Schema(api, server_info, client)
         object.__setattr__(api, '_schema', schema)
 
-    fingerprint = str(schema['fingerprint'])
+    fingerprint = str(server_info['fingerprint'])
     package_name = '{}${}'.format(__name__, fingerprint)
     package_dir = '{}${}'.format(os.path.splitext(__file__)[0], fingerprint)