diff --git a/lbrynet/metadata/StructuredDict.py b/lbrynet/metadata/StructuredDict.py
new file mode 100644
index 000000000..d1015b4bc
--- /dev/null
+++ b/lbrynet/metadata/StructuredDict.py
@@ -0,0 +1,57 @@
+import jsonschema
+import logging
+
+from jsonschema import ValidationError
+
+log = logging.getLogger(__name__)
+
+
+class StructuredDict(dict):
+ """
+ A dictionary that enforces a structure specified by a schema, and supports
+ migration between different versions of the schema.
+ """
+
+ # To be specified in sub-classes, an array in the format
+ # [(version, schema, migration), ...]
+ _versions = []
+
+ # Used internally to allow schema lookups by version number
+ _schemas = {}
+
+ version = None
+
+ def __init__(self, value, starting_version, migrate=True, target_version=None):
+ dict.__init__(self, value)
+
+ self.version = starting_version
+ self._schemas = dict([(version, schema) for (version, schema, _) in self._versions])
+
+ self.validate(starting_version)
+
+ if migrate:
+ self.migrate(target_version)
+
+ def validate(self, version):
+ jsonschema.validate(self, self._schemas[version])
+
+ def migrate(self, target_version=None):
+ if target_version:
+ assert self._versions.index(target_version) > self.versions.index(self.version), "Current version is above target version"
+
+ above_starting_version = False
+ for version, schema, migration in self._versions:
+ if not above_starting_version:
+ if version == self.version:
+ above_starting_version = True
+ continue
+
+ migration()
+ try:
+ self.validate(version)
+ except ValidationError as e:
+ raise ValidationError, "Could not migrate to version %s due to validation error: %s" % (version, e.message)
+
+ self.version = version
+ if target_version and version == target_version:
+ break
diff --git a/lbrynet/metadata/Validator.py b/lbrynet/metadata/Validator.py
deleted file mode 100644
index b08ed64e2..000000000
--- a/lbrynet/metadata/Validator.py
+++ /dev/null
@@ -1,155 +0,0 @@
-import json
-import logging
-from copy import deepcopy
-from distutils.version import StrictVersion
-from lbrynet.core.utils import version_is_greater_than
-
-log = logging.getLogger(__name__)
-
-
-def skip_validate(value):
- return True
-
-
-def processor(cls):
- for methodname in dir(cls):
- method = getattr(cls, methodname)
- if hasattr(method, 'cmd_name'):
- cls.commands.update({method.cmd_name: methodname})
- return cls
-
-
-def cmd(cmd_name):
- def wrapper(func):
- func.cmd_name = cmd_name
- return func
- return wrapper
-
-
-@processor
-class Validator(dict):
- """
- Base class for validated dictionaries
- """
-
- # override these
- current_version = None
- versions = {}
- migrations = []
-
- # built in commands
- DO_NOTHING = "do_nothing"
- UPDATE = "update_key"
- IF_KEY = "if_key"
- REQUIRE = "require"
- SKIP = "skip"
- OPTIONAL = "optional"
- LOAD = "load"
- IF_VAL = "if_val"
-
- commands = {}
-
- @classmethod
- def load_from_hex(cls, hex_val):
- return cls(json.loads(hex_val.decode('hex')))
-
- @classmethod
- def validate(cls, value):
- if cls(value):
- return True
- else:
- return False
-
- def __init__(self, value, process_now=False):
- dict.__init__(self)
- self._skip = []
- value_to_load = deepcopy(value)
- if process_now:
- self.process(value_to_load)
- self._verify_value(value_to_load)
- self.version = self.get('ver', "0.0.1")
-
- def process(self, value):
- if self.migrations is not None:
- self._migrate_value(value)
-
- @cmd(DO_NOTHING)
- def _do_nothing(self):
- pass
-
- @cmd(SKIP)
- def _add_to_skipped(self, rx_value, key):
- if key not in self._skip:
- self._skip.append(key)
-
- @cmd(UPDATE)
- def _update(self, rx_value, old_key, new_key):
- rx_value.update({new_key: rx_value.pop(old_key)})
-
- @cmd(IF_KEY)
- def _if_key(self, rx_value, key, if_true, if_else):
- if key in rx_value:
- return self._handle(if_true, rx_value)
- return self._handle(if_else, rx_value)
-
- @cmd(IF_VAL)
- def _if_val(self, rx_value, key, val, if_true, if_else):
- if key in rx_value:
- if rx_value[key] == val:
- return self._handle(if_true, rx_value)
- return self._handle(if_else, rx_value)
-
- @cmd(LOAD)
- def _load(self, rx_value, key, value):
- rx_value.update({key: value})
-
- @cmd(REQUIRE)
- def _require(self, rx_value, key, validator=None):
- if key not in self._skip:
- assert key in rx_value, "Key is missing: %s" % key
- if isinstance(validator, type):
- assert isinstance(rx_value[key], validator), "%s: %s isn't required %s" % (key, type(rx_value[key]), validator)
- elif callable(validator):
- assert validator(rx_value[key]), "Failed to validate %s" % key
- self.update({key: rx_value.pop(key)})
-
- @cmd(OPTIONAL)
- def _optional(self, rx_value, key, validator=None):
- if key in rx_value and key not in self._skip:
- if isinstance(validator, type):
- assert isinstance(rx_value[key], validator), "%s type %s isn't required %s" % (key, type(rx_value[key]), validator)
- elif callable(validator):
- assert validator(rx_value[key]), "Failed to validate %s" % key
- self.update({key: rx_value.pop(key)})
-
- def _handle(self, cmd_tpl, value):
- if cmd_tpl == Validator.DO_NOTHING:
- return
- command = cmd_tpl[0]
- f = getattr(self, self.commands[command])
- if len(cmd_tpl) > 1:
- args = (value,) + cmd_tpl[1:]
- f(*args)
- else:
- f()
-
- def _load_revision(self, version, value):
- for k in self.versions[version]:
- self._handle(k, value)
-
- def _verify_value(self, value):
- val_ver = value.get('ver', "0.0.1")
- # verify version requirements in reverse order starting from the version asserted in the value
- versions = sorted([v for v in self.versions if not version_is_greater_than(v, val_ver)], key=StrictVersion, reverse=True)
- for version in versions:
- self._load_revision(version, value)
- assert value == {} or value.keys() == self._skip, "Unknown keys: %s" % json.dumps(value)
-
- def _migrate_value(self, value):
- for migration in self.migrations:
- self._run_migration(migration, value)
-
- def _run_migration(self, commands, value):
- for cmd in commands:
- self._handle(cmd, value)
-
diff --git a/setup.py b/setup.py
index 87b68a60c..c93a67812 100644
--- a/setup.py
+++ b/setup.py
@@ -40,6 +40,7 @@ requires = [
'lbryum',
'jsonrpc',
'simplejson',
+ 'jsonschema',
'appdirs',
'six==1.9.0',
'base58',