Move the BaseModel subclass to synapse.rest

and give it a rename to be a bit more specific

synapse/rest/__init__.py

@@ -14,6 +14,8 @@
 # limitations under the License.
 from typing import TYPE_CHECKING, Callable
 
+from pydantic import BaseModel, Extra
+
 from synapse.http.server import HttpServer, JsonResource
 from synapse.rest import admin
 from synapse.rest.client import (
@@ -130,3 +132,25 @@ def register_servlets(client_resource: HttpServer, hs: "HomeServer") -> None:
 
         # unstable
         mutual_rooms.register_servlets(hs, client_resource)
+
+
+class RequestBodyModel(BaseModel):
+    """A custom version of Pydantic's BaseModel which
+
+     - ignores unknown fields and
+     - does not allow fields to be overwritten after construction,
+
+    but otherwise uses Pydantic's default behaviour.
+
+    Ignoring unknown fields is a useful default. It means that clients can provide
+    unstable field not known to the server without the request being refused outright.
+
+    Subclassing in this way is recommended by
+    https://pydantic-docs.helpmanual.io/usage/model_config/#change-behaviour-globally
+    """
+
+    class Config:
+        # By default, ignore fields that we don't recognise.
+        extra = Extra.ignore
+        # By default, don't allow fields to be reassigned after parsing.
+        allow_mutation = False

synapse/rest/client/account.py

@@ -42,8 +42,9 @@
 from synapse.http.site import SynapseRequest
 from synapse.metrics import threepid_send_requests
 from synapse.push.mailer import Mailer
+from synapse.rest import RequestBodyModel
 from synapse.rest.client.models import AuthenticationData, EmailRequestTokenBody
-from synapse.types import JsonDict, SynapseBaseModel
+from synapse.types import JsonDict
 from synapse.util.msisdn import phone_number_to_msisdn
 from synapse.util.stringutils import assert_valid_client_secret, random_string
 from synapse.util.threepids import check_3pid_allowed, validate_email
@@ -159,7 +160,7 @@ def __init__(self, hs: "HomeServer"):
         self.password_policy_handler = hs.get_password_policy_handler()
         self._set_password_handler = hs.get_set_password_handler()
 
-    class PostBody(SynapseBaseModel):
+    class PostBody(RequestBodyModel):
         auth: Optional[AuthenticationData] = None
         logout_devices: StrictBool = True
         if TYPE_CHECKING:
@@ -293,7 +294,7 @@ def __init__(self, hs: "HomeServer"):
         self.auth_handler = hs.get_auth_handler()
         self._deactivate_account_handler = hs.get_deactivate_account_handler()
 
-    class PostBody(SynapseBaseModel):
+    class PostBody(RequestBodyModel):
         auth: Optional[AuthenticationData] = None
         id_server: Optional[StrictStr] = None
         # Not specced, see https://github.com/matrix-org/matrix-spec/issues/297

synapse/rest/client/models.py

@@ -15,19 +15,28 @@
 
 from pydantic import Extra, StrictInt, StrictStr, constr, validator
 
-from synapse.types import SynapseBaseModel
+from synapse.rest import RequestBodyModel
 from synapse.util.threepids import validate_email
 
 
-class AuthenticationData(SynapseBaseModel):
+class AuthenticationData(RequestBodyModel):
+    """
+    Data used during user-interactive authentication.
+
+    (The name "Authentication Data" is taken directly from the spec.)
+
+    Additional keys will be present, depending on the `type` field. Use `.dict()` to
+    access them.
+    """
+
     class Config:
         extra = Extra.allow
 
     session: Optional[StrictStr] = None
     type: Optional[StrictStr] = None
 
 
-class EmailRequestTokenBody(SynapseBaseModel):
+class EmailRequestTokenBody(RequestBodyModel):
     if TYPE_CHECKING:
         client_secret: StrictStr
     else:

synapse/types.py

@@ -35,7 +35,6 @@
 
 import attr
 from frozendict import frozendict
-from pydantic import BaseModel, Extra
 from signedjson.key import decode_verify_key_bytes
 from signedjson.types import VerifyKey
 from typing_extensions import Final, TypedDict
@@ -921,22 +920,3 @@ class UserProfile(TypedDict):
 class RetentionPolicy:
     min_lifetime: Optional[int] = None
     max_lifetime: Optional[int] = None
-
-
-class SynapseBaseModel(BaseModel):
-    """A custom version of Pydantic's BaseModel.
-
-    This
-     - ignores unknown fields and
-     - does not allow fields to be overwritten after construction,
-    but otherwise uses Pydantic's default behaviour.
-
-    Subclassing in this way is recommended by
-    https://pydantic-docs.helpmanual.io/usage/model_config/#change-behaviour-globally
-    """
-
-    class Config:
-        # By default, ignore fields that we don't recognise.
-        extra = Extra.ignore
-        # By default, don't allow fields to be reassigned after parsing.
-        allow_mutation = False