Improve Pydantic support

CHANGELOG.rst

@@ -5,6 +5,22 @@ Changelog
 
 Versions follow `CalVer <http://www.calver.org/>`_ with the scheme ``YY.0M.Micro``.
 
+`2024.05.0`_ - 2024/05/07
+-------------------------
+Fixed
+~~~~~
+* Loading JSON data into a Pydantic model with an ``IBAN``-field (``Model.model_validate_json()``)
+  was previously broken and has been fixed now.
+
+Added
+~~~~~
+* JSON schema generation for Pydantic models.
+
+Changed
+~~~~~~~
+* Updated bank registries.
+
+
 `2024.04.0`_ - 2024/04/18
 -------------------------
 Added
@@ -564,6 +580,7 @@ Added
 * Added :attr:`.BIC.country` and :attr:`.IBAN.country`.
 
 
+.. _2024.05.0: https://github.com/mdomke/schwifty/compare/2024.04.0...2024.05.0
 .. _2024.04.0: https://github.com/mdomke/schwifty/compare/2023.01.1...2024.04.0
 .. _2024.01.1: https://github.com/mdomke/schwifty/compare/2023.11.2...2024.01.1
 .. _2023.11.2: https://github.com/mdomke/schwifty/compare/2023.11.1...2023.11.2

schwifty/iban.py

@@ -19,6 +19,9 @@
 
 if TYPE_CHECKING:
     from pydantic import GetCoreSchemaHandler
+    from pydantic import GetJsonSchemaHandler
+    from pydantic import ValidatorFunctionWrapHandler
+    from pydantic.json_schema import JsonSchemaValue
     from pydantic_core import CoreSchema
 
 
@@ -359,16 +362,44 @@ def bank_short_name(self) -> str | None:
         return self.bban.bank_short_name
 
     @classmethod
-    def __get_pydantic_core_schema__(cls, source: Any, handler: GetCoreSchemaHandler) -> CoreSchema:
+    def __get_pydantic_core_schema__(
+        cls, source: type[Any], handler: GetCoreSchemaHandler
+    ) -> CoreSchema:
         from pydantic_core import core_schema
 
-        return core_schema.union_schema(
-            [
-                core_schema.is_instance_schema(IBAN),
-                core_schema.no_info_plain_validator_function(IBAN),
-            ]
+        return core_schema.no_info_wrap_validator_function(
+            cls._pydantic_validate,
+            core_schema.union_schema(
+                [
+                    core_schema.is_instance_schema(IBAN),
+                    core_schema.no_info_plain_validator_function(IBAN),
+                    core_schema.str_schema(max_length=34),
+                ]
+            ),
+            serialization=core_schema.to_string_ser_schema(
+                when_used="json-unless-none",
+            ),
         )
 
+    @classmethod
+    def __get_pydantic_json_schema__(
+        cls, core_schema: CoreSchema, handler: GetJsonSchemaHandler
+    ) -> JsonSchemaValue:
+        json_schema = handler(core_schema)
+        json_schema = handler.resolve_ref_schema(json_schema)
+        json_schema["title"] = "IBAN"
+        return json_schema
+
+    @classmethod
+    def _pydantic_validate(cls, value: Any, handler: ValidatorFunctionWrapHandler) -> Any:
+        from pydantic_core import PydanticCustomError
+
+        try:
+            iban = cls(value)
+        except exceptions.SchwiftyException as err:
+            raise PydanticCustomError("iban_format", str(err)) from err
+        return handler(iban)
+
 
 def add_bban_regex(country: str, spec: dict) -> dict:
     bban_spec = spec["bban_spec"]

tests/test_iban.py

@@ -368,6 +368,21 @@ class Model(BaseModel):
 
     model = Model(iban="GL89 6471 0001 0002 06")  # type: ignore[arg-type]
     assert isinstance(model.iban, IBAN)
+    assert model.model_dump() == {"iban": model.iban}
 
-    with pytest.raises(ValidationError):
+    with pytest.raises(ValidationError) as err:
         Model(iban="GB00 HLFX 1101 6111 4553 65")  # type: ignore[arg-type]
+    assert len(err.value.errors()) == 1
+    error = err.value.errors()[0]
+    assert error["type"] == "iban_format"
+    assert error["msg"] == "Invalid checksum digits"
+    assert error["input"] == "GB00 HLFX 1101 6111 4553 65"
+
+    json_schema = model.model_json_schema()
+    assert json_schema["properties"]["iban"] == {"maxLength": 34, "title": "IBAN", "type": "string"}
+
+    dumped = model.model_dump_json()
+    assert dumped == '{"iban":"GL8964710001000206"}'
+
+    loaded = Model.model_validate_json(dumped)
+    assert loaded == model