Handle custom formats with fastjsonschema correctly (#158)

Author: s-knibbs

dataclasses_jsonschema/__init__.py

@@ -20,7 +20,7 @@
 
 from .field_types import (  # noqa: F401
     FieldEncoder, DateFieldEncoder, DateTimeFieldEncoder, UuidField, DecimalField,
-    IPv4AddressField, IPv6AddressField, DateTimeField, UUID_REGEX
+    IPv4AddressField, IPv6AddressField, DateTimeField
 )
 from .type_defs import JsonDict, SchemaType, JsonSchemaMeta, _NULL_TYPE, NULL  # noqa: F401
 from .type_hints import get_class_type_hints
@@ -474,8 +474,14 @@ def _validate(cls, data: JsonDict, validate_enums: bool = True):
                 # TODO: Support validating with other schema types
                 schema_validator = cls.__compiled_schema.get(SchemaOptions(DEFAULT_SCHEMA_TYPE, validate_enums))
                 if schema_validator is None:
+                    formats = {}
+                    for encoder in cls._field_encoders.values():
+                        schema = encoder.json_schema
+                        if 'pattern' in schema and 'format' in schema:
+                            formats[schema['format']] = schema['pattern']
+
                     schema_validator = fastjsonschema.compile(
-                        cls.json_schema(validate_enums=validate_enums), formats={'uuid': UUID_REGEX}
+                        cls.json_schema(validate_enums=validate_enums), formats=formats
                     )
                     cls.__compiled_schema[SchemaOptions(DEFAULT_SCHEMA_TYPE, validate_enums)] = schema_validator
                 schema_validator(data)

tests/test_core.py

@@ -978,3 +978,27 @@ class Pet(JsonSchemaMixin):
     schema = Pet.json_schema(embeddable=True, schema_type=SchemaType.OPENAPI_3)
     assert schema['Pet']['x-module-name'] == 'tests.test_core'
     assert schema['Pet']['properties']['type']['x-module-name'] == 'tests.test_core'
+
+
+def test_custom_format():
+    Slug = NewType('Slug', str)
+
+    class SlugField(FieldEncoder[Slug, str]):
+
+        @property
+        def json_schema(self) -> JsonDict:
+            return {
+                'type': 'string',
+                'format': 'slug',
+                'pattern': r'^[a-z0-9\-]+$',
+            }
+
+    JsonSchemaMixin.register_field_encoders({Slug: SlugField()})
+
+    @dataclass
+    class Post(JsonSchemaMixin):
+        slug: Slug
+        content: str
+
+    post = Post.from_dict({"content": "Lorem ipsum dolor ...", "slug": "some-post"})
+    assert post.slug == Slug("some-post")