First version

project/api/schemas.py

@@ -0,0 +1,29 @@
+from typing import Annotated
+
+from pydantic import BaseModel, Field
+
+
+NanoID = Annotated[
+    str, Field(min_length=21, max_length=21, pattern="^[A-Za-z0-9_-]{21}$")
+]
+"""A nanoid identifier type for pydantic models.
+
+Example:
+```
+from pydantic import BaseModel
+
+from project.api.schemas import NanoID
+
+
+class BookSchema(BaseModel):
+    id: NanoID
+    title: str
+```
+"""
+
+
+class ErrorSchema(BaseModel):
+    """A standard error response schema."""
+
+    title: str
+    message: str