hoàn thành phần Authentication

backend/app/schemas.py

@@ -0,0 +1,47 @@
+from datetime import datetime
+from pydantic import BaseModel, EmailStr, field_validator
+import re
+
+
+# ── Auth ─────────────────────────────────────────────────────────────────────
+
+class UserRegister(BaseModel):
+    username: str
+    email: EmailStr
+    password: str
+
+    @field_validator("username")
+    @classmethod
+    def username_valid(cls, v: str) -> str:
+        v = v.strip()
+        if not re.match(r"^[A-Za-z0-9_]{3,64}$", v):
+            raise ValueError(
+                "Username must be 3–64 characters, letters/numbers/underscore only."
+            )
+        return v
+
+    @field_validator("password")
+    @classmethod
+    def password_strength(cls, v: str) -> str:
+        if len(v) < 8:
+            raise ValueError("Password must be at least 8 characters.")
+        return v
+
+
+class UserLogin(BaseModel):
+    username: str
+    password: str
+
+
+class UserOut(BaseModel):
+    id: int
+    username: str
+    email: str
+    created_at: datetime
+
+    model_config = {"from_attributes": True}
+
+
+class TokenPayload(BaseModel):
+    sub: int   # user id
+    exp: int