首个可运行的版本

backend/app/models/friend_request.py

@@ -0,0 +1,28 @@
+"""好友请求模型"""
+
+from datetime import datetime, timezone
+
+from sqlalchemy import String, DateTime, ForeignKey
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from app.database import Base
+
+
+class FriendRequest(Base):
+    __tablename__ = "friend_requests"
+
+    id: Mapped[str] = mapped_column(String(36), primary_key=True)
+    from_user_id: Mapped[str] = mapped_column(
+        String(36), ForeignKey("users.id", ondelete="CASCADE"), nullable=False
+    )
+    to_user_id: Mapped[str] = mapped_column(
+        String(36), ForeignKey("users.id", ondelete="CASCADE"), nullable=False
+    )
+    message: Mapped[str | None] = mapped_column(String(200), nullable=True)  # 验证消息
+    status: Mapped[str] = mapped_column(String(20), default="pending")  # pending / accepted / rejected
+    created_at: Mapped[datetime] = mapped_column(DateTime, default=lambda: datetime.utcnow())
+    responded_at: Mapped[datetime | None] = mapped_column(DateTime, nullable=True)
+
+    # 关系
+    from_user = relationship("User", foreign_keys=[from_user_id], back_populates="sent_requests")
+    to_user = relationship("User", foreign_keys=[to_user_id], back_populates="received_requests")