完成第12讲作业：痕迹抹除（删除用户和删除文件）

backend/src/file.ts

@@ -74,4 +74,47 @@ router.get("/download", authenticate, (req, res) => {
   }
 });
 
+// 删除文件接口
+router.delete("/delete/:room/:filename", authenticate, (req, res) => {
+  // 获取路径参数
+  const { room, filename } = req.params;
+
+  // 校验参数
+  if (!room || !filename) {
+    return res.status(422).send("422 Unprocessable Entity: Missing room or filename");
+  }
+
+  // 路径安全过滤
+  const safeRoom = path.normalize(room).replace(/^(\.\.[\/\\])+/, '');
+  const safeFilename = path.normalize(filename).replace(/^(\.\.[\/\\])+/, '');
+
+  if (safeRoom !== room || safeFilename !== filename) {
+    return res.status(403).send("403 Forbidden: Invalid file path");
+  }
+
+  // 拼接文件在服务器上的真实路径
+  const filePath = path.resolve(baseDir, safeRoom, safeFilename);
+
+  // 检查文件是否存在并删除
+  try {
+    if (!fs.existsSync(filePath)) {
+      return res.status(404).send("404 Not Found: File does not exist");
+    }
+
+    // fs.unlinkSync：同步删除文件
+    fs.unlinkSync(filePath);
+
+    // 返回删除成功消息
+    return res.status(200).json({
+      message: "File deleted successfully",
+      deletedFile: `${room}/${filename}`,
+    });
+
+  } catch (err) {
+    // 如果文件被占用、权限不足等，会进到这里
+    console.error(err);
+    return res.status(500).send("500 Internal Server Error");
+  }
+});
+
 export default router;

backend/src/index.ts

@@ -27,6 +27,8 @@ const client = new GraphQLClient(
 );
 export const sdk = getSdk(client);
 
+export const graphqlClient = client;
+
 // Log all requests to the console, optional.
 app.use(morgan(process.env.NODE_ENV === "production" ? "combined" : "dev"));
 

backend/src/user.ts

@@ -1,6 +1,7 @@
 import express from "express";
 import jwt from "jsonwebtoken";
 import { sdk as graphql } from "./index";
+import { graphqlClient } from "./index";
 
 interface userJWTPayload {
   uuid: string;
@@ -71,4 +72,56 @@ router.post("/register", async (req, res) => {
   }
 });
 
+// 删除用户接口 (痕迹抹除)
+
+router.post("/delete", async (req, res) => {
+  // 获取参数并校验
+  const { uuid } = req.body;
+
+  if (!uuid) {
+    return res.status(422).send("422 Unprocessable Entity: Missing user uuid");
+  }
+
+  // 执行 GraphQL 删除操作
+  try {
+    const mutation = `
+      mutation deleteUser($uuid: uuid!) {
+        delete_user(where: {uuid: {_eq: $uuid}}) {
+          affected_rows
+          returning {
+            uuid
+            username
+          }
+        }
+      }
+    `;
+
+    // 调用 graphqlClient.request 发送请求
+    const result = await graphqlClient.request<{
+      delete_user: {
+        affected_rows: number;
+        returning: { uuid: string; username: string }[];
+      };
+    }>(mutation, { uuid });
+
+    // 处理结果
+    // affected_rows 表示数据库中被影响（删除）的行数
+    if (result.delete_user.affected_rows === 0) {
+      // 如果删除了 0 行，说明 uuid 不存在
+      return res.status(404).send("404 Not Found: User does not exist");
+    }
+
+    // 删除成功，返回被删除的用户信息
+    const deletedUser = result.delete_user.returning[0];
+    return res.status(200).json({
+      message: "User deleted successfully",
+      deletedUser: deletedUser,
+    });
+
+  } catch (err) {
+    // 异常捕获
+    console.error(err);
+    return res.status(500).send("500 Internal Server Error");
+  }
+});
 export default router;