feat: 优化项目目录结构

apps/backend/src/oss/oss.service.ts

@@ -0,0 +1,53 @@
+import { Injectable } from '@nestjs/common';
+import { STS } from 'ali-oss';
+
+@Injectable()
+export class OssService {
+  private sts = new STS({
+    accessKeyId: process.env.ALIYUN_ACCESS_KEY_ID,
+    accessKeySecret: process.env.ALIYUN_ACCESS_KEY_SECRET,
+  });
+
+  private stsCache: {
+    [session: string]: {
+      credentials: {
+        AccessKeyId: string;
+        AccessKeySecret: string;
+        SecurityToken: string;
+        Expiration: string;
+      };
+      expireTime: number; // 时间戳，单位为毫秒
+    };
+  } = {};
+
+  /** @todo 该方法存在缓存穿透问题，待优化 */
+  async getStsToken(session: string) {
+    if (this.stsCache[session]) {
+      const cached = this.stsCache[session];
+      // 检查缓存是否过期
+      if (cached.expireTime > Date.now()) {
+        return cached.credentials;
+      } else {
+        // 如果过期，删除缓存
+        delete this.stsCache[session];
+      }
+    }
+
+    return this.sts
+      .assumeRole(process.env.ALIYUN_OSS_STS_ROLE_ARN, ``, 3600, `${session}`)
+      .then((res) => {
+        // 缓存
+        this.stsCache[session] = {
+          credentials: res.credentials,
+          expireTime:
+            new Date(res.credentials.Expiration).getTime() - 5 * 60 * 1000, // 提前5分钟过期,
+        };
+
+        return res.credentials;
+      })
+      .catch((err) => {
+        console.error('获取STS Token失败:', err);
+        throw new Error('获取STS Token失败');
+      });
+  }
+}