first commit

历届学生/front-end-team-11/项目开发/上课项目/nodejs博客/backendv2/src/utils/aliyunOss.ts

@@ -0,0 +1,53 @@
+import crypto from "crypto-js";
+
+export class uploadOssHelper {
+    accessKeyId: string = "";
+    accessKeySecret: string = "";
+    timeout: number;
+    maxSize: number;
+    constructor(options: {
+        accessKeyId: string, 
+        accessKeySecret: string,
+        timeout?: number,
+        maxSize?: number
+    }) {
+        this.accessKeyId = options.accessKeyId;
+        this.accessKeySecret = options.accessKeySecret;
+        // 限制参数的生效时间，单位为小时，默认值为1。
+        this.timeout = options.timeout || 1;
+        // 限制上传文件的大小，单位为MB，默认值为10。
+        this.maxSize = options.maxSize || 10;
+    }
+
+    createUploadParams() {
+        const policy = this.getPolicyBase64();
+        const signature = this.signature(policy);
+        return {
+            OSSAccessKeyId: this.accessKeyId,
+            policy: policy,
+            Signature: signature,
+        };
+    }
+
+    getPolicyBase64() {
+        let date = new Date();
+        // 设置policy过期时间。
+        date.setHours(date.getHours() + this.timeout);
+        let srcT = date.toISOString();
+        const policyText = {
+            expiration: srcT,
+            conditions: [
+                // 限制上传文件大小。
+                ["content-length-range", 0, this.maxSize * 1024 * 1024],
+            ],
+        };
+        const buffer = new Buffer(JSON.stringify(policyText));
+        return buffer.toString("base64");
+    }
+
+    signature(policy: string) {
+        return crypto.enc.Base64.stringify(
+            crypto.HmacSHA1(policy, this.accessKeySecret)
+        );
+    }
+}