feat: 增加 rsaCheck 验签方法 (#142)

closes #140

README.md

@@ -362,6 +362,34 @@ const success = sdk.checkNotifySignV2(postData);
 const plainText = alipaySdk.aesDecrypt(getPhoneNumberResponse);
 ```
 
+### 对前端返回的报文进行验签
+
+参考 https://opendocs.alipay.com/common/02mse3#AES%20%E8%A7%A3%E5%AF%86%E5%87%BD%E6%95%B0 的算法
+
+前端返回的内容
+
+```json
+{
+ "response": "hvDOnibG0DPcOFPNubK3DEfLQGL4=",
+ "sign": "OIwk7zfZMp5GX78Ow==",
+ "sign_type": "RSA2",
+ "encrypt_type": "AES",
+ "charset": "UTF-8"
+}
+```
+
+通过 alipay-sdk 验签
+
+```ts
+// 注意，加密内容必须前后加上双引号
+const signContent = '"hvDOnibG0DPcOFPNubK3DEfLQGL4="';
+const sign = 'OIwk7zfZMp5GX78Ow==';
+const signType = 'RSA2';
+const signCheckPass = alipaySdk.rsaCheck(signContent, sign, signType);
+
+console.log(signCheckPass);
+```
+
 ## alipay-sdk v3 到 v4 的升级说明
 
 从 v3 到 v4 有以下不兼容变更，请参考示例代码进行更新

src/alipay.ts

@@ -9,7 +9,7 @@ import camelcaseKeys from 'camelcase-keys';
 import snakeCaseKeys from 'snakecase-keys';
 import { Stream as SSEStream } from 'sse-decoder';
 import { AlipayFormStream } from './AlipayFormStream.js';
-import type { AlipaySdkConfig } from './types.js';
+import type { AlipaySdkConfig, AlipaySdkSignType } from './types.js';
 import { AlipayFormData } from './form.js';
 import {
   sign, ALIPAY_ALGORITHM_MAPPING, decamelize, createRequestId, readableToBytes,
@@ -732,7 +732,7 @@ export class AlipaySdk {
   }
 
   // 消息验签
-  private notifyRSACheck(signArgs: { [key: string]: any }, signStr: string, signType: 'RSA' | 'RSA2', raw?: boolean) {
+  private notifyRSACheck(signArgs: { [key: string]: any }, signStr: string, signType: AlipaySdkSignType, raw?: boolean) {
     const signContent = Object.keys(signArgs).sort().filter(val => val)
       .map(key => {
         let value = signArgs[key];
@@ -748,10 +748,7 @@ export class AlipaySdk {
         return `${key}=${decodeURIComponent(value)}`;
       })
       .join('&');
-
-    const verifier = createVerify(ALIPAY_ALGORITHM_MAPPING[signType]);
-
-    return verifier.update(signContent, 'utf8').verify(this.config.alipayPublicKey, signStr, 'base64');
+    return this.rsaCheck(signContent, signStr, signType);
   }
 
   /**
@@ -1024,4 +1021,14 @@ export class AlipaySdk {
   aesDecrypt(encryptedText: string) {
     return aesDecryptText(encryptedText, this.config.encryptKey);
   }
+
+  /**
+   * 对指定内容进行验签
+   *
+   * 如对前端返回的报文进行验签 https://opendocs.alipay.com/common/02mse3#AES%20%E8%A7%A3%E5%AF%86%E5%87%BD%E6%95%B0
+   */
+  rsaCheck(signContent: string, sign: string, signType: AlipaySdkSignType = 'RSA2') {
+    const verifier = createVerify(ALIPAY_ALGORITHM_MAPPING[signType]);
+    return verifier.update(signContent, 'utf-8').verify(this.config.alipayPublicKey, sign, 'base64');
+  }
 }

src/types.ts

@@ -1,3 +1,5 @@
+export type AlipaySdkSignType = 'RSA2' | 'RSA';
+
 /**
  * @interface AlipaySdkConfig SDK 配置
  */
@@ -7,7 +9,7 @@ export interface AlipaySdkConfig {
   /** 应用私钥字符串。RSA签名验签工具：https://docs.open.alipay.com/291/106097）*/
   privateKey: string;
   /** 签名种类，默认是 RSA2 */
-  signType?: 'RSA2' | 'RSA';
+  signType?: AlipaySdkSignType;
   /** 支付宝公钥（需要对返回值做验签时候必填） */
   alipayPublicKey?: string;
   /** 网关 */