feat: add refreshSTSToken example (#924)

README.md

@@ -378,6 +378,24 @@ const store = new OSS({
 });
 ```
 
+4. use STS and refreshSTSToken
+```js
+const OSS = require('ali-oss');
+
+const store = new OSS({
+  accessKeyId: 'your STS key',
+  accessKeySecret: 'your STS secret',
+  stsToken: 'your STS token',
+  refreshSTSToken: async () => {
+    return {
+      accessKeyId: 'your refreshed STS key',
+      accessKeySecret: 'your refreshed STS secret',
+      stsToken: 'your refreshed STS stoken'
+    }
+  }
+});
+```
+
 ## Bucket Operations
 
 ### .listBuckets(query[, options])

lib/common/client/initOptions.js

@@ -20,27 +20,33 @@ function setEndpoint(endpoint, secure) {
 }
 
 module.exports = function (options) {
-  if (!options
-    || !options.accessKeyId
-    || !options.accessKeySecret) {
+  if (!options || !options.accessKeyId || !options.accessKeySecret) {
     throw new Error('require accessKeyId, accessKeySecret');
   }
+  if (options.stsToken && !options.refreshSTSToken) {
+    console.warn(
+      "It's recommended to set `refreshSTSToken` to refresh stsToken、accessKeyId、accessKeySecret automatically when sts info expires"
+    );
+  }
   if (options.bucket) {
     _checkBucketName(options.bucket);
   }
-  const opts = Object.assign({
-    region: 'oss-cn-hangzhou',
-    internal: false,
-    secure: false,
-    timeout: 60000,
-    bucket: null,
-    endpoint: null,
-    cname: false,
-    isRequestPay: false,
-    sldEnable: false,
-    headerEncoding: 'utf-8',
-    refreshSTSToken: null
-  }, options);
+  const opts = Object.assign(
+    {
+      region: 'oss-cn-hangzhou',
+      internal: false,
+      secure: false,
+      timeout: 60000,
+      bucket: null,
+      endpoint: null,
+      cname: false,
+      isRequestPay: false,
+      sldEnable: false,
+      headerEncoding: 'utf-8',
+      refreshSTSToken: null
+    },
+    options
+  );
 
   opts.accessKeyId = opts.accessKeyId.trim();
   opts.accessKeySecret = opts.accessKeySecret.trim();