How to use OSS SDK for Browser.js to preview and download an object - Object Storage Service

You can use the signatureUrl method in a browser to generate the URL to download or preview an object. You can use the download attribute of the <a> HTML element or the window.open API to obtain the URL of an object.

Usage notes

When you use packaging tools such as Webpack and Browserify, install OSS SDK for Browser.js by running the npm install ali-oss command.
If you want to access an OSS bucket from a browser but no CORS rules are configured for the bucket, the browser rejects the request. Therefore, you must configure CORS rules for a bucket if you want to access the bucket from a browser. For more information, see Installation.
In most cases, OSS SDK for Browser.js is used in browsers. To prevent your AccessKey pair from being exposed, we recommend that you use temporary access credentials obtained from Security Token Service (STS) to access OSS.
The temporary access credentials consist of an AccessKey pair and a security token. The AccessKey pair consists of an AccessKey ID and an AccessKey secret. For more information about how to obtain temporary access credentials, see Use STS for temporary access authorization.

Obtain the URL of an object for previews

The following code provides an example on how to obtain the URL of an object named exampleobject.txt in a bucket named examplebucket for previews.

Note

To preview an object in a browser, set Content-Disposition to inline and use the custom domain name that is mapped to the bucket to access the object. For more information, see Configure object metadata and Use custom domain names.

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <title>Document</title>
  </head>

  <body>
    <!-- Import the SDK file -->
    <script
      type="text/javascript"
      src="https://gosspublic.alicdn.com/aliyun-oss-sdk-6.18.0.min.js"
    ></script>
    <script type="text/javascript">
      const client = new OSS({
        // Specify the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the region to oss-cn-hangzhou. 
        region: "yourRegion",
        authorizationV4: true,
        // Specify the temporary AccessKey pair obtained from STS. 
        accessKeyId: "yourAccessKeyId",
        accessKeySecret: "yourAccessKeySecret",
        // Specify the security token obtained from STS. 
        stsToken: "yoursecurityToken",
        // Specify the name of the bucket. 
        bucket: "examplebucket",
      });
      
      // Specify the full path of the object. Do not include the bucket name in the full path. 
      const url = client.signatureUrl("example.jpg", {
        // If you want to add an image style to the generated signed URL, you can use the process parameter to specify the style in the "style/image style name" format. 
        // process: "style/imagestyle",
      });
      console.log(url);

      // Specify the validity period of a signed URL. Unit: seconds. If you do not specify the validity period, the signed URL is valid for 1800 seconds. 
      // url = client.signatureUrl('example.jpg', {expires: 3600});
      // console.log(url);
    </script>
  </body>
</html>

Obtain the URL to download an object

The following code provides an example on how to obtain the URL to download an object named exampleobject.txt in a bucket named examplebucket. By default, the validity period of the URL is 1,800 seconds.

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <title>Document</title>
  </head>

  <body>
    <!-- Import the SDK file -->
    <script
      type="text/javascript"
      src="https://gosspublic.alicdn.com/aliyun-oss-sdk-6.18.0.min.js"
    ></script>
    <script type="text/javascript">
      const client = new OSS({
        // Specify the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the region to oss-cn-hangzhou. 
        region: "yourRegion",
        authorizationV4: true,
        // Specify the temporary AccessKey pair obtained from STS. The AccessKey pair consists of an AccessKey ID and an AccessKey secret. 
        accessKeyId: "yourAccessKeyId",
        accessKeySecret: "yourAccessKeySecret",
        // Specify the security token obtained from STS. 
        stsToken: "yoursecurityToken",
        // Specify the name of the bucket. 
        bucket: "examplebucket",
      });

      // Set the response header to automatically download an object by using the URL, and set the name of the local file after the object is downloaded. 
      const filename = "examplefile.txt";
      const response = {
        "content-disposition": `attachment; filename=${encodeURIComponent(
          filename
        )}`,
      };
      // Specify the full path of the object. Do not include the bucket name in the full path. 
      const url = client.signatureUrl("exampleobject.txt", { response });
      console.log(url);
    </script>
  </body>
</html>