title: How to use pre-signed urls with multiple files in s3 using angular
body: <p>I have a list called students.Assume it contains 100 items.So every students pro picture is stored in s3 bucket with the student id as it's file name.</p>
  
  <p>My question is how to access all these images with presigned urls.</p>
  
  <p>If I generate url when getting data, I think it's a bad practice,because it's getting some time to finish in server side.
  I can't store it.It will expire and I saw in many articles saying it's a bad practice. 
  How to do this.Is there a way to do this in client side?.I'm using Angular 8 in client side.</p>
  
  <p>Here is the code I use to generate pre-signed url.This code is working fine.But the problem is after the url expire, again needs to generate it.</p>
  
  <pre><code>const AWS = require('aws-sdk');
  const s3 = new AWS.S3();
  const s3BucketName = 'media';
  exports.handler = async (event) =&gt; {
      try{
    const objectKey = '1234.jpg';
    let params = {
          Bucket: s3BucketName,
          Key: objectKey,
          Expires: 60 * 60 * 24 * 365 * 10
       };
      return await s3.getSignedUrlPromise('getObject', params).then(async url =&gt; {
           console.log('Successfully generated pre signed image url:', url);
  
  
  
          const payload = {
              message: 'success',
              imageUrl: url
          };
          const response = {
              statusCode: 201,
               body: JSON.stringify(payload),
          };
          return response;
      }).catch(error =&gt; {
          console.error(`Failed to generate presigned url: ${error}`);
          return {
              statusCode: error.statusCode || 501,
              body: JSON.stringify({
                  message: `Failed to generate presigned url. Request Id: ${context.awsRequestId}`
              })
          };
      });
  
      }catch(error){
          console.log(JSON.stringify(error));
         const response = {
          statusCode: 501,
          body: JSON.stringify(error),
      };
      return response;  
      }
  
  };
  </code></pre>
  
  <p>please help me. thanks</p>