How to determine if object exists AWS S3 Node.JS sdk

Question

I need to check if a file exists using AWS SDK. Here is what I'm doing:

var params = {
    Bucket: config.get('s3bucket'),
    Key: path
};

s3.getSignedUrl('getObject', params, callback);

It works but the problem is that when the object doesn't exists, the callback (with arguments err and url) returns no error, and when I try to access the URL, it says "NoSuchObject".

Shouldn't this getSignedUrl method return an error object when the object doesn't exists? How do I determine if the object exists? Do I really need to make a call on the returned URL?

Answer 1

Before creating the signed URL, you need to check if the file exists directly from the bucket. One way to do that is by requesting the HEAD metadata.

// Using callbacks s3.headObject(params, function (err, metadata) {     if (err && err.name === 'NotFound') {       // Handle no object on cloud here     } else if (err) {     // Handle other errors here....   } else {       s3.getSignedUrl('getObject', params, callback);       // Do stuff with signedUrl   } });  // Using async/await try {   await s3.headObject(params).promise();   const signedUrl = s3.getSignedUrl('getObject', params);   // Do stuff with signedUrl } catch (error) {   if (error.name === 'NotFound') {     // Handle no object on cloud here...   } else {     // Handle other errors here....   } } 

Answer 2

The simplest solution without try/catch block.

const exists = await s3
  .headObject({
    Bucket: S3_BUCKET_NAME,
    Key: s3Key,
  })
  .promise()
  .then(
    () => true,
    err => {
      if (err.code === 'NotFound') {
        return false;
      }
      throw err;
    }
  );