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.getSignedU         


        

Answer 1

Use getObject method like this:

var params = {
    Bucket: config.get('s3bucket'),
    Key: path
};
s3.getObject(params, function(err, data){
    if(err) {
        console.log(err);
    }else {
      var signedURL = s3.getSignedUrl('getObject', params, callback);
      console.log(signedURL);
   }
});

Answer 2

by using headObject method

AWS.config.update({
        accessKeyId: "*****",
        secretAccessKey: "****",
        region: region,
        version: "****"
    });
const s3 = new AWS.S3();

const params = {
        Bucket: s3BucketName,
        Key: "filename" //if any sub folder-> path/of/the/folder.ext
}
try {
        await s3.headObject(params).promise()
        console.log("File Found in S3")
    } catch (err) {
        console.log("File not Found ERROR : " + err.code)
}

As params are constant, the best way to use it with const. If the file is not found in the s3 it throws the error NotFound : null.

If you want to apply any operations in the bucket, you have to change the permissions of CORS Configuration in the respective bucket in the AWS. For changing permissions Bucket->permission->CORS Configuration and Add this code.

<CORSConfiguration>
<CORSRule>
    <AllowedOrigin>*</AllowedOrigin>
    <AllowedMethod>PUT</AllowedMethod>
    <AllowedMethod>POST</AllowedMethod>
    <AllowedMethod>DELETE</AllowedMethod>
    <AllowedMethod>GET</AllowedMethod>
    <AllowedMethod>HEAD</AllowedMethod>
    <AllowedHeader>*</AllowedHeader>
</CORSRule>
</CORSConfiguration>

for more information about CORS Configuration : https://docs.aws.amazon.com/AmazonS3/latest/dev/cors.html