Signature Does not match error on presignedUrl DigitalOCeane - amazon-web-services

Question

I am using DigitalOcean for storing videos. I am using Firebase callable function to generate the signed URL with AWS SDK and sent it back to my app. When I use Firebase function to generate a signed URL then it gives me the Signature Does not match error. The Firebase function is as follows-
const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp();
const AWS = require('aws-sdk');
exports.getS3SignedUrlUpload = functions.https.onCall((data, context) => {
const spacesEndpoint = new AWS.Endpoint('https://sgp1.digitaloceanspaces.com');
AWS.config.update({
endpoint: spacesEndpoint,
accessKeyId: 'mykey',
secretAccessKey: 'mySecretKey',
signatureVersion: 'v4',
region: "sgp1"
});
var s3 = new AWS.S3();
const s3Params = {
Bucket: 'myappvideo', //data.S3BucketName,
Key: 'video14.mp4',//data.key,
Expires: 60*60 // Expires in 10 minutes
};
var v = s3.getSignedUrl('putObject', s3Params);
console.log("PRESIGNED URL", v);
return v;
});

Answer 1

I accidentally use getObject instead of putObject. Now it is working fine for me. But I don't know why it works, as I don't have any networking concepts. The line where I did the change is:
var v = s3.getSignedUrl('putObject', s3Params);
to
var v = s3.getSignedUrl('getObject', s3Params);