Generating Amazon S3 file upload Policy in Node.js


I recently (by recently, I mean two days ago) had to upload files – images to be precise – to a newly created Amazon S3 bucket. After going through a few documents online and following instructions (at least, I think I did), I had my environment (MEAN – MongoDb, Express, AngularJS and Node.js) setup for the upload.

On trying the upload, Amazon returned an error telling me the policy I was using was not the same as that which they generated. Apparently, I did something wrong somewhere so I sought to right my wrong. I found a valuable script on github (though for the life of me, I can’t seem to remember the name of the project) and here’s what I distilled it down to:

To use this, I just issue a  GET  request of the form:  http://localhost:3000/s3_policy?subFolder=folder_name&mimeType=image/png