How to change content type of Amazon S3 Objects

Question

The objects in my Amazon S3 bucket are all of the content type application/octet-stream. Some of these objects are PDFs, sometimes images like JPG,

Answer 1

You can use AWS sdk (php or other) I'll show how it works using CLI. To change content type on S3 given object, you need to copy this object and update the metadata information using the REPLACE tag so it copies to itself, you can achieve that using http://docs.aws.amazon.com/cli/latest/reference/s3api/copy-object.html

aws s3api copy-object --bucket  \
    --content-type "images/jpeg" \
    --copy-source /path/to/images.jpeg \
    --key path/to/images.jpeg \
    --metadata-directive "REPLACE"