Custom headers on Amazon S3

Question

Is it possible to have custom headers on Amazon S3 with arbitrary naming?

For example, I am using a CDN pointing to Amazon S3 as the origin server, and in order to enable advanced functionality on the CDN I need to use a custom header x-something-something...

I see it's possible to do this with x-amz-meta-(something) but what about something more general like x-(something)-(something) without the amz?

Dissimulate

What can you not accomplish with the headers prefixed in that way? – Muskogee

Answer 1

I don't think it is possible with their current API. They cover the major headers you will need for caching and browser interoperability.

I think they are being safe in only allowing x-amz-meta- prefixed custom headers, possibly to keep from clashing with user selected headers when they update their api in the future.

If you need custom attributes attached to your objects, it should be trivial to parse out the x-amz-meta- in your client application.

Muskogee

"Trivial" if you control the client application... but if it is some third party, it's not so trivial! – Dissimulate

@Dissimulate I suppose if you don't access AWS directly you are beholden to the limitations of whatever you are using. – Muskogee

Thanks, I was wondering why I couldn't set custom headers on my own. The x-amz-meta-prefix did it indeed (a fact poorly documented by Amazon). – Edda

I am using their static website hosting solution and i want to set X-Frame-Options. But now i can't, I need to think of some other solution – Leonardo

Answer 2

This beautiful article explains it all: Serving custom headers from static sites on CloudFront/S3 with Lambda@Edge

tldr:

You can't—do it only with S3. You need to use CloudFront and Lambda via Lambda@Edge. It's an integration between Lambda and CloudFront. It allows you to run Lambdas within the CloudFront. This allows you to change headers among other things. So if you are ok accessing your S3 via CloudFront then this could be a viable option.

Leonardo

See also #63204119 – Evert

Now we can do this using reponse header policy see https://mcmap.net/q/500650/-how-to-add-headers-to-cloudfront-response – Supposititious

Answer 3

Amazon now natively supports adding security headers.

Blog with information: Amazon CloudFront introduces Response Headers Policies

Documentation: create-response-headers-policy

Leonardo

Answer 4

I was able to achieve this using the s3cmd tool. I wrote a sync script that syncs my static site using the --cache-control parameter on the AWS client tool and then manually resets it and adds a couple of other headers for a few specific files:

cd /appropriatedirectory

# Delete current site
aws s3 rm s3://yourbucket --recursive --exclude 'logs/*'

# Upload new site, setting cache header to 1 month for all files
aws s3 sync . s3://yourbucket --exclude '.idea/\*' --exclude '.git/\*' --exclude '.gitignore' --cache-control max-age=2592000

# Overrides the cache headers for some file
python /pathToS3cmd/s3cmd  modify --add-header="Cache-Control:no-cache,no-store,must-revalidate" s3://yourbucket/somefile.html
python /pathToS3cmd/s3cmd/s3cmd  modify --add-header="Expires:0" s3://yourbucket/somefile.html
python /pathToS3cmd/s3cmd/s3cmd  modify --add-header="Pragma:no-cache" s3://yourbucket/somefile.html

Poco

This has some cruft in it for ignoring logs, IntelliJ, and Git files. I left it in as a hopefully helpful example of a practical sync script. – Poco

Unfortunately, only a restricted set of headers is supported. Standard cache control related headers are supported though. docs.aws.amazon.com/AmazonS3/latest/API/… – Electromotor