Set Cache Control for Entire S3 Bucket

S3 buckets can be used to host static websites and cache control header can be set on S3 objects. However, how can the cache control header be set for the whole bucket or for each files within a bucket.At present, it is not possible to create bucket policy for the bucket that will apply cache control header for all objects, however, it can be achieved from the command line and also from the console.

Apply Cache Control Using AWS Console

To change Cache Control for all objects in a bucket, open the bucket in the console, select all the folders and files and click on More > Change metadata. In the Change Metadata section, set Cache Control as the header and the value as max-age=’value in seconds’.

Apply Cache Control from Command Line

Cache Control metadata can also be changed from the command line. The command line tool can be used to add or modify metadata of objects. However, note that the metadata can only be added or modified by copying the object to itself. Below is a snippet of the command.


    -- single object
    
    aws s3 cp s3://s3-bucket/file.txt s3://s3-bucket/file.txt --metadata-directive REPLACE --cache-control max-age=86400


    --all files in a bucket (use the recursive flag)

    aws s3 cp s3://s3-bucket/ s3://s3-bucket/ --metadata-directive REPLACE --recursive --cache-control max-age=86400


    --only images

    aws s3 cp s3://s3-bucket/ s3://s3-bucket/ --metadata-directive REPLACE 
        --exclude "*" --include "*.jpg" --include "*.gif" \ --include "*.png"
        --recursive --cache-control max-age=86400

Note that the recursive keyword needs to be used to apply the command to all files in the bucket.

Apply Cache Control for Websites served from Cloudfront

Cloudfront can be used as a CDN to serve content from the edge locations. The Cache Control can be set for both browser / proxy and Cloudfront by using max-age and s-max-age directives. When set, the s-max-age directive applies caching time for object in the browser or proxy and the max-age directive applies caching time in Cloudfront.


        -- single object
        
        aws s3 cp s3://s3-bucket/file.txt s3://s3-bucket/file.txt --metadata-directive REPLACE --cache-control max-age=86400,s-maxage=86400
    
    
        --all files in a bucket (use the recursive flag)
    
        aws s3 cp s3://s3-bucket/ s3://s3-bucket/ --metadata-directive REPLACE --recursive --cache-control max-age=86400,s-maxage=86400
    
    
        --only images
    
        aws s3 cp s3://s3-bucket/ s3://s3-bucket/ --metadata-directive REPLACE 
            --exclude "*" --include "*.jpg" --include "*.gif" \ --include "*.png"
            --recursive --cache-control max-age=86400,s-maxage=86400