Amazon Lambda add expires headers to S3 storage uploads automatically

Handy if you are using cloudfront, which is unable (sadly) to add extra headers based on S3 source files.

Runtime
Node.js 4.3

Handler
index.handler

Rest is up to you

Memory
128MB

Timeout
5 sec

VPC
No

Triggers
No -> I have set this up in the bucket config -> Events -> add notification for “Object created”

Code
[code:1:8244eb22f3]’use strict’;

// CONFIGURATION //////////////////////////////////////////////
var CacheControlHeader = ‘public, max-age=31536000’;
var lineBreak = ‘nn—————————————–nn’;
///////////////////////////////////////////////////////////////

console.log(’Loading function…’);

let aws = require(’aws-sdk’);
let s3 = new aws.S3({ apiVersion: ‘2006-03-01′ });

exports.handler = (event, context, callback) => {
const bucket = event.Records[0].s3.bucket.name;
const key = decodeURIComponent(event.Records[0].s3.object.key.replace(/+/g, ” “));
var params = { Bucket: bucket, Key: key };
s3.getObject(params, (err, data) => {
if (err) {
console.log(err);
var message = lineBreak+’Error encountered!nnFailed to get object: s3://’+bucket+’/’+key +’.nnMake sure it is in the same region as this function!’+lineBreak;
console.log(message);
} else {
const mimeHeader = data.ContentType;
if (data.CacheControl != CacheControlHeader) {
var params = { Bucket: bucket, Key: key, CopySource: encodeURIComponent(bucket+’/’+key), ContentType: data.ContentType, CacheControl: CacheControlHeader, ‘Metadata’:{}, MetadataDirective: ‘REPLACE’ };
s3.copyObject(params, (err, data) => {
if (err) {
console.log(err);
message = lineBreak+’Error encountered!nnFailed to get object: s3://’+bucket+’/’+key +’.nnMake sure it is in the same region as this function!’+lineBreak;
console.log(message);
} else {
message = lineBreak+’Metadata updated successfully!nnOBJECT: s3://’+bucket+’/’+key+’nCONTENT-TYPE: ‘+mimeHeader+’nCACHE-CONTROL: ‘+CacheControlHeader+”+lineBreak;
console.log(message);
}
});
} else {
message = lineBreak+’Metadata already updated!nnOBJECT: s3://’+bucket+’/’+key+’nCONTENT-TYPE: ‘+mimeHeader+’nCACHE-CONTROL: ‘+CacheControlHeader+”+lineBreak;
console.log(message);
}

}
});
};[/code:1:8244eb22f3]