AWS S3 automatic object key name normalization to lower case - amazon-web-services

Question

AFAIK, object names on AWS S3 are always case sensitive and it is impossible to configure AWS S3 to be case insensitive.
So, is it possible to configure something like AWS Lambda in order to normalize uploaded file names to lower case? Or what is the best practice to perform this task with AWS S3?

Answer 1

Yes, this is easily done by having a Lambda function subscribe to your S3 PUT Event.
{
"Records": [
{
"eventVersion": "2.0",
"eventTime": "1970-01-01T00:00:00.000Z",
"requestParameters": {
"sourceIPAddress": "127.0.0.1"
},
"s3": {
"configurationId": "testConfigRule",
"object": {
"eTag": "0123456789abcdef0123456789abcdef",
"sequencer": "0A1B2C3D4E5F678901",
"key": "HappyFace.jpg",
"size": 1024
},
"bucket": {
"arn": bucketarn,
"name": "sourcebucket",
"ownerIdentity": {
"principalId": "EXAMPLE"
}
},
"s3SchemaVersion": "1.0"
},
"responseElements": {
"x-amz-id-2": "EXAMPLE123/5678abcdefghijklambdaisawesome/mnopqrstuvwxyzABCDEFGH",
"x-amz-request-id": "EXAMPLE123456789"
},
"awsRegion": "us-east-1",
"eventName": "ObjectCreated:Put",
"userIdentity": {
"principalId": "EXAMPLE"
},
"eventSource": "aws:s3"
}
]
}
You can then grab event.Records[0].s3.bucket.name and event.Records[0].s3.object.key to make a copyObject request to AWS
Once your file has been copied successfully, you can then delete the original file.
Just make sure your Lambda is configured for PUT events only, because if you set it to ALL events, both COPY and DELETE will also trigger your function, making you enter in an infinite recursion.