0

Here's the curl -I response to my Javascript file: 

 HTTP/1.1 200 OK Content-Type: text/javascript Content-Length: 72640 Connection: keep-alive Date: Sat, 18 Feb 2017 16:12:06 GMT Cache-Control: 86400 Last-Modified: Wed, 15 Feb 2017 15:09:28 GMT ETag: "a6ee06ff5e49a4290bb2aabe5e0f9029" Server: AmazonS3 Vary: Accept-Encoding Age: 1173 X-Cache: Hit from cloudfront Via: 1.1 3b17302562f1709d8b6c9f7be1.cloudfront.net (CloudFront)

I can see the Cache-Control tag there. Not sure what the Vary and the ETag are doing, but so be it. Does this somehow specify to a user's browser NOT to cache this file? Why are Pingdom or Goog PageSpeed not recognising this as a browser-cacheable file?

Improve this question

1 Answer 1

Reset to default
2

Your Cache-Control header is present, but the value is not actually valid. The correct format looks like this:

Cache-Control: max-age=86400

The number, by itself, is meaningless.

ETag: is the entity tag -- an opaque value that uniquely identifies the current content of a given URL. If the content changes, the ETag will also change. A browser with a cached copy may use this value for subsequent requests to ask that the server only return the content if it differs, by sending an If-None-Match: request header, including the last-seen ETag.

Vary: tells the browser that certain changes to the request may generate a different response. Unlike browsers, curl doesn't advertise its ability to support gzipped payload unless you specify the --compressed option. Adding that option when invoking curl triggers the addition of Accept-Encoding: gzip to the request, which may trigger the response to be compressed if you have that option enabled in CloudFront.

Improve this answer
Sign up to request clarification or add additional context in comments.

2 Comments

That was it. My Ray Charles moment. Thank you!
Also +1 for the very lucid explanation of Etag and Vary.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.