Pfthb

I tried to checked already existing questions and answers but couldn't find answer to my topic. Things i checked:

• i have proper certificate on my domain


• i am sending proper response headers(at least i think so, blured thing is location header with s3 url):

More information:

• we use http2.0 from cloudflare, can it affect this anyhow?


• on our server we use just nginx+php-fpm

What's exactly a scenario - We generate minified images using parameters from post request on our server and save it on S3. I wanted to cache those requests with Last-Modified so browser don't make unnecessary requests, so it looks like currently like this:

1. Request our server with proper parameters(like image size etc), build some kind of object key for saving into s3


2. Resize it, upload resized image to S3.


3. Return image

On next requests:

1. Request our server, build key again


2. Check if it exists on S3, if yes, return just redirect to s3 url.


3. If not then do resize and upload again and return image

I wanted to change this to:

1. Request our server with proper parameters(like image size etc), build some kind of key for saving


2. Resize it, upload resized image to S3 if needed


3. Return image or redirect to s3 with last-modified header.

On next requests:

1. Check if-modified-since header


2. If the difference with current date is less than 72h(max s3 url ttl) and image wasn't updated(we have updated date on database) then return 304.


3. If not then do what's above.

What is even more random, sometimes like 1 per 10 or 20 requests it's working correctly, like i have 304 request sometimes, but it's really rare case.

Any idea?