John Davidson

Message:

Hello I am working on chat application and I have user profile images these are refreshing after 1s interval using Js.
After 1s my Js script send request to server and on server side it check if user have profile image in database then it send all users profile images.
This make user profile images blinking after 1s.
I want to cache user profile images so that it can't load images from server again and again. First time it load from server and cache images in browser and then for each request it get images from cache not from server.
But when user update their profile image then it must load updated profile image from server.

Please tell if it's possible..
Thanks in advance..

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My Answer:
Yes, it is possible to cache images in the browser using PHP. You can set the appropriate headers in your PHP script to instruct the browser to cache the images. Here is an example of how you can do this:

php
// Set the cache control headers
header("Cache-Control: max-age=3600"); // Cache images for 1 hour

// Check if the image has been modified
if(isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) && strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE']) >= filemtime($imagePath)) {
header("HTTP/1.1 304 Not Modified");
exit;
}

// Set the last modified header
header("Last-Modified: " . gmdate("D, d M Y H:i:s", filemtime($imagePath)) . " GMT");

// Output the image
header("Content-Type: image/jpeg");
readfile($imagePath);


In this example, we are setting the cache control headers to cache the images for 1 hour. We are also checking if the image has been modified since the last request and sending a 304 Not Modified response if it hasn't. This will help reduce the number of requests to the server for the same image.

Remember to replace `$imagePath` with the actual path to your image file.