如何在我的网站中启用If-Modified-Since HTTP标头

Question

I want to implement If-Modified-Since HTTP header in my site. How do I ensure the If-Modified-Since HTTP header is supported and that it is active?. If it is supported but not active then how to make it active?

Do I have to make any necessary configuration in htaccess or in apache server's.conf file to enable it?

Answer 1

This header is related to your HTTP server configuration. If you are using Apache, see Expires module. You'll have to set some cache configuration for your assets, example

# Turn on cache control
ExpiresActive On
# Enable caching for PNG image (1 week)
ExpiresByType image/png M604800

If you are using another HTTP server, read the doc.