PHP session forces varnish not to cache

Question

I am trying to understand the behavior of varnish and was hoping that someone could shed some light.

I am doing a test where I am trying to make a varnish for caching requests / responses using cookies.

I have a very simple PHP script, it just starts the session.

<?php session_start(); ?>

I expect the varnish will not cache from Set-Cookie and Cookie headers .

I will leave and turn off these headers:

sub vcl_backend_response {
    unset beresp.http.set-cookie;
}

sub vcl_recv {
    unset req.http.cookie;
}

The requested page is still not cached .

I know that PHP will send cache headers that can be respected by varnish. Let check:

<?php echo session_cache_limiter(); ?>

Output: nocache

From session_cache_limiter (), the documentation is known for nocache sending these responce headers to overload the cache:

Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Pragma: no-cache

:

sub vcl_backend_response {
    unset beresp.http.expires;
    unset beresp.http.pragma;
    unset beresp.http.cache-control;
    unset beresp.http.set-cookie;
}

, , .

, , - ttl:

sub vcl_backend_response {
    unset beresp.http.expires;
    unset beresp.http.pragma;
    unset beresp.http.cache-control;
    unset beresp.http.set-cookie;

    # THIS MADE VARNISH TO CACHE
    set beresp.ttl = 10m;
}

:

TTL , 2m (-t 120 CLI ), ?

/usr/sbin/varnishd -P /var/run/varnish.pid -f /etc/varnish/default.vcl -a :80 -T 0.0.0.0:6082 -t 120 -u varnish -g varnish -S /etc/varnish/secret -s malloc,512M

- ? , TTL ( )?

Answer 1

, Varnish Expires backend response , vcl_backend_response . , vcl_backend_response, TTL ( , ). , (HIT-FOR-PASS). , Expires ( unset beresp.http.expires;), .

, RFC.

, , VCL. PHP session_cache_limiter() (public, private, nocache), (session_cache_limiter('')) .

PHP, cookie, , , .