在浏览器上禁用缓存而不在清漆上禁用它

Question

我在 centos 7 上有一个 varnish 运行。我的网站适用于 Drupal。 Varnish 工作完美，但浏览器也会缓存内容，这会影响用户看到的内容。

向站点添加帖子时，varnish 会重置缓存，但浏览器缓存会显示旧的缓存数据。

如何在浏览器上禁用缓存而不影响清漆。

我的default.vcl:

# This is a basic VCL configuration file for varnish.  See the vcl(7)
# man page for details on VCL syntax and semantics.
# 
# Default backend definition.  Set this to point to your content
# server.
# 
backend default {
  .host = "mysite.com";
  .port = "6060";
  .connect_timeout = 3600s;
  .first_byte_timeout = 3600s;
  .between_bytes_timeout = 3600s;
}

# 
# Below is a commented-out copy of the default VCL logic.  If you
# redefine any of these subroutines, the built-in logic will be
# appended to your code.
# 
 sub vcl_recv {
 
   # Add a unique header containing the client address
  remove req.http.X-Forwarded-For;
  set    req.http.X-Forwarded-For = client.ip;
 
   # set the custom header
   if (req.http.Cookie ~ "ABtesting=B") {
  set req.http.X-ABtesting = "B";
   } else {
  set req.http.X-ABtesting = "A";
   }
 
 # do this only once per request
 if (req.restarts == 0) {
   # normalize Accept-Encoding to reduce vary
   if (req.http.Accept-Encoding) {
  if (req.http.User-Agent ~ "MSIE 6") {
    unset req.http.Accept-Encoding;
  } elsif (req.http.Accept-Encoding ~ "gzip") {
    set req.http.Accept-Encoding = "gzip";
  } elsif (req.http.Accept-Encoding ~ "deflate") {
    set req.http.Accept-Encoding = "deflate";
  } else {
    unset req.http.Accept-Encoding;
  }
   }
 }
 
 if (req.http.User-Agent ~ "(Mobile|Android|iPhone|iPad)") {
   set req.http.User-Agent = "mobile";
 } else {
   set req.http.User-Agent = "desktop";
 }
 
 
     if (req.request != "GET" &&
       req.request != "HEAD" &&
       req.request != "PUT" &&
       req.request != "POST" &&
       req.request != "TRACE" &&
       req.request != "OPTIONS" &&
       req.request != "DELETE") {
         /* Non-RFC2616 or CONNECT which is weird. */
         return (pipe);
     }
     if (req.request != "GET" && req.request != "HEAD") {
         /* We only deal with GET and HEAD by default */
         return (pass);
     }
 // Remove has_js and Google Analytics __* cookies.
 set req.http.Cookie = regsuball(req.http.Cookie, "(^|;\s*)(_[_a-z]+|has_js)=[^;]*", "");
 // Remove a ";" prefix, if present.
 set req.http.Cookie = regsub(req.http.Cookie, "^;\s*", "");
     if (req.http.Authorization /*|| req.http.Cookie*/) {
         /* Not cacheable by default */
         return (pass);
     }
     return (lookup);
 }

# 
# sub vcl_pipe {
#     # Note that only the first request to the backend will have
#     # X-Forwarded-For set.  If you use X-Forwarded-For and want to
#     # have it set for all requests, make sure to have:
#     # set bereq.http.connection = "close";
#     # here.  It is not set by default as it might break some broken web
#     # applications, like IIS with NTLM authentication.
#     return (pipe);
# }
# 
# sub vcl_pass {
#     return (pass);
# }
# 
# sub vcl_hash {
#     set req.hash += req.url;
#     if (req.http.host) {
#         set req.hash += req.http.host;
#     } else {
#         set req.hash += server.ip;
#     }
#     return (hash);
# }
# 
# sub vcl_hit {
#     if (!obj.cacheable) {
#         return (pass);
#     }
#     return (deliver);
# }
# 
# sub vcl_miss {
#     return (fetch);
# }
# 
 sub vcl_fetch {
 
    # vary on the custom header
   if (beresp.http.Vary) {
  set beresp.http.Vary = beresp.http.Vary ", X-ABtesting";
   } else {
  set beresp.http.Vary = "X-ABtesting";
   }
     if (!beresp.cacheable) {
         return (pass);
     }
     if (beresp.http.Set-Cookie) {
         return (pass);
     }
     return (deliver);
 }
 
 sub vcl_deliver {
 if (resp.http.Vary) {
    set resp.http.Vary = regsub(resp.http.Vary, "X-ABtesting", "Cookie");
 }
 
     return (deliver);
 }
# 
# sub vcl_error {
#     set obj.http.Content-Type = "text/html; charset=utf-8";
#     synthetic {"
# <?xml version="1.0" encoding="utf-8"?>
# <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
#  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
# <html>
#   <head>
#     <title>"} obj.status " " obj.response {"</title>
#   </head>
#   <body>
#     <h1>Error "} obj.status " " obj.response {"</h1>
#     <p>"} obj.response {"</p>
#     <h3>Guru Meditation:</h3>
#     <p>XID: "} req.xid {"</p>
#     <hr>
#     <p>Varnish cache server</p>
#   </body>
# </html>
# "};
#     return (deliver);
# }

Answer 1

要在浏览器端控制缓存，您必须使用 Cache-Control 响应 header。参见 here。您应该在您的 Drupal 代码中控制这个 header。

Answer 2

您要查找的是浏览器缓存和 Varnish 缓存的不同 TTL。

如 here 所述，最简单的解决方案是在 Cache-Control 中使用 s-maxage 指令，例如：

Cache-Control: s-maxage=31536000, max-age=300

其中 31536000 是 Varnish 缓存的秒数，300 是您希望资源缓存的秒数缓存在浏览器中。

之所以可行，是因为 s-maxage 覆盖了共享缓存（Varnish 是）的过期时间，而不适用于私有缓存（浏览器是）。

我认为这是最优雅的解决方案，但需要您调整后端应用程序。

this post 中概述了另一个解决方案，只需调整您的 VCL 即可完成：

    sub vcl_fetch {

            if (beresp.ttl > 0s) {
                    /* Remove Expires from backend, it's not long enough */
                    unset beresp.http.expires;

                    /* Set the clients TTL on this object */
                    set beresp.http.cache-control = "max-age=900";

                    /* Set how long Varnish will keep it */
                    set beresp.ttl = 1w;

                    /* marker for vcl_deliver to reset Age: */
                    set beresp.http.magicmarker = "1";
            }
    }

    sub vcl_deliver {
            if (resp.http.magicmarker) {
                    /* Remove the magic marker */
                    unset resp.http.magicmarker;

                    /* By definition we have a fresh object */
                    set resp.http.age = "0";
            }
    }

在浏览器上禁用缓存而不在清漆上禁用它

Disable cache on browser without disabling it on varnish

browser

drupal

varnish

drupal-cache