[SOLVED] Nginx FastCGI caching

What are you trying to accomplish with all that stuff? Caching only for non-logged-in users? Separate cache for each logged-in user?

What version of nginx are you using? The newest versions have new options that might make much of that stuff unnecessary. Would you consider upgrading to the latest?

That capture ($1) in the set directives looks like it'd add a great deal of junk.

Please explain, thanks.

And what is your Wordpress application sending for cache headers? Nginx will generally obey the cache headers Cache-Control and Expires from the backend.

So you either need to have something like this: http://wordpress.org/extend/plugins/ngi … ntegrator/">http://wordpress.org/extend/plugins/nginx-proxy-cache-integrator/ (I haven't used that, but I made a small drupal module that would send the X-Accel-Expires=0 from the backend to keep nginx from caching logged in pages) and also do fastcgiignoreheaders Cache-Control Expires; so that the nginx cache doesn't obey those.

Or instead of all that junk, use 0.8.46 or later that have the new directives fastcgicachebypass and fastcginocache.

Brian, you may just be about to become my hero.

@brianmercer:

What are you trying to accomplish with all that stuff?

….

Please explain, thanks.

I am trying to add (PHP) fastcgi caching to WordPress (MU if possible, but am willing to take small steps). Think of me as a student, ready for your teaching :) Feel free to ignore any ignorant rubbish from previous post.

nginx version: nginx/0.8.53
built by gcc 4.4.3 (Ubuntu 4.4.3-4ubuntu5)
TLS SNI support enabled
configure arguments: --conf-path=/etc/nginx/nginx.conf --error-log-path=/var/log/nginx/error.log --pid-path=/var/run/nginx.pid --lock-path=/var/lock/nginx.lock --http-log-path=/var/log/nginx/access.log --http-client-body-temp-path=/var/lib/nginx/body --http-proxy-temp-path=/var/lib/nginx/proxy --http-fastcgi-temp-path=/var/lib/nginx/fastcgi --with-debug --with-http_stub_status_module --with-http_flv_module --with-http_ssl_module --with-http_dav_module --with-http_gzip_static_module --with-http_realip_module --with-mail --with-mail_ssl_module --with-ipv6 --add-module=/root/SERVER_BUILD/nginx-0.8.53/gnosek-nginx-upstream-fair-2131c73

Although I am a little geeky, and understand caching, some issues with caching (like dogpiling) - I'm more of a developer than a sysadmin and the nginx-fu hasn't quite sunk in with me yet.

I appreciate that caching the wp-admin pages is not a great idea (but again, small steps and all that).

This the non-cache nginx server{} WP config I am currently using on my non default sites:

server { 
  listen      1.2.3.4:80; 
  server_name www.mysite.com; 

  error_log  /var/log/nginx/www.mysite.com-error.log; 
  access_log /var/log/nginx/www.mysite.com-access.log; 

  root  /home/graq/sites/www.mysite.com; 

  location / { 
    try_files $uri $uri/ /index.php?q=$uri&$args; 
  } 

  location ~ \.php$ { 
    fastcgi_pass  unix:/usr/local/var/run/php-fpm.sock; 
    fastcgi_index index.php; 
    fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; 
    fastcgi_param PATH_INFO       $fastcgi_script_name; 
    include fastcgi_params; 
  } 
} 

In case you want to know about PHP

phpinfo()
PHP Version => 5.3.3

System => Linux paprika 2.6.32.16-linode28 #1 SMP Sun Jul 25 21:32:42 UTC 2010 i686
Build Date => Nov 16 2010 12:48:36
Configure Command =>  './configure'  '--with-config-file-path=/usr/local/lib/php' '--with-curl' '--enable-exif' '--with-gd' '--with-jpeg-dir' '--with-png-dir' '--with-zlib' '--with-xpm-dir' '--with-freetype-dir' '--with-t1lib' '--with-mcrypt' '--with-mhash' '--with-mysql=mysqlnd' '--with-mysqli=mysqlnd' '--with-pdo-mysql=mysqlnd' '--with-openssl' '--enable-sysvmsg' '--enable-wddx' '--with-xsl' '--enable-zip' '--with-bz2' '--enable-bcmath' '--enable-calendar' '--enable-ftp' '--enable-mbstring' '--enable-soap' '--enable-sockets' '--enable-sqlite-utf8' '--with-gettext' '--enable-shmop' '--with-xmlrpc' '--enable-dba' '--enable-sysvsem' '--enable-sysvshm' '--enable-fpm' '--with-fpm-user=www-data' '--with-fpm-group=www-data'

Give this a try:

  location ~ \.php$ {

    set $nocache "";
    if ($http_cookie ~ (comment_author_.*|wordpress_logged_in.*|wp-postpass_.*)) {
      set $nocache "Y";
    }

    fastcgi_pass  unix:/usr/local/var/run/php-fpm.sock;
    fastcgi_index index.php;
    fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
    include fastcgi_params;

    fastcgi_cache_use_stale error timeout invalid_header http_500;
    fastcgi_cache_key $host$request_uri;
    fastcgi_cache  WORDPRESS;
    fastcgi_cache_valid 200 1m;
    fastcgi_cache_bypass $nocache;
    fastcgi_no_cache $nocache;
  } 

:D It is a thing of beauty. Thank you. :mrgreen:

I have a few questions, if you know the answers:

1. It looks like it will work quite well with WordPressMU as well? I can supply my current WPMU if it needs tweaking.

2. The WP Plugin you mentioned earlier, 'just' adds header("X-Accel-Expires: 0"); if the cookie matches pregmatch('/wordpress(?!testcookie)|commentauthor|wp-postpass/', $key) . Which is already covered in your nginx snippet. However is there a header I can send in WP to trigger an update in nginx's cache? I'm imagining a site where all non-admin pages are cached, but (in a similar fashion to the 'edit page' option that often appears for admins) a link is added for admins to refresh the cache on an individual page. Plus there is probably a hook into the WP post update.

3. I liked the idea of playing with a cache key that allows for non-admin to get their own cached pages (e.g. subsribers/commentors). Is this a somewhat trivial exercise?

(sorry, I forgot a question I've been meaning to ask).

4. I thought the pages were cached into effectively static html? If that is the case, why is the PHP still run (see I told I didn't actually know what fastcgi_cache did)?

1. Since the $host is part of the key, it probably will. Test it out, let us know, we'll adjust as needed. I tested an nginx config for WP3.0 multisite but never used it for anything.

2. Yeah, that old module shouldn't be necessary with the 0.8.46+ directives.

There is a new module: http://wordpress.org/extend/plugins/ngi … che-purge/">http://wordpress.org/extend/plugins/nginx-proxy-cache-purge/ which requires nginx to be compiled with the cache purge contrib module. Selectively purging updated posts and the front page and feeds …that's definitely the next step, but I haven't tried it.

3. Dunno how practical that is. If one person makes a comment, do you want to save every page they visit afterward in case that same person revisits that exact page? Doesn't sound worthwhile. I can understand trying to cache portions of a site for all commenters, but not on an individual basis.

4. The pages are cached as static files in /var/cache/nginx and you can go view them. The filenames are an md5 hash of the cache_key. If someone visits the same page and the cached page is still valid, the request is not passed to the php backend.

@brianmercer:

1. Since the $host is part of the key, it probably will. Test it out, let us know, we'll adjust as needed. I tested an nginx config for WP3.0 multisite but never used it for anything. I've got WPMU (dir based) set up as follows:

server{
  .. as above..

  ## MU settings - starts
  server_name_in_redirect off;
  port_in_redirect off;

  rewrite ^.*/files/(.*) /wp-includes/ms-files.php?file=$1;
  if (!-e $request_filename) {
   rewrite ^.+?(/wp-.*) $1 last;
   rewrite ^.+?(/.*\.php)$ $1 last;
   rewrite ^ /index.php last;
  }
  ## MU settings - ends

  location / {
    try_files $uri $uri/ /index.php?q=$uri&$args;
  }

  location ~ \.php$ {
    set $nocache "";
    if ($http_cookie ~ (comment_author_.*|wordpress_logged_in.*|wp-postpass_.*)) {
      set $nocache "Y";
    }

    fastcgi_pass  unix:/usr/local/var/run/php-fpm.sock;
    fastcgi_index index.php;
    fastcgi_param CONTENT-LENGTH  $content_length;
    fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
    fastcgi_param PATH_INFO       $fastcgi_script_name;
    include fastcgi_params;

    fastcgi_cache_use_stale error timeout invalid_header http_500;
    fastcgi_cache_key       $host$request_uri;
    fastcgi_cache           WORDPRESS;
    fastcgi_cache_valid     200 2m;
    fastcgi_cache_bypass    $nocache;
    fastcgi_no_cache        $nocache;
  }
}

What I'm especially liking about this is that I could 'export' the whole .php section into an include file and reduce the size of the site config. Can be included by both standard and MU.

@brianmercer:

2. Yeah, that old module shouldn't be necessary with the 0.8.46+ directives.

There is a new module: http://wordpress.org/extend/plugins/ngi … che-purge/">http://wordpress.org/extend/plugins/nginx-proxy-cache-purge/ which requires nginx to be compiled with the cache purge contrib module. Selectively purging updated posts and the front page and feeds …that's definitely the next step, but I haven't tried it. I may just try this. Hopefully soon. Will post a follow up when I do.

@brianmercer:

3. Dunno how practical that is. If one person makes a comment, do you want to save every page they visit afterward in case that same person revisits that exact page? Doesn't sound worthwhile. I can understand trying to cache portions of a site for all commenters, but not on an individual basis. Yeah.. I think you are right.

@brianmercer:

4. The pages are cached as static files in /var/cache/nginx and you can go view them. The filenames are an md5 hash of the cachekey. If someone visits the same page and the cached page is still valid, the request is not passed to the php backend. What confused me was my own ignorance. When I first played with fastcgicache I stuck some error_log('hello'); statements in the WP theme files to determine whether I was getting cached hits or not. I now realise just how naive and wrong that is.

Thanks for your help Brian. Really appreciate it.

I am confused again.

I have added this configuration to 3 server{} blocks (2 standard WP 1 MU). Only the initial (default) server{} is caching.

Is this something that only works for 1 http{} block?

Hmmm…not sure why that would happen. Generally, you only have one http block. One cache should be enough for multiple server blocks.

I assume you have the fastcgicachepath defined at the http level in nginx.conf. Probably won't work anywhere else. And that you're using the same WORDPRESS zone for each server, and including the $host in the key to avoid collisions.

Can't think of anything. Paste the configs again if you like.

I am an idiot. Complete plum. The sites not caching have plugins installed that filter on this WP core function:

function wp_get_nocache_headers() {
        $headers = array(
                'Expires' => 'Wed, 11 Jan 1984 05:00:00 GMT',
                'Last-Modified' => gmdate( 'D, d M Y H:i:s' ) . ' GMT',
                'Cache-Control' => 'no-cache, must-revalidate, max-age=0',
                'Pragma' => 'no-cache',
        );

        if ( function_exists('apply_filters') ) {
                $headers = apply_filters('nocache_headers', $headers);
        }
        return $headers;
}

Doing a wget -S http://www.site2.com/ clearly shows
> HTTP request sent, awaiting response…

HTTP/1.1 200 OK

Server: nginx/0.8.53

Date: Sun, 28 Nov 2010 08:30:04 GMT

Content-Type: text/html; charset=UTF-8

Connection: close

X-Powered-By: PHP/5.3.3

Expires: Wed, 11 Jan 1984 05:00:00 GMT

Last-Modified: Sun, 28 Nov 2010 08:30:04 GMT

Cache-Control: no-cache, must-revalidate, max-age=0

Pragma: no-cache This seems like a massive reason for nginx not to cache my requests.

[SLAP]

Let me look into that before I go off half-cocked again.

Good , good.

fastcgi_ignore_headers Expires Pragma Cache-Control

Thank you! :D
@brianmercer:

Good , good.

fastcgi_ignore_headers Expires Pragma Cache-Control

From the docs (~~[http://wiki.nginx.org/HttpFcgiModule#fastcgiignoreheaders" target="blank">](http://wiki.nginx.org/HttpFcgiModule#fa … re_headers">http://wiki.nginx.org/HttpFcgiModule#fastcgiignore_headers]()

fastcgi_ignore_headers
syntax: fastcgi_ignore_headers name [name...]

context: http, server, location

This directive forbids processing of the named headers from the FastCGI-server reply. It is possible to specify headers like "X-Accel-Redirect", "X-Accel-Expires", "Expires" or "Cache-Control".

So Pragma is not valid. But that detracts nothing from your point. All three trial sites up and running with caching.

Nginx+fastcgi+PHP really does build a super webserver.

You are correct.

fastcgi_ignore_headers Expires Cache-Control;

should be enough. Apparently nginx ignores pragma. http://forum.nginx.org/read.php?2,2182,2183#msg-2183

@brianmercer:

There is a new module: http://wordpress.org/extend/plugins/ngi … che-purge/">http://wordpress.org/extend/plugins/nginx-proxy-cache-purge/ which requires nginx to be compiled with the cache purge contrib module. Selectively purging updated posts and the front page and feeds …that's definitely the next step, but I haven't tried it.
http://labs.frickle.com/nginxngxcache_purge/

  location ~ /purge(/.*) {
    access_log off;
    allow               127.0.0.1;
    deny                all;
    fastcgi_cache_purge WORDPRESS $host$1;
  }

I added the nginx module and installed the WP plugin. Works like a treat.