IP address checker

Random idea I came up when reading nginx mailing list. A very simple way to set up external IP address checker using nginx on a remote server.

location = /ip {
    default_type text/plain;
    types { }

    return 200 $remote_addr\n;

Accessing /ip will then return the current external IP address. A more fancy output like JSON is possible as well.


A few years ago I wrote a php script to provide better autoindex within nginx. I used it for quite a long period until I rewrote it in Ruby/Sinatra. But then I figured the setup for it is overly complicated just for simple task. And takes additional memory. I always have php-fpm running anyway so it’s free.

And so I decided to take up the old php script and fix it up. Unfortunately there isn’t other language as easy to setup for web as php which is why I fixed it instead of rewriting in some other languages (or keeping it ruby). The “fixed” version is still pretty much imperative-style but hey, it works.

Only tested with nginx.

PSA: Never trust external X-Forwarded-For

For god knows how long, proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; is one of the line usually included in nginx config snippet for proxying to a unicorn (Rails) backend.

…which is something you should never do unless you have another load balancer in front of the nginx being configured.

That line basically tells nginx to append $remote_addr to whatever X-Forwarded-For value currently set. It is only useful when your nginx is behind other load balancer which set up its own (hopefully correctly) X-Forwarded-For. It should be set explicitly to $remote_addr for any external-facing proxy. Otherwise fun things will happen.

An Attempt to Update moebooru Engine

If you didn’t know, the current moebooru running on oreno.imouto is using ancient version of many things. It also uses a custom lighty module (mod_zipfile) which doesn’t seem to be available anywhere.

I’ve updated it with latest Rails 2.x and made it compatible with nginx. Mostly. You can see it running here.

The plans:

  • Upgrade to Ruby 1.9.
  • Update all plugins.
  • Update anything deprecated.
  • Migrate to Bundler.
  • Use RMagick instead of custom ruby-gd plugin.
  • Use RMagick instead of calling jhead binary.
  • And more!

We’ll see if I can actually finish this one. Grab the source here. Yeah, I’m using Mercurial for a Rails project.

nginx – gzip all the text

During my migration to other server, I recreated some of my configs and enabled gzip compression for most file types. Here’s the relevant config:

gzip on;
gzip_vary on;
gzip_disable "msie6";
gzip_comp_level 6;
gzip_proxied expired no-cache no-store private auth;
gzip_types text/plain text/xml application/xml application/json application/x-javascript text/javascript text/css;

It should cover most text-based content one will ever serve over the web. Probably.

nginx/php single config for SSL and non-SSL connection

This morning I noticed I haven’t upgraded WordPress MU Domain Mapping plugin to the latest version. It supposedly brings better SSL support. And after upgrading I couldn’t log in to my mapped domain blogs (e.g. this blog). Wasn’t it a great way to start my morning?

After some digging, I found out the problem was because I don’t have one PHP(?) parameter – HTTPS – passed properly. It should set to True whenever one is using SSL connection otherwise there’s no way the PHP process can know if the connection is secure or not. Previous version of WPMUDM have a bug in which skips SSL check but in turn enables using HTTPS even without such parameter. Decided it’s my fault (I believe it would completely breaks phpMyAdmin), adding the parameter then I did.

But it’s not that simple: I’m using unified config for both my SSL and non-SSL connection’s PHP include. Splitting the config would make the duplication worse (it’s already relatively bad as it is) so that’s not an option. Using the evil if is also not a solution since it doesn’t support setting fastcgi_param inside it.

Then the solution hit me. The map module – a module specifically made for things like this and to avoid usage of if. I tested it and indeed worked as expected.

Here be the config:

http {
  map $scheme $fastcgi_https {
    https 1;
    default 0;
  server {
    location ~ .php$ {
      fastcgi_param HTTPS $fastcgi_https;

And WordPress MU Domain Mapping is now happy.

Update 2012-02-20: nginx version 1.1.11 and up now have $https variable. No need to have that map anymore.

WordPress Multisite with nginx (subdomain/wildcard domain ver.)

WordPress Multisite, previously known as WordPress MU (Multi User), is an application which allows hosting multiple WordPress blogs with just one installation. Instead of creating copies of WordPress for each users’ blogs, one can use one installation of Multisite to be used by multiple users, each with their own blogs. Personal/custom domain is also possible as used for this blog (this blog’s master site is genshiken-itb.org). Too bad, the official documentation only provided guide for installing on Apache. If you haven’t known, I usually avoid Apache – I simply more proficient with nginx. Of course, this blog is also running on nginx therefore it’s perfectly possible to run WordPress Multisite on nginx.

At any rate, reading the official documentation is still a must and this post will only cover the nginx version of Apache-specific parts (namely Apache Virtual Hosts and Mod Rewrite and .htaccess and Mod Rewrite) and only for subdomain install. Subdirectory one will or will not follow some time later.

Assuming you have working nginx and php-cgi (with process manager like php-fpm or supervisord), for starter you’ll want to create a specific file for this WP install. Let’s say this file named app-wordpress.conf. Obviously you have put WordPress installation somewhere in your server. In this example I put the files in /srv/http/genshiken-itb.org/.php/wordpress. Its content:

client_max_body_size 100m;
root /srv/http/genshiken-itb.org;
location /. { return 404; }
location / {
  root /srv/http/genshiken-itb.org/.php/wordpress;
  index index.php;
  try_files $uri $uri/ /index.php?$args;
  rewrite ^/files/(.*) /wp-includes/ms-files.php?file=$1;
  location ~ .php$ {
    try_files $uri =404;
    fastcgi_pass unix:/tmp/php-genshiken.sock;
    fastcgi_read_timeout 600;
    fastcgi_send_timeout 600;
    fastcgi_index index.php;
    fastcgi_param SCRIPT_FILENAME $request_filename;
    include fastcgi_params;

Simple enough. Actually, it’s exact same with normal WordPress install except one extra line:

rewrite ^/files/(.*) /wp-includes/ms-files.php?file=$1;

And you’re set. Note that I set fastcgi timeouts higher than default to work around the slow performance of Amazon EC2 Micro Instance. Should only needed on network upgrade and massive blog import.

Anyway, in your main nginx.conf file, put:

server {
  listen 80;
  server_name *.genshiken-itb.org;
  include app-wordpress.conf;

In proper place. The usefulness of separate file for WordPress configuration will become apparent once you want to tweak performance for some blogs. I’ll explain that later if I feel like to.

no-www for nginx

If you happen to be in no-www camp and want to redirect people accessing www.whateverdomain.com to the no-www version but have lots of domain, instead of writing one by one and you’re not keen in using config generator (I’m not), you can use this:

server {
  listen 80;
  listen [::]:80 ipv6only=on;
  server_name ~^www.(?<domain>.+)$;
  rewrite ^ $scheme://$domain$request_uri? permanent;
  access_log /var/log/nginx/access-no_www.log;

Remove listen [::]:80 ipv6only=on; if you’re not using IPv6 and adjust the log file path to wherever you want (or just turn off or remove it altogether).

Note that this trick doesn’t work well with HTTPS/SSL domains since you’ll get big fat warning about incorrect domain name in certificate or about self-signed certificate if you’re using wildcard one.