Saturday, April 19, 2008

Baking CakePHP with nginx

I've switched all my web server related infrastructure to nginx which is a high performance HTTP server (amongst other things) which blows apache out of the water (IMNSHO).

If you're a CakePHP user you'll know that it has some special rewriting requirements which can be found in $ROOT/.htaccess:

$ cat .htaccess

RewriteEngine on
RewriteRule ^$ app/webroot/ [L]
RewriteRule (.*) app/webroot/$1 [L]

Unfortunately this .htaccess file is an apache mechanism to achieve the URL rewriting that is required to get CakePHP to play nice. The apache rewrite rules do not translate directly to something nginx can use though so some work is required to get things going.

Being lazy (and believing that no problem I discover is unique to me) I had a look a round and found this article by Chris Hartjes which needed a some mods for it to work for my setup:

# CakePHP rewrite rules
location / {
root /opt/local/html/live_site;
index index.php;

# Serve static page immediately
if (-f $request_filename) {

if (!-f $request_filename) {
rewrite ^/(.+)$ /index.php?url=$1 last;

Here's my complete nginx.conf to give you an idea of how everything fits together:

user nobody;
worker_processes 1;

#error_log logs/error.log;
#error_log logs/error.log notice;
#error_log logs/error.log info;

#pid logs/;

events {
worker_connections 1024;

http {
include etc/nginx/mime.types;
default_type application/octet-stream;
server_names_hash_bucket_size 128;

sendfile on;
keepalive_timeout 20;
tcp_nodelay on;

server {
listen 80;
server_name localhost;
rewrite_log on;

#error_page 404 /404.html;
# redirect server error pages to the static page /50x.html
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root share/nginx/html;

# Serve static content directly with some caching goodness
location ~* ^.+.(jpg|jpeg|gif|css|png|js|ico)$ {
root /opt/local/html/live_site/app/webroot;
access_log off;
expires 1d;

# CakePHP rewrite rules
location / {
root /opt/local/html/live_site;
index index.php;

# Serve static pages immediately
if (-f $request_filename) {

# Rewrite all other URLs
if (!-f $request_filename) {
rewrite ^/(.+)$ /index.php?url=$1 last;

# Pass PHP scripts to FastCGI server listening on
location ~ \.php$ {
root /opt/local/html/live_site;
fastcgi_index index.php;
include /opt/local/etc/nginx/fastcgi_params;

Friday, April 18, 2008

PHP5 SimpleXML and CDATA

I am in the process of porting a rather large PHP4 application to PHP5 (just in time for PHP6, yes, yes, I know) for one of my customers. Most of the application is pure imperative programming so the switch has been rather painless.

Unfortunately (for me) they have made rather judicious use of the PHP4 domxml extension libraries which no longer exist in PHP5 (where they have been replaced with the dom extension).

Moving from domxml to dom was straight forward (looping over tags, tags, attributes and text inside tags are addresses differently) so I chose to simply re-write the code to use the new dom extensions instead of opting for a translation library like the one provided by Alexandre Alapetite.

One exception to this was the use of < !--[CDATA[...]]--> blocks which SimpleXML simply seemed to discard when creating a new object.

A quick look around Google (here, here and here) and I found what needed to be done to address SimpleXML's ignorant behaviour.

The SimpleXML constructor allows you to pass in extra libxml2 parameters which allow you to get further functionality out of the library. The one I was interested was of course:

Merge CDATA as text nodes

So, simply changing my constructor from:
$xml = new SimpleXMLElement($text)
$xml = new SimpleXMLElement($text, LIBXML_NOCDATA)
was all that was required for me to gain access to those < !--[CDATA[...]]--> structures.

Tuesday, April 1, 2008

Aspell, PSPELL, PHP and OS X

Until quite recently there was no way to use Aspell (via the PSPELL PHP libs) on an OS X host that was using the MacPorts system for package management.

This was simply because of the lack of a pspell variant for the php{45} packages.

Port of call
The ports system has the notion of a variant for packages that are conditional modifications of port installation behaviour.

There are two types of variants: user-selected variants and platform variants.

User-selected variants are options selected by a user when a port is installed while platform variants are selected automatically by MacPorts' base according to the OS or hardware platform (Darwin, FreeBSD, Linux, i386, PPC, etc.).

More stuff and less fluff
There are several ways of working this. The first would be to log a ticket at the MacPorts trac with a request to add the variant.

Depending on the package maintainer's load you may be a response pretty quickly. I've generally gotten something back within days of logging the ticket.

In the meantime your universe cannot come to a halt waiting for someone else to add the next greatest thing as a variant to your favourite package. So here's some manual steps to get things up and running in the meantime:

  • Install Aspell
  • Recompile and install PHP with the required PSPELL support
  • Check php to ensure the new PSPELL libs are active
  • Do a simple test to see if everything is working as it should

Install Aspell
I'll assume you're using MacPorts for your your package management on your OS X host.

Grab the aspell application, libs and whichever dictionaries catch your fancy:

$ sudo port install aspell aspell-dict-en

Be sure to install at least one dictionary or your spell checking days will be rather deflated.

Recompile and install PHP with the required PSPELL support
To manually add a compilation flag you need to edit the Portfile that comes with your installed PHP version. Mine is located at:


Edit the Portfile and add “–with-pspell=${prefix}” to configure.args. You can then re-ininstall PHP and it should now use the modified Portfile to compile PHP.

Check php to ensure the new PSPELL libs are active
Use the following script from the command line to determine if your PHP was re-installed with the required PSPELL bits enabled:

$ php -r 'phpinfo();' | grep PSpell
PSpell Support => enabled

Do a simple test to see if everything is working as it should
You should be able to just use the example from the PHP documentation page to ensure everything is fine:

$ cat /tmp/t_pspell.php

$ php -f /tmp/t_pspell.php
Sorry, wrong spelling

The packaging gods exist!
A few days after creating this ticket on the MacPorts trac I got a response from the package maintainer informing me that the variant had been added to all the relevant PHP packages.


If your ports distribution files are up-to-date you should now be able to do the following to see which variants are available for your PHP version of choice:

$ port info php5
php5 5.2.5, Revision 2, www/php5 (Variants: universal, darwin_6, darwin_7, macosx, apache, apache2, fastcgi, gmp, imap, pspell, tidy, mssql, snmp, macports_snmp, mysql3, mysql4, mysql5, oracle, postgresql, sqlite, ipc, pcntl, pear, readline, sockets)

PHP is a widely-used general-purpose scripting language that is especially suited for developing web sites, but can also be used for command-line scripting.

Library Dependencies: libxml2, libxslt, openssl, zlib, bzip2, libiconv, expat, gettext, tiff, mhash, libmcrypt, curl, pcre, jpeg, libpng, freetype
Platforms: darwin freebsd

Now that pspell is listed as a variant you can install PHP with this variant by doing the following, after removing previous PHP version:

$ sudo port install php5 +pspell

About Me

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I love solving real-world problems with code and systems (web apps, distributed systems and all the bits and pieces in-between).