Nginx and PHP-FastCGI on Debian 6 (Squeeze)

Nginx and PHP-FastCGI on Debian 6 (Squeeze)

Published: Monday, May 9th, 2011 by Phil Paradis

The nginx web server is a fast, lightweight server designed to efficiently handle the needs of both low and high traffic websites. Although commonly used to serve static content, it's quite capable of handling dynamic pages as well. This guide will help you get nginx up and running with PHP via FastCGI on your Debian 6 (Squeeze) Linux VPS.

It is assumed that you've already followed the steps outlined in our getting started guide. These steps should be performed via a root login to your Linode VPS over SSH.

Contents

Set the Hostname

Before you begin installing and configuring the components described in this guide, please make sure you've followed our instructions for setting your hostname. Issue the following commands to make sure it is set properly:

hostname

hostname -f 

The first command should show your short hostname, and the second should show your fully qualified domain name (FQDN).

Install Required Packages

Issue the following commands to update your system and install the nginx web server, PHP, and compiler tools:

apt-get update

apt-get upgrade

apt-get install nginx php5-cli php5-cgi spawn-fcgi 

Configure Virtual Hosting

Create Directories

In this guide, the domain "example.com" is used as an example site. You should substitute your own domain name in the configuration steps that follow. First, create directories to hold content and log files:

mkdir -p /srv/www/www.example.com/public_html

mkdir /srv/www/www.example.com/logs

chown -R www-data:www-data /srv/www/www.example.com 

UNIX Sockets Configuration Example

Next, you'll need to define the site's virtual host file. This example uses a UNIX socket to connect to fcgiwrap. Be sure to change all instances of "example.com" to your domain name.

File:/etc/nginx/sites-available/www.example.com

server {

　　server_name www.example.comexample.com; 

　　access_log /srv/www/www.example.com/logs/access.log; 

　　error_log /srv/www/www.example.com/logs/error.log;

　　root /srv/www/www.example.com/public_html;

　　location / {

　　　　index index.htmlindex.htm;

　　}

　　location ~ \.php$ {

　　　　include /etc/nginx/fastcgi_params;

　　　　fastcgi_passunix:/var/run/php-fastcgi/php-fastcgi.socket;

　　　　fastcgi_index index.php;

　　　　fastcgi_param SCRIPT_FILENAME /srv/www/www.example.com/public_html$fastcgi_script_name;

　　}

} 

Create a file named /usr/bin/php-fastcgi with the following contents:

File:/usr/bin/php-fastcgi

#!/bin/bash

FASTCGI_USER=www-data

FASTCGI_GROUP=www-data

SOCKET=/var/run/php-fastcgi/php-fastcgi.socket

PIDFILE=/var/run/php-fastcgi/php-fastcgi.pid

CHILDREN=6 PHP5=/usr/bin/php5-cgi

/usr/bin/spawn-fcgi -s $SOCKET -P $PIDFILE -C $CHILDREN -u $FASTCGI_USER -g $FASTCGI_GROUP -f $PHP5

Make it executable by issuing the following command:

chmod +x /usr/bin/php-fastcgi 

TCP Sockets Configuration Example

Alternately, you may wish to use TCP sockets instead. If so, modify your nginx virtual host configuration file to resemble the following example. Again, make sure to replace all instances of "example.com" with your domain name.

File:/etc/nginx/sites-available/www.example.com

server {

　　server_name www.example.com example.com; 

　　access_log /srv/www/www.example.com/logs/access.log;

　　error_log /srv/www/www.example.com/logs/error.log;

　　root /srv/www/www.example.com/public_html;

　　location / {

　　　　index  index.html index.htm;

　　}

　　location ~ \.php$ {

　　　　include /etc/nginx/fastcgi_params;

　　　　fastcgi_pass 127.0.0.1:9000;

　　　　fastcgi_index index.php;

　　　　fastcgi_param SCRIPT_FILENAME /srv/www/www.example.com/public_html$fastcgi_script_name;

　　}

} 

Create a file named /usr/bin/php-fastcgi with the following contents:

File:/usr/bin/php-fastcgi

#!/bin/bash 

FASTCGI_USER=www-data 

FASTCGI_GROUP=www-data 

ADDRESS=127.0.0.1 PORT=9000 

PIDFILE=/var/run/php-fastcgi/php-fastcgi.pid 

CHILDREN=6 

PHP5=/usr/bin/php5-cgi  

/usr/bin/spawn-fcgi -a $ADDRESS -p $PORT -P $PIDFILE -C $CHILDREN -u $FASTCGI_USER -g $FASTCGI_GROUP -f $PHP5 

Make it executable by issuing the following command:

chmod +x /usr/bin/php-fastcgi 

Important Security Considerations

If you're planning to run applications that support file uploads (images, for example), the above configurations may expose you to a security risk by allowing arbitrary code execution. The short explanation for this behavior is that a properly crafted URI which ends in ".php", in combination with a malicious image file that actually contains valid PHP, can result in the image being processed as PHP.

To mitigate this issue, you may wish to modify your configuration to include a try_files directive. Please note that this fix requires nginx and the php-fcgi workers to reside on the same server.

location ~ \.php$ {

　　try_files $uri =404;

　　include /etc/nginx/fastcgi_params;

　　fastcgi_pass unix:/var/run/php-fastcgi/php-fastcgi.socket;

　　fastcgi_index index.php;

　　fastcgi_param SCRIPT_FILENAME /srv/www/www.example.com/public_html$fastcgi_script_name;

} 

Additionally, it's a good idea to secure any upload directories your applications may use. The following configuration excerpt demonstrates securing an "/images" directory.

location ~ \.php$ {

　　include /etc/nginx/fastcgi_params;

　　if ($uri !~ "^/images/") {

　　　　fastcgi_pass unix:/var/run/php-fastcgi/php-fastcgi.socket;

　　}

　　fastcgi_index index.php;

　　fastcgi_param SCRIPT_FILENAME /srv/www/www.example.com/public_html$fastcgi_script_name;

} 

Enable and Start Services

Issue the following commands to enable the site:

cd /etc/nginx/sites-enabled/

ln -s /etc/nginx/sites-available/www.example.com 

Create a file named /etc/init.d/php-fastcgi with the following contents:

File:/etc/init.d/php-fastcgi

#!/bin/bash

PHP_SCRIPT=/usr/bin/php-fastcgi

FASTCGI_USER=www-data

FASTCGI_GROUP=www-data

PID_DIR=/var/run/php-fastcgi

PID_FILE=/var/run/php-fastcgi/php-fastcgi.pid

RET_VAL=0

case "$1" in

　　start)

　　　　if [[ ! -d $PID_DIR ]]

　　　　then

　　　　　　mkdir $PID_DIR

　　　　　　chown $FASTCGI_USER:$FASTCGI_GROUP $PID_DIR

　　　　　　chmod 0770 $PID_DIR

　　　　fi

　　　　if [[ -r $PID_FILE ]]

　　　　then

　　　　　　echo "php-fastcgi already running with PID `cat $PID_FILE`"

　　　　　　RET_VAL=1

　　　　else

　　　　　　$PHP_SCRIPT

　　　　　　RET_VAL=$?

　　　　fi

　　;;

　　stop)

　　　　if [[ -r $PID_FILE ]]

　　　　then

　　　　　　kill `cat $PID_FILE`

　　　　　　rm $PID_FILE

　　　　　　RET_VAL=$?

　　　　　　else  echo "Could not find PID file $PID_FILE"

　　　　　　RET_VAL=1

　　　　fi

　　;;

　　restart)

　　　　if [[ -r $PID_FILE ]]

　　　　then  kill `cat $PID_FILE`

　　　　　　rm $PID_FILE

　　　　　　RET_VAL=$?

　　　　else

　　　　　　echo "Could not find PID file $PID_FILE"

　　　　fi

　　　　$PHP_SCRIPT

　　　　RET_VAL=$?

　　;;

　　status)

　　　　if [[ -r $PID_FILE ]]

　　　　then

　　　　　　echo "php-fastcgi running with PID `cat $PID_FILE`"

　　　　　　RET_VAL=$?

　　　　else

　　　　　　echo "Could not find PID file $PID_FILE, php-fastcgi does not appear to be running"

　　　　fi

　　;;

　　*)

　　　　echo "Usage: php-fastcgi {start|stop|restart|status}"

　　　　RET_VAL=1

　　;;

esac

exit $RET_VAL 

Start php-fastcgi and nginx by issuing the following commands:

chmod +x /etc/init.d/php-fastcgi

update-rc.d php-fastcgi defaults

/etc/init.d/php-fastcgi start

/etc/init.d/nginx start 

Test PHP with FastCGI

Create a file called "test.php" in your site's "public_html" directory with the following contents:

File:/srv/www/example.com/public_html/test.php

<?php phpinfo(); ?> 

When you visit http://www.example.com/test.php in your browser, the standard "PHP info" output is shown. Congratulations, you've configured the nginx web server to use PHP-FastCGI for dynamic content!

More Information

You may wish to consult the following resources for additional information on this topic. While these are provided in the hope that they will be useful, please note that we cannot vouch for the accuracy or timeliness of externally hosted materials.