= An efficient CAPTCHA server


== Description

This server is built on Nginx and Memcached. It stores all the CAPTCHA image in
the memcached. When the new request cames, Nginx will reply a CAPTCHA page. If the
client passes the verification, He will be given a secure cookie. With this
cookie, client can visit all the resources in the server. 


== Component 

* The derivate of Nginx: ngx_openresty(http://openresty.org/).
* My secure cookie module(https://github.com/yaoweibin/nginx_secure_cookie_module).
* Memcached
* JCaptcha 2.0(http://jcaptcha.sourceforge.net/)


== Installation

=== Install the memcached
$wget http://memcached.googlecode.com/files/memcached-1.4.10.tar.gz
$tar zxvf memcached-1.4.10.tar.gz
$cd memcached-1.4.10
$./configure && make
$sudo make install
$/usr/local/bin/memcached -d

=== Generate the CAPTCHA image
$cd /path/to/captcha_server
$cd captcha
$./makeimg.sh # 10000 images will be created in the img directory
$ruby put_img.rb #You need the memcached gem packet

=== Install the Nginx
$wget http://agentzh.org/misc/nginx/ngx_openresty-1.0.10.24.tar.gz
$tar zxvf ngx_openresty-1.0.10.24.tar.gz
$cd ngx_openresty-1.0.10.24
$git clone git://github.com/yaoweibin/nginx_secure_cookie_module.git
$./configure  --with-debug --with-luajit \
        --add-module=nginx_secure_cookie_module
$make
$sudo make install

=== Copy the configure and pages
$cd /path/to/captcha_server
$cp conf/nginx.conf /path/to/nginx.conf
$cp html/* /path/to/html/   #this is your root directory

=== Start the Nginx
$sudo /usr/loca/nginx/sbin/nginx -c /path/to/nginx.conf