nginx+lua_nginx+GraphicsMagick生成实时缩略图

暂做笔记，带后续验证通过后，再补充 1、2、3 步。

一、安装 lua

首先确认是否安装 readline

  yum -y install readline-devel ncurses-devel

进入页面：http://www.lua.org/download.html

wget http://www.lua.org/ftp/lua-5.3.1.tar.gz  
 
tar zxvf lua-5.3..tar.gz 
 
#进入解压目录
make linux && make install

wget http://luajit.org/download/LuaJIT-2.0.4.tar.gz
tar zxvf LuaJIT-2.0..tar.gz
cd LuaJIT-2.0.
make && make install

ln -s /usr/local/lib/libluajit-5.1.so. /lib64/libluajit-5.1.so.
export LUAJIT_LIB=/usr/local/lib
export LUAJIT_INC=/usr/local/include/luajit-2.0/

二、安装 GraphicsMagick

进入页面：http://www.graphicsmagick.org/1.3/download.html

tar zxvf GraphicsMagick-1.3..tar.gz
cd GraphicsMagick-1.3.
./configure  --prefix=/usr/local/graphicsmagick
make && make install
 
#验证

/usr/local/graphicsmagick/bin/gm version

三、安装nginx

进入页面：http://tengine.taobao.org/opensource_cn.html

./configure --prefix=/usr/local/nginx \
            --dso-path=/usr/local/nginx/modules \
            --with-http_realip_module \
            --with-http_gzip_static_module \
            --with-http_stub_status_module \
            --with-http_concat_module \
            --with-http_lua_module \
            --with-pcre=/usr/local/src/pcre-8.37\
            --with-zlib=/usr/local/src/zlib-1.2.\
            --with-openssl=/usr/local/src/openssl-1.0.0s\
            --http-proxy-temp-path=/var/tmp/nginx/proxy_temp \
            --http-fastcgi-temp-path=/var/tmp/nginx/fastcgi_temp \
            --http-uwsgi-temp-path=/var/tmp/nginx/uwsgi_temp \
            --http-scgi-temp-path=/var/tmp/nginx/cgi_temp \
            --http-client-body-temp-path=/var/tmp/nginx/client_body_temp \
            --http-log-path=/var/log/nginx/access.log \
            --error-log-path=/var/log/nginx/error.log\
            --with-ld-opt="-Wl,-rpath,$LUAJIT_LIB"
 
make && make install
 
#启动nginx
#测试配置文件
/usr/local/nginx/sbin/nginx -t
 
#启动
/usr/local/nginx/sbin/nginx 

设置开机启动

vi /etc/rc.d/init.d/nginx 

#!/bin/bash
# Tengine Startup script# processname: nginx
# chkconfig: -
# description: nginx is a World Wide Web server. It is used to serve
# pidfile: /var/run/nginx.pid
# config: /usr/local/nginx/conf/nginx.conf
nginxd=/usr/local/nginx/sbin/nginx
nginx_config=/usr/local/nginx/conf/nginx.conf
nginx_pid=/usr/local/nginx/logs/nginx.pid
RETVAL=
prog="nginx"
# Source function library.
. /etc/rc.d/init.d/functions
# Source networking configuration.
. /etc/sysconfig/network
# Check that networking is up.
[ ${NETWORKING} = "no" ] && exit
[ -x $nginxd ] || exit
# Start nginx daemons functions.
start() {
if [ -e $nginx_pid ];then
echo "tengine already running...."
exit
fi
echo -n $"Starting $prog: "
daemon $nginxd -c ${nginx_config}
RETVAL=$?
echo
[ $RETVAL =  ] && touch /var/lock/subsys/nginx
return $RETVAL
}
# Stop nginx daemons functions.
stop() {
echo -n $"Stopping $prog: "
killproc $nginxd
RETVAL=$?
echo
[ $RETVAL =  ] && rm -f /var/lock/subsys/nginx /usr/local/nginx/logs/nginx.pid
}
reload() {
echo -n $"Reloading $prog: "
#kill -HUP `cat ${nginx_pid}`
killproc $nginxd -HUP
RETVAL=$?
echo
}
# See how we were called.
case "$1" in
start)
start
;;
stop)
stop
;;
reload)
reload
;;
restart)
stop
start
;;
 
status)
status $prog
RETVAL=$?
;;
*)
echo $"Usage: $prog {start|stop|restart|reload|status|help}"
exit
esac
exit $RETVAL

保存退出

chmod  /etc/rc.d/init.d/nginx   #赋予文件执行权限
chkconfig  --level  nginx on   #设置开机启动
service nginx start

四、配置 nginx

nginx.conf

http
   {
        lua_package_path '/usr/local/openresty/nginx/lua/?.lua;;';
 
        server {
                listen       ;
                server_name  img.rhythmk.org;
                root  /home/wwwroot/static/image;
 
                #对类似_100x100.gif/jpg/png/jpeg进行缩略图处理
                location ~* _([-]+)x([-]+)\.(gif|jpg|png|jpeg)$ {                 #匹配文件名规则
                        root  /home/wwwroot/static/image;                             #站点根目录
                        set $image_root /home/wwwroot/static/image;                   #图片目录
                        set $thumbnail_root /home/wwwroot/static/thumbnail;           #缩略图存放目录
                        #如果缩略图文件存在，直接返回
                        set $file $thumbnail_root$uri;
                        if (-f $file) {
                                rewrite ^/(.*)$ /thumbnail/$ last;
                        }
                        #如果缩略图文件不存在，则应用缩略图模块处理
                        if (!-f $file) {
                                rewrite_by_lua_file lua/thumbnail.lua;
                        }
                }
         }
 
     #include conf/*.conf;
}

lua/thumbnail.lua

    local index = string.find(ngx.var.uri, "([0-9]+)x([0-9]+)");
    local originalUri = string.sub(ngx.var.uri, , index-);
    local area = string.sub(ngx.var.uri, index);
    index = string.find(area, "([.])");
    area = string.sub(area, , index-);  
 
    local image_sizes = {"80x80", "800x600", "40x40"};
    function table.contains(table, element)
       for _, value in pairs(table) do
          if value == element then
             return true
          end
       end
       return false
    end  
 
    if table.contains(image_sizes, area) then
        local command = "gm convert " .. ngx.var.image_root .. originalUri .. " -thumbnail " .. area .. " -background gray -gravity center -extent " .. area .. " " .. ngx.var.file;
        os.execute(command);
        ngx.req.set_uri(ngx.var.uri, true);
    else
        ngx.exit();
    end;