Nginx-Lua-FastDFS-GraphicsMagick动态图片缩略图

公司使用FastDFS来当作图片服务器，客户端通过Nginx请求图片。某些情况下，客户端对请求的图片有尺寸要求，
如 http://10.100.1.145/group1/M00/00/18/CmQBkVsSjbiARQKhAAAHLpECb3c407.jpg_400x400.jpg。
这时我们可以使用GraphicsMagick工具动态的修改图片以满足客户端的需求。
这里使用lua脚本，调用GraphicsMagick的gm命令动态处理图片。

FastDFS+Nginx的安装配置步骤请见：https://blog.csdn.net/danielzhou888/article/details/80563355

安装包来源请自行百度，谢谢。

整体思路:

1、首先服务器需要有lua环境
2、Nginx扩展支持lua，可调用lua脚本
3、lua脚本中定义gm命令及参数

安装配置:

1、安装lua环境

tar zxvf LuaJIT-2.0.2.tar.gz
cd LuaJIT-2.0.2
make && make install

2、配置lua环境变量

export LUAJIT_LIB=/usr/local/lib
export LUAJIT_INC=/usr/local/include/luajit-2.0

3、安装GraphicsMagick

tar zxvf GraphicsMagick-1.3.21.tar.gz
cd GraphicsMagick
./configure –prefix=/data/local/GraphicsMagick –enable-shared
make && make install

查看GraphicsMagick 支持的文件类型:
/data/local/GraphicsMagick/bin/gm -version

Feature Support:
Native Thread Safe yes
Large Files (> 32 bit) yes
Large Memory (> 32 bit) yes
BZIP yes
DPS no
FlashPix no
FreeType no
Ghostscript (Library) no
JBIG no
JPEG-2000 no
JPEG yes
Little CMS no
Loadable Modules no
OpenMP yes (201107)
PNG yes
TIFF no
TRIO no
UMEM no
WebP no
WMF no
X11 no
XML no
ZLIB yes

Host type: x86_64-unknown-linux-gnu
若PNG、JPEG等不支持，可以在编译GraphicsMagick的时候，使用 –with-png=yes

4、准备lua模块

ngx_devel_kit-0.2.18.tar.gz
v0.8.6.tar.gz（lua-nginx-module-0.8.6

5、安装Nginx

tar zxvf nginx-1.4.2.tar.gz
cd nginx-1.4.2
./configure —prefix=/usr/local/nginx —add-module=lua-nginx-module-0.8.6 —add-module=ngx_devel_kit-0.2.18
make && make install

测试nginx扩展lua是否正常:

location /test {
default_type text/html;
content_by_lua ’
ngx.say(“hello world”)
ngx.log(ngx.ERR,”err err”)
‘;
}
若返回hello world即说明正常

6、启动Nginx

若出错，如/usr/local/nginx/sbin/nginx: error while loading shared libraries: libluajit-5.1.so.2: cannot open shared object file: No such file or directory
请按如下操作:
find / -name libluajit-5.1.so.2

ln -s /usr/local/lib/libluajit-5.1.so.2 /usr/lib64/libluajit-5.1.so.2

7、lua脚本ImageResizer.lua

local command = “/data/local/GraphicsMagick/bin/gm convert ” .. ngx.var.request_filepath .. ” -resize ” .. ngx.var.width .. “x” .. ngx.var.height .. ” +profile \”*\” ” .. ngx.var.request_filepath .. “_” .. ngx.var.width .. “x” .. ngx.var.height .. “.” ..
ngx.var.ext;os.execute(command);
ngx.exec(ngx.var.request_uri);
Nginx配置请见nginx.conf

user  root;
worker_processes  1;

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

#pid        logs/nginx.pid;


events {
    worker_connections  1024;
}


http {
    include       mime.types;
    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    #access_log  logs/access.log  main;

    sendfile        on;
    #tcp_nopush     on;

    #keepalive_timeout  0;
    keepalive_timeout  65;

    #gzip  on;
    lua_package_path "/usr/local/nginx/conf/lua/?.lua;;";

server {
    listen       80;
    server_name localhost;

    location /group1/M00 {
        root /home/fastdfs/fastdfs_storage_data/data;

    if ($uri ~* ^/group1/M00(.+\.(jpg|jpeg|gif|png))_(\d+)x(\d+)\.(jpg|jpeg|gif|png)) {       
                add_header X-Powered-By 'Lua GraphicsMagick';
                add_header file-path $request_filename;
                lua_code_cache on;
                set $request_filepath /home/fastdfs/fastdfs_storage_data/data$1;
                set $width $3;
                set $height $4;
                set $ext $5;
    }

        if (!-f $request_filename) {
            content_by_lua_file conf/lua/ImageResizer.lua;
    }
    }
}

    # another virtual host using mix of IP-, name-, and port-based configuration
    #
    #server {
    #    listen       8000;
    #    listen       somename:8080;
    #    server_name  somename  alias  another.alias;

    #    location / {
    #        root   html;
    #        index  index.html index.htm;
    #    }
    #}


    # HTTPS server
    #
    #server {
    #    listen       443 ssl;
    #    server_name  localhost;

    #    ssl_certificate      cert.pem;
    #    ssl_certificate_key  cert.key;

    #    ssl_session_cache    shared:SSL:1m;
    #    ssl_session_timeout  5m;

    #    ssl_ciphers  HIGH:!aNULL:!MD5;
    #    ssl_prefer_server_ciphers  on;

    #    location / {
    #        root   html;
    #        index  index.html index.htm;
    #    }
    #}

}

lua配置请见ImageResizer.lua

if(ngx.var.height ~= '' and ngx.var.width ~= '') then
    height = tonumber(ngx.var.height);
    width = tonumber(ngx.var.width);
    if(height > 1000) then
        height = 1000
    end
    if(width > 1000) then
        height = 1000
    end
    local command = "/usr/local/GraphicsMagick/bin/gm convert " .. ngx.var.request_filepath .. " -resize " .. width .. "x" .. height .. " +profile \"*\" " .. ngx.var.request_filepath .. "_" .. ngx.var.width .. "x" .. ngx.var.height .. "." .. ngx.var.ext;
    os.execute(command);
    ngx.exec(ngx.var.request_uri);
else
    ngx.exit(ngx.HTTP_NOT_FOUND);
end