在做网站尤其是以内容为主的过程中，常常会遇到一张图片各种地方都要引用，且每个引用的地方要求的图片尺寸都不一样的。
一般中大型的网站都会对这一类的图片做自动裁剪功能。本文介绍在centos6操作系统上，采用nginx、lua和GraphicsMagick工具简单实现图片的自动裁剪功能。其中nginx负责展示图片和调度lua脚本，GraphicsMagick负责对原图进行裁剪。
一、基础软件包安装
groupadd www
useradd -g www www -s /bin/false
yum -y install epel-release git gcc gcc-c++ zlib zlib-devel openssl openssl-devel pcre pcre-devel libpng libjpeg libpng-devel libjpeg-devel ghostscript libtiff libtiff-devel freetype freetype-devel readline-devel ncurses-devel wget
二、下载相关软件
其中nginx-http-concat和echo-nginx-module模块非必须
wget http://nginx.org/download/nginx-1.8.0.tar.gz
wget http://luajit.org/download/LuaJIT-2.0.4.tar.gz
wget http://zlib.net/zlib-1.2.8.tar.gz
wget http://www.lua.org/ftp/lua-5.3.1.tar.gz
wget ftp://ftp.graphicsmagick.org/pub/GraphicsMagick/1.3/GraphicsMagick-1.3.18.tar.gz
git clone https://github.com/alibaba/nginx-http-concat.git
git clone https://github.com/simpl/ngx_devel_kit.git
git clone https://github.com/openresty/echo-nginx-module.git
git clone https://github.com/openresty/lua-nginx-module.git
三、编译安装nginx、GraphicsMagick
tar -zxf nginx-1.8.0.tar.gz
tar -zxf LuaJIT-2.0.4.tar.gz
tar -zxf zlib-1.2.8.tar.gz
cd LuaJIT-2.0.4
make
make install
export LUAJIT_LIB=/usr/local/lib
export LUAJIT_INC=/usr/local/include/luajit-2.0
ln -s /usr/local/lib/libluajit-5.1.so.2 /lib64/libluajit-5.1.so.2
cd ..
tar zxvf lua-5.3.1.tar.gz
cd lua-5.3.1
make linux && make install
cd ..
tar zxvf GraphicsMagick-1.3.18.tar.gz
cd GraphicsMagick-1.3.18
./configure --prefix=/usr/local/GraphicsMagick --enable-shared
make && make install
cd ..
cd nginx-1.8.0
./configure --prefix=/usr/local/nginx
--user=www
--group=www
--with-http_ssl_module
--with-http_realip_module
--with-http_sub_module
--with-http_flv_module
--with-http_dav_module
--with-http_gzip_static_module
--with-http_stub_status_module
--with-http_addition_module
--with-http_spdy_module
--with-pcre
--with-zlib=../zlib-1.2.8
--add-module=../nginx-http-concat
--add-module=../lua-nginx-module
--add-module=../ngx_devel_kit
--add-module=../echo-nginx-module
--with-ld-opt=-Wl,-rpath,$LUAJIT_LIB
make && make install
创建Nginx日志目录
mkdir -p /data/logs
chmod +w /data/logs
chown -R www:www /data/logs
创建Nginx配置文件
在/usr/local/nginx/conf/目录中创建nginx.conf文件：
>/usr/local/nginx/conf/nginx.conf
vi /usr/local/nginx/conf/nginx.conf
输入以下内容：
#####################################################################################################
user www www;
worker_processes 8;
error_log /data/logs/nginx_error.log crit;
pid /usr/local/nginx/nginx.pid;
#Specifies the value for maximum file descriptors that can be opened by this process.
worker_rlimit_nofile 65535;
events
{
use epoll;
worker_connections 65535;
}
http
{
include mime.types;
default_type application/octet-stream;
#charset gb2312;
server_names_hash_bucket_size 128;
client_header_buffer_size 32k;
large_client_header_buffers 4 32k;
client_max_body_size 8m;
sendfile on;
tcp_nopush on;
keepalive_timeout 60;
tcp_nodelay on;
fastcgi_connect_timeout 300;
fastcgi_send_timeout 300;
fastcgi_read_timeout 300;
fastcgi_buffer_size 64k;
fastcgi_buffers 4 64k;
fastcgi_busy_buffers_size 128k;
fastcgi_temp_file_write_size 128k;
gzip on;
gzip_min_length 1k;
gzip_buffers 4 16k;
gzip_http_version 1.0;
gzip_comp_level 2;
gzip_types text/plain application/x-javascript text/css application/xml;
gzip_vary on;
#limit_zone crawler $binary_remote_addr 10m;
include vhosts/*.conf;
}
#####################################################################################################
创建lua目录和lua脚本
mkdir /usr/local/nginx/lua
vi /usr/local/nginx/lua/cropSize.lua
#####################################################################################################
-- 根据输入长和宽的尺寸裁切图片
-- 检测路径是否目录
local function is_dir(sPath)
if type(sPath) ~= "string" then return false end
local response = os.execute("cd " .. sPath)
if response == 0 then
return true
end
return false
end
-- 文件是否存在
function file_exists(name)
local f = io.open(name, "r")
if f ~= nil then io.close(f) return true else return false end
end
-- 获取文件路径
function getFileDir(filename)
return string.match(filename, "(.+)/[^/]*%.%w+$") --*nix system
end
-- 获取文件名
function strippath(filename)
return string.match(filename, ".+/([^/]*%.%w+)$") -- *nix system
end
--去除扩展名
function stripextension(filename)
local idx = filename:match(".+()%.%w+$")
if (idx) then
return filename:sub(1, idx - 1)
else
return filename
end
end
--获取扩展名
function getExtension(filename)
return filename:match(".+%.(%w+)$")
end
-- 开始执行
-- ngx.log(ngx.ERR, getFileDir(ngx.var.img_file));
local gm_path = ‘/usr/local/GraphicsMagick/bin/gm‘
-- check image dir
if not is_dir(getFileDir(ngx.var.img_file)) then
os.execute("mkdir -p " .. getFileDir(ngx.var.img_file))
end
-- ngx.log(ngx.ERR,ngx.var.img_file);
-- ngx.log(ngx.ERR,ngx.var.request_filepath);
-- 裁剪后保证等比缩图 （缺点：裁剪了图片的一部分）
-- gm convert cropSize.jpg -thumbnail 300x300^ -gravity center -extent 300x300 -quality 100 +profile "*" cropSize.jpg_300x300.jpg
if (file_exists(ngx.var.request_filepath)) then
local cmd = gm_path .. ‘ convert -auto-orient -strip ‘ .. ngx.var.request_filepath
cmd = cmd .. " -thumbnail " .. ngx.var.img_width .. "x" .. ngx.var.img_height .. "^"
cmd = cmd .. " -gravity center -extent " .. ngx.var.img_width .. "x" .. ngx.var.img_height
-- 由于压缩后比较模糊,默认图片质量为100,请根据自己情况修改quality
cmd = cmd .. " -quality " .. ngx.var.img_fill
cmd = cmd .. " +profile "*" " .. ngx.var.img_file;
-- ngx.log(ngx.ERR, cmd);
os.execute(cmd);
ngx.exec(ngx.var.uri);
else
ngx.exit(ngx.HTTP_NOT_FOUND);
end
#####################################################################################################
创建image.conf
touch /usr/local/nginx/conf/image.conf
vi /usr/local/nginx/conf/image.conf
###########################################################################################
location ~ .*.(gif|jpg|jpeg|png|bmp|swf)$
{
expires 30d;
}
###########################################################################################
创建js.conf
touch /usr/local/nginx/conf/js.conf
vi /usr/local/nginx/conf/js.conf
###########################################################################################
location ~ .*.(js|css)?$
{
expires 1d;
}
###########################################################################################
创建nginxcrop.conf
vi /usr/local/nginx/conf/nginxcrop.conf
###########################################################################################
location /lua1 {
default_type ‘text/plain‘;
content_by_lua ‘ngx.say("hello, lua")‘;
}
set $img_original_root $upload_path;# original root;
set $img_thumbnail_root $upload_path/cache/thumb;
set $img_file $img_thumbnail_root$uri;
# like: /xx/xx/xx.jpg_100x100.jpg
location ~* ^(.+.(jpg|jpeg|gif|png))_+w(d+)+h(d+)+f(d+)+.(jpg|jpeg|gif|png)$ {
root $img_thumbnail_root; # root path for croped img
if (!-f $img_file) { # if file not exists
add_header X-Powered-By ‘Nginx+Lua+GraphicsMagick By Yanue‘; # header for test
add_header file-path $request_filename; # header for test
set $request_filepath $img_original_root$1; # origin_img file path
set $img_width $3; # img width
set $img_height $4; # height
set $img_fill $5; # height
set $img_ext $2; # file ext
content_by_lua_file lua/cropSize.lua; # load lua
}
}
###########################################################################################
创建vhosts/a.conf
mkdir /usr/local/nginx/conf/vhosts
vi /usr/local/nginx/conf/vhosts/a.conf
###########################################################################################
server
{
listen 80;
charset utf-8;
server_name 192.168.1.50;
index index.html index.htm index.php;
root /data/www/blog;
#设置图片路径 建议与root相同
set $upload_path /data/www/blog;
#limit_conn crawler 20;
include image.conf;
include js.conf;
include nginxcrop.conf;
log_format access ‘$remote_addr - $remote_user [$time_local] "$request" ‘ ‘$status $body_bytes_sent "$http_referer" ‘ ‘"$http_user_agent" $http_x_forwarded_for‘;
access_log /data/logs/access.log access;
}
###########################################################################################
最后启动nginx
/usr/local/nginx/sbin/nginx
测试：
真实图片地址：http://192.168.0.25/images/xxx/xxx/a.jpg
访问裁剪地址：http://192.168.0.25/images/xxx/xxx/a.jpg_w200h150f70.jpg
原文：https://www.cnblogs.com/cnsong/p/9093785.html
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