nginx图片处理笔记（http-image-filter-module、lua）

实验环境：CentOS 6.10

目标：1.使用http-image-filter-module进行图片变换；2.使用lua进行格式转换；

1. 安装EPEL
   
   https://fedoraproject.org/wiki/EPEL

   yum install https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm
   # or RHEL/CentOS 7
   # yum install https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
   

2. 由于lua-nginx-module声称（2018-12-06）测试的最新nginx稳定版本是1.12.x(参考：https://github.com/openresty/lua-nginx-module#nginx-compatibility），所以选择安装nginx版本为1.13.6

   curl -O http://nginx.org/download/nginx-1.12.2.tar.gz
   yum install -y gcc g++ gcc-c++ zlib zlib-devel openssl openssl-devel pcre pcre-devel
   yum install -y nginx-1.12.2
   yum install -y libjpeg-turbo-devel libpng-devel freetype-devel libtiff-devel libXpm-devel libwebp-devel fontconfig-devel
   

3. libimagequant && libgd && add http-image-filter-module
   
   https://github.com/libgd/libgd
   
   https://github.com/ImageOptim/libimagequant

   cd libimagequant-2.12.2
   ./configure --prefix=/usr
   make libimagequant.so
   make install
   > install -d /usr/lib
   > install -d /usr/lib/pkgconfig
   > install -d /usr/include
   > install -m 644 libimagequant.a /usr/lib/libimagequant.a
   > install -m 644 libimagequant.so.0 /usr/lib/libimagequant.so.0
   > ln -sf libimagequant.so.0 /usr/lib/libimagequant.so
   > install -m 644 imagequant.pc /usr/lib/pkgconfig/imagequant.pc
   > install -m 644 libimagequant.h /usr/include/libimagequant.h
   #
   cd ../libgd-2.2.5
   ./configure --with-liq=/opt/src/libimagequant-2.12.2
   make
   make install
   gdlib-config --all
   > gdlib-config: warning: this script is deprecated; please use the pkg-config file instead.
   > GD library  2.2.5
   > includedir: /usr/local/include
   > cflags:     -I/usr/local/include
   > ldflags:
   > libs:       -lm   -lz    -lpng12    -lfreetype    -lfontconfig     -ljpeg   -limagequant -fopenmp  > -lXpm -lX11     -ltiff   -lwebp
   > libdir:     /usr/local/lib
   > features:   GD_GIF GD_GIFANIM GD_OPENPOLYGON GD_ZLIB GD_PNG GD_FREETYPE GD_FONTCONFIG GD_JPEG GD_LIQ GD_XPM GD_TIFF GD_WEBP
   ln -s /usr/local/lib/libgd.so.3.0.5 /usr/lib64/libgd.so
   ln -s /usr/local/lib/libgd.so.3.0.5 /usr/lib64/libgd.so.3
   ln -s /usr/lib/libimagequant.so.0 /usr/lib64/libimagequant.so.0
   #
   cd nginx-1.12.2
   # 已经安装 yum install -y nginx-1.12.2，所以通过nginx -V获取原编译参数，再加上--with-http_image_filter_module重新编译
   nginx -V
   ./configure --prefix=/etc/nginx --sbin-path=/usr/sbin/nginx --modules-path=/usr/lib64/nginx/modules --conf-path=/etc/nginx/nginx.conf --error-log-path=/var/log/nginx/error.log --http-log-path=/var/log/nginx/access.log --pid-path=/var/run/nginx.pid --lock-path=/var/run/nginx.lock --http-client-body-temp-path=/var/cache/nginx/client_temp --http-proxy-temp-path=/var/cache/nginx/proxy_temp --http-fastcgi-temp-path=/var/cache/nginx/fastcgi_temp --http-uwsgi-temp-path=/var/cache/nginx/uwsgi_temp --http-scgi-temp-path=/var/cache/nginx/scgi_temp --user=nginx --group=nginx --with-compat --with-file-aio --with-threads --with-http_addition_module --with-http_auth_request_module --with-http_dav_module --with-http_flv_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_mp4_module --with-http_random_index_module --with-http_realip_module --with-http_secure_link_module --with-http_slice_module --with-http_ssl_module --with-http_stub_status_module --with-http_sub_module --with-http_v2_module --with-mail --with-mail_ssl_module --with-stream --with-stream_realip_module --with-stream_ssl_module --with-stream_ssl_preread_module --with-cc-opt='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic -fPIC' --with-ld-opt='-Wl,-z,relro -Wl,-z,now -pie' --with-http_image_filter_module
   > ...
   > checking for GD library ... found
   > checking for GD WebP support ... found
   > ...
   make
   cd objs
   cp /usr/sbin/nginx /usr/sbin/nginx.old.20181206
   /cp nginx /usr/sbin/nginx -f
   nginx -V
   

4. 测试nginx

    location ~* ^/img/.*_(\d+)x(\d+)\.(jpg|JPG|gif|GIF|png|PNG)$ {
        set $img_width $1;
        set $img_height $2;
        rewrite ^(.*)_(\d+)x(\d+)\.(jpg|JPG|gif|GIF|png|PNG)$ $1.$4 break;
        image_filter resize $img_width $img_height;
        image_filter_buffer 10M;
    }
   

5. 测试image_filter是否支持webp

   yum install -y libwebp-tools
   cwebp xxx.jpg -o xxx.webp
   curl -I http://192.168.178.130/img/288822bcfbcbdea89eaa9b84cc42f562_500x500.webp
   

6. 测试image_filter + proxy_pass

   location ~* ^/oss/(.*)_(\d+)x(\d+)\.(jpg|JPG|jpeg|JPEG|gif|GIF|png|PNG|webp|WEBP)$ {
       set $img_width $2;
       set $img_height $3;
       image_filter resize $img_width $img_height;
       image_filter_buffer 10M;
       resolver 114.114.114.114;
       proxy_pass http://image-demo.oss-cn-hangzhou.aliyuncs.com/$1.$4;
       # 借用oss的示例图片 https://help.aliyun.com/document_detail/44688.html
   }
   

7. LUAJIT

   # http://luajit.org/download.html
   curl -O http://luajit.org/download/LuaJIT-2.0.5.tar.gz
   tar -zxvf LuaJIT-2.0.5.tar.gz
   cd LuaJIT-2.0.5
   make PREFIX=/usr/local/luajit
   make install PREFIX=/usr/local/luajit
   vi /etc/profile
   >> export LUAJIT_LIB=/usr/local/luajit/lib
   >> export LUAJIT_INC=/usr/local/luajit/include/luajit-2.0
   source /etc/profile
   

8. ngx_devel_kit (NDK) && lua-nginx-module

   # https://github.com/openresty/lua-nginx-module/releases
   tar -zxvf lua-nginx-module-0.10.13.tar.gz
   # https://github.com/simpl/ngx_devel_kit/releases
   tar -zxvf ngx_devel_kit-0.3.0.tar.gz
   

9. 编译安装nginx

   ./configure --prefix ...省略... --with-http_image_filter_module --add-module=/opt/src/ngx_devel_kit-0.3.0 --add-module=/opt/src/lua-nginx-module-0.10.13
   make
   cd objs
   cp /usr/sbin/nginx /usr/sbin/nginx.old.20181215
   /bin/cp nginx /usr/sbin/nginx -f
   ln -s /usr/local/luajit/lib/libluajit-5.1.so.2.0.5 /usr/lib64/libluajit-5.1.so.2
   service nginx restart
   # 验证Nginx是否链接了libluajit-5.1.so.2
   ldd /usr/sbin/nginx | grep lua
   

10. hello,lua

    location /lua_hello {
        default_type 'text/plain';
        content_by_lua 'ngx.say('hello,lua!')';
    }
    location /lua_hello2 {
        default_type 'text/plain';
            content_by_lua_block {
            ngx.say("hello,world!");
            ngx.log(ngx.ERR, "hello");
        }
    }
    

11. 用lua来做代理

    location ~* ^/lua_capture/(.*)_(\d+)x(\d+)\.(jpg|JPG|jpeg|JPEG|gif|GIF|png|PNG|webp|WEBP)$ {
        default_type 'text/plain';
        content_by_lua_block {
            local proxy_url = "/proxy/" .. ngx.var[1] .. "." .. ngx.var[4]
            ngx.log(ngx.ERR, proxy_url)
            local resp = ngx.location.capture(proxy_url, {
                method = ngx.HTTP_GET,
                args = {q="hello"}
            })
            if not resp then
                ngx.say("request error:", err);
                return
            end
            ngx.log(ngx.ERR, tostring(resp.status))
    
            ngx.status = resp.status
    
            for k, v in pairs(resp.header) do
                if k ~= "Transfer-Encoding" and k ~= "Connection" then
                    ngx.header[k] = v
                end
            end
    
            if resp.body then
                ngx.say(resp.body)
            end
        }
    }  
    
    location ~ ^/proxy/(.*)$ {
        # internal;
        resolver 114.114.114.114;
        proxy_pass http://image-demo.oss-cn-hangzhou.aliyuncs.com/$1;
    }
    

12. todo: 如何实现实时转webp呢？

参考：

1. nginx模块 ngx_http_image_filter_module
2. ngx.location.capture 只支持相对路径，不能用绝对路径
3. 利用 Aliyun OSS Nginx proxy module 实现OSS 图片处理回写功能
4. 大型网站高并发解决方案分析之图片服务器分离架构
5. WebP（整理），比较了WebP和PNG