OpenResty+lua+GraphicsMagick生成缩略图

tar zxvf GraphicsMagick-1.3.19.tar.gz
cd GraphicsMagick-1.3.19
make
make install

yum install -y ghostscript

location /down/PersonImg {
            set $image_root /usr/local/openresty/nginx/html;
            set $file "$image_root$uri";
            rewrite_by_lua '
                local index = string.find(ngx.var.uri, "([0-9]+)x([0-9]+)");
                local originalUri = string.sub(ngx.var.uri, 0, index-2);
                local area = string.sub(ngx.var.uri, index);
                index = string.find(area, "([.])");
                area = string.sub(area, 0, index-1);
                local image_sizes = {"140x140", "800x800", "90x90"};

                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 = "/usr/local/GraphicsMagick/bin/gm convert " .. ngx.var.image_root ..  originalUri  .. " -thumbnail " .. area .. " -gravity center -extent " .. area .. " " .. ngx.var.file;
                    os.execute(command);
                else
                    ngx.exit(401)
                end
            ';
            alias /usr/local/openresty/nginx/html/down/PersonImg/;

        }

/usr/local/GraphicsMagick/bin/gm convert /usr/local/openresty/nginx/html/down/PersonImg/3AFAE457-FDC8-27D3-E2B5-6C10A145A3A6.jpg -font ArialBold -pointsize 45 -fill red -draw "text 10,10 dsideal" /usr/local/openresty/nginx/html/down/PersonImg/3AFAE457-FDC8-27D3-E2B5-6C10A145A3A61111.jpg