简介

OpenResty 能够使用Lua语言快速构造出足以胜任10K+并发连接响应的超高性能web应用, 构建web应用不可避免地会访问数据库，本篇介绍openresty如何访问mysql。

本教程适用于CentOS 6.x版本。

在使用Openresty访问mysql之前，您需要先建立Openresty工作环境，可以参考在CentOS 6上搭建openresty环境，参考在Centos 6上建立lnmp建立mysql环境。

建立mysql表

在mysql数据库中建立openresty数据库和user表，其中已设置mysql访问密码为'root':

$sudo mysql -uroot -proot

mysql> CREATE DATABASE IF NOT EXISTS openresty DEFAULT CHARSET utf8 COLLATE utf8_general_ci;

Query OK, 1 row affected (0.00 sec)

mysql> use openresty

Database changed

mysql> create table user ( id int(10) not null auto_increment, name varchar(80) not null default '', email varchar(80) not null default '', primary key(id)) DEFAULT CHARSET=UTF8;

Query OK, 0 rows affected (0.00 sec)

nginx的配置如下：

http {

init_by_lua '

mysql = require "resty.mysql"

cjson = require "cjson"

';

server {

listen 80;

server_name localhost;

location /insert {

content_by_lua_file conf/user.lua;

}

location /delete {

content_by_lua_file conf/user.lua;

}

location /query {

content_by_lua_file conf/user.lua;

}

}

}

lua脚本文件user.lua如下：

function connect_mysql()

local db, err = mysql:new()

if not db then

ngx.log(ngx.ERR, "failed to instantiate mysql: "..err)

return

end

db:set_timeout(1000) -- 1 sec

local ok, err, errno, sqlstate = db:connect{

host = '127.0.0.1',

port = 3306,

database = 'openresty',

user = 'root',

password = 'root',

max_packet_size = 1024 * 1024,

pool = "openrestypool" }

if not ok then

ngx.log(ngx.ERR, "failed to connect: ", err, errno, sqlstate)

return

end

return db

end

function keepalive(mydb)

if httpdnsdb~=nil then

local ok, err = mydb:set_keepalive(0, 1000)

if not ok then

ngx.log(ngx.ERR, "failed to set keepalive: ", err)

return

end

end

end

function myquery(querystring)

mydb=connect_mysql()

if not mydb then

ngx.say("mydb is nil.")

return;

end

local res, err, errno, sqlstate = mydb:query(querystring)

if err then

ngx.say('"error":'..err)

elseif res then

ngx.say(cjson.encode(res))

end

keepalive(mydb)

end

ngx.req.read_body()

args=ngx.req.get_uri_args()

if (ngx.var.uri == '/insert') then

ngx.req.set_header('Content-Type', 'text/html;charset=utf8');

local queryString="INSERT INTO user(name, email) VALUES('".. args.name .. "','" .. args.email .. "')"

myquery(queryString)

elseif (ngx.var.uri == '/delete') then

ngx.req.set_header('Content-Type', 'text/html;charset=utf8');

local queryString= "delete from user WHERE name='"..args.name.."'"

myquery(queryString)

elseif (ngx.var.uri == '/query') then

ngx.req.set_header('Content-Type', 'text/html;charset=utf8');

local queryString= "select * from user WHERE name='"..args.name.."'"

myquery(queryString)

end

启动nginx，并使用curl测试：

$ sudo /usr/local/openresty/nginx/sbin/nginx -c /usr/local/openresty/nginx/conf/nginx.conf

$ curl "http://127.0.0.1/insert?name=abc&email=abc@163.com"

{"insert_id":7,"server_status":2,"warning_count":0,"affected_rows":1}

$ curl "http://127.0.0.1/query?name=abc"

[{"email":"abc@163.com","name":"abc","id":7}]

$ curl "http://127.0.0.1/delete?name=abc"

{"insert_id":0,"server_status":34,"warning_count":0,"affected_rows":1}

$ curl "http://127.0.0.1/query?name=abc"

{}

总结

使用美团云主机，可以很方便地使用yum源获取软件，建立属于自己的openresty和lua环境，访问mysql，快速实现自己10k+的超高性能WEB应用。