1. lua模块demo（redis，http，mysql，cjson，本地缓存）

1.1. 配置

1. 在nginx.conf中设置lua_shared_dict my_cache 128m; 开启nginx本地缓存，放到http{} 层
2. location配置

location /redis-get{

    resolver 8.8.8.8;

    default_type text/html;

    content_by_lua_file /usr/local/openresty/lua/redis-get.lua;

}

1. 这里推荐个工具，使用notepad++，下载个插件NppFtp，效果如下图，可以直接对liunx上的文件进行编辑保存

1.2. http

1. 远程调用可以使用该模块 https://github.com/ledgetech/lua-resty-http
2. 把lib包里的两个文件复制到 /usr/local/openresty/lualib/resty
3. 通过require("resty.http") 调用

1.3. mysql

1. 连接工具

local connectMysqlUtil = {}

local mysql = require "resty.mysql"

-- connect to mysql;

function connectMysqlUtil.connect()

    local db, err = mysql:new()

    if not db then

        return false

    end

    db:set_timeout(1000)

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

        host = "127.0.0.1",

        port = 8083,

        database = "test",

        user = "dev",

        password = "1234",

        max_packet_size = 1024 * 1024 }

    if not ok then

		ngx.say("connect mysql failed")

        return false

    end

    return db

end

return connectMysqlUtil

参考 https://www.cnblogs.com/zhuzi91/p/7879956.html

1.4. string工具

local stringEx = {}

function stringEx.ToStringEx(value)

    if type(value)=='table' then

       return stringEx.TableToStr(value)

    elseif type(value)=='string' then

        return "\'"..value.."\'"

    else

       return tostring(value)

    end

end

function stringEx.TableToStr(t)

    if t == nil then return "" end

    local retstr= "{"

    local i = 1

    for key,value in pairs(t) do

        local signal = ","

        if i==1 then

          signal = ""

        end

        if key == i then

            retstr = retstr..signal..stringEx.ToStringEx(value)

        else

            if type(key)=='number' or type(key) == 'string' then

                retstr = retstr..signal..'['..stringEx.ToStringEx(key).."]="..stringEx.ToStringEx(value)

            else

                if type(key)=='userdata' then

                    retstr = retstr..signal.."*s"..stringEx.TableToStr(getmetatable(key)).."*e".."="..stringEx.ToStringEx(value)

                else

                    retstr = retstr..signal..key.."="..stringEx.ToStringEx(value)

                end

            end

        end

        i = i+1

    end

     retstr = retstr.."}"

     return retstr

end

function stringEx.StrToTable(str)

    if str == nil or type(str) ~= "string" then

        return

    end

    return loadstring("return " .. str)()

end

return stringEx

1.5. 整合redis+本地缓存

-- 自定义的字符串转换工具

local stringEx = require("stringExt")

-- 本地缓存

local local_cache = ngx.shared.my_cache

-- redis连接池，设置连接空闲时间

local function close_redis(red)

	if not red then

		return

	end

	local pool_max_idle_time = 10000

	local pool_size = 100

	local ok,err = red:set_keepalive(pool_max_idle_time,pool_size)

	if not ok then

		ngx.say("set keepalive fail ",err)

	end

end

-- 读redis缓存

local function read_redis(key)

	local redis = require("resty.redis")

	local red = redis.new();

	local ok,err = red:connect("127.0.0.1",8084)

	if not ok then

		ngx.say("connect fail ",err)

		return close_redis(red)

	end

	red:set_timeout(1000)

	local count,err = red:get_reused_times()

	if 0==count then

		ok,err = red:auth("123456")

		if not ok then

			ngx.say("auth fail ",err)

			return close_redis(red)

		end

	elseif err then

		ngx.say("fail to get reused times")

		return close_redis(red)

	end

	local res,err = red:get(key)

	if not res then

		ngx.say("get msg fail ",err)

		return close_redis(red)

	elseif res then

		ngx.say(" set expire 10000 ")

		red:expire(key,10)

	end

	local_cache:set(key,res,5)

	ngx.say("read from redis ")

	ngx.say(res)

	close_redis(red)

end

-- http请求参数

local args = ngx.req.get_uri_args()

local key = args["key"]

if not key then

	ngx.say("key must be exist")

	return

end

local keyCache = local_cache:get(key)

if not keyCache then

	local res = read_redis(key)

	if not res then

		ngx.say("redis is null")

	end

else

	ngx.say("read from localCache ")

	ngx.say(keyCache)

end

-- http调用工具，需要额外下载，地址：https://github.com/ledgetech/lua-resty-http 说明：https://blog.csdn.net/xiejunna/article/details/53445342

local http = require("resty.http")

local httpc = http.new();

if not httpc then

	ngx.say("\n\r httpc new fail")

end

httpc:set_timeout(8000)

-- keepalive参数不写可能导致报错

local res,err = httpc:request_uri("http://www.xxx.com",{

	method="POST",

	path="/xxx/rpc.api",

	body = 'a=1&b=2',

	headers = {

          ["Content-Type"] = "application/x-www-form-urlencoded",

        },

	keepalive_timeout = 60,

	keepalive_pool = 10

})

if not res then

	ngx.say("httpc call fail ")

	return

end

local cjson = require("cjson")

local json = cjson.new()

if not json then

	ngx.say("json is null")

	return

end

-- 测试调用结果

-- ngx.say(stringEx.TableToStr(res))

-- ngx.say(stringEx.ToStringEx(json.decode(res["body"])))

-- ngx.say(type(json.decode(res["body"])))

-- ngx.say(stringEx.ToStringEx(json.decode(res["body"])["header"]["request_seq"]))

-- ngx.say(type(json.decode(res["body"])["header"]))

-- ngx.say(type(json.decode(res["body"])["header"]["request_seq"]))

local connectMysqlUtil = require("connectMysqlUtil")

local db = connectMysqlUtil.connect()

if not db then

	ngx.exit(ngx.HTTP_INTERNAL_SERVER_ERROR)

	return

end

local res,err,errcode,sqlstate = db:query("select * from t_uls_order_info where order_id='20190119232946000023'",10)

if not res then

	ngx.say("bad request: ",err,":",errcode,": ",sqlstate,".")

	return

end

ngx.say("result:",json.encode(res))

1.6. 总结

1. 本文记录了对http，mysql，redis，nginx本地缓存的基本使用方式，后续需要使用到该模块的需求可以直接参考修改本示例代码
2. 对于实际的互联网需求，这里可以想象个基于这些模块的需求，优先读取ngnix本地缓存，过期时间较短，其次读取redis缓存，减少redis压力，进一步减少mysql读取压力