Lua 操作 MongoDB 数据库实例

最近有个工作是使用Nginx + Lua实现一个操作MongoDB数据库的API，主要实现其count和query功能。之前没有写过Lua，于是也就勉强着上手，在cloudwu的 lua-mongo 的基础上实现了操作MongoDB的API。

cloudwu的lua-mongo驱动实现了连接Mongo，进行find和findOne等基本操作的功能，所以在lua-mongo的基础上增加了count和query等方法。修改的具体内容如下：

1、API基于luajit-2.0开发，相当于lua 5.1，需要使用lua-compat-5.2兼容lua 5.2

2、使用ngx.socket.tcp替换mongo.socket模块

3、增加了count，query，auth等方法

修改之后的代码见： lua-mongo

具体的操作MongoDB的lua代码如下：

代码如下：

-- lua mongo test script

-- utils

function string:split(sep)

  local sep, fields = sep or ":", {}

  local pattern = string.format("([^%s]+)", sep)

  self:gsub(pattern, function(c) fields[#fields + 1] = c end)

  return fields

end

-- 常量

HOST = "127.0.0.1"

PORT = 27017

KEEPALIVE_TIMEOUT = 60000

KEEPALIVE_SIZE = 100

CONN_TIMEOUT = 3000

DB_USER = "user"

DB_PASSWD = "password"

DB_NAME = "blog"

DB_COLLECTION = "article"

-- 引用

mongo = require("mongo")

cjson = require("cjson.safe")

cbson = require("bson")

-- 状态

local status_msg = "error"

local status_code = 500

local message = "unknown error"

local mongo_query = {["category_id"] = {["$in"] = {1,2,3,4}}, ["status"] = {["$ne"] = 2}, ["create_time"] = {["$lte"] = 1427102260}}

local mongo_sort = {["create_time"] = 1}

local mongo_limit = 100

local mongo_skip = 0

local mongo_fields = { ["_id"] = false }

-- 涉及到时间的字段，需要使用bson转化一下

if mongo_query["create_time"] then

  local create_time = mongo_query["create_time"]

  local t = type(create_time)

  if t == "table" then

    for key, value in pairs(create_time) do

      mongo_query["create_time"][key] = cbson.date(value)

    end

  else

    mongo_query["create_time"] = cbson.date(create_time)

  end

end

local conn = mongo.client({ host = HOST, port = PORT })

conn:set_timeout(CONN_TIMEOUT)

local db = conn:getDB(DB_NAME)

local reused_times = conn:get_reused_times()

if reused_times == 0 then

  db:auth(DB_USER, DB_PASSWD)

end

local col = db:getCollection(DB_COLLECTION)

local result = {}

-- count

local count, err = col:count(mongo_query)

local ok, err = conn:set_keepalive(KEEPALIVE_TIMEOUT, KEEPALIVE_SIZE)

if count ~= nil then

  result = count

  status_code = 200

  status_msg = "ok"

  message = "success"

end

-- query

local bson_obj

if mongo_sort then

  bson_obj = cbson.encode_order("$query", mongo_query, "$orderby", mongo_sort)

else

  bson_obj = cbson.encode({ ["$query"] = mongo_query })

end

local results = col:query(bson_obj, mongo_fields, mongo_skip, mongo_limit)

local ok, err = conn:set_keepalive(KEEPALIVE_TIMEOUT, KEEPALIVE_SIZE)

if results then

  for _, object in pairs(results) do

    for key, value in pairs(object) do

      if value == cbson.null then

        object[key] = cjson.null

      else

        local type_name, value = cbson.type(value)

        object[key] = value

      end

    end

  end

  result = results

  status_code = 200

  status_msg = "ok"

  message = "success"

end

-- findOne

local results = col:findOne({["id"] = 14 })

local ok, err = conn:set_keepalive(KEEPALIVE_TIMEOUT, KEEPALIVE_SIZE)

if results then

  for key, value in pairs(results) do

    if value == cbson.null then

      results[key] = cjson.null

    else

      local type_name, value = cbson.type(value)

      results[key] = value

    end

  end

  result = results

  status_code = 200

  status_msg = "ok"

  message = "success"

end

ngx.status = status_code

json_out = cjson.encode({ status = status_msg, message = message, data = result })

ngx.header["Content-Length"] = json_out:len()

ngx.print(json_out)