PostgreSQL Node.js实现函数计算方法示例

前言

由于工作需要，设计到了阿里云的弹性计算，这里便记录下来

技术栈

• node.js
• postgresql
• nodemailer

controller +  services

编写postgresql lib

不管异常还是正常都返回resolve，在resolve中处理结果，通过success字段去处理

const { pool } = require('pg');
const config = require('../config/default.js');
const {
 database: {
 host,
 port,
 database,
 username,
 password,
 },
} = config;
const pool = new pool({
 port: port,
 host: host,
 user: username,
 password: password,
 database: database,
});
/**
 * 
 * @param sql 接收的sql语句
 * @param {array} values sql语句参数
 * @return { object } { success: boolean, err || data }
 */
const query = async function( sql = 'select now()', values = []) {
 return new promise(resolve => {
 pool.connect((err, client, release) => {
 if (err) {
 return console.error('error acquiring client', err.stack)
 }
 const params = array.isarray(values) ? [...values] : [values];
 client.query(sql, params, (error, result) => {
 release();
 if (error) {
  console.error('error executing query', error.stack);
  resolve({
  success: false,
  error,
  });
 }
 resolve({
  success: true,
  data: result.rows,
 });
 });
 });
 });
}

module.exports = {
 query,
}

config配置文件如下

const config = {
 // 数据库配置
 database: {
 database: 'databasename',
 username: 'root',
 password: '123456',
 port: '3433',
 host: 'localhost',
 },
};

module.exports = config;

controller

basecontroller

首先编写一个基类，用于封装一些通用的方法

const pool = require('../lib/postgre'); // 导入封装好的mysql库
const { query } = pool; // 导入query方法
class basecontroller {
 constructor() {
 }
 // 查询表内所有数据（非删除）
 async list() {
 const sql = `select * from ${this.table}`;
 return await query(sql);
 }
 async excute(sql, vals = []) {
 // 执行方法
 return await query(sql, vals);
 }
 // log 方法
 log({func, err}) {
 console.log(`excute function[${func}] occured error : ${err.message || err}`);
 }
}

module.exports = basecontroller;

inquerycontroller

具体的业务逻辑controller类

const basecontroller = require('./basecontroller'); // 获得基类
// 继承基类
class inquerycontroller extends basecontroller {
 constructor() {
 super();
 this.table = 'data_table'; // 赋值table
 }
 // 可以重写基类的方法，如果有业务需要
 async list() {
 const sql = `select * from ${this.table} order by created_at desc `;
 return await this.excute(sql);
 }
 async getunsendcustomer(vals) {
 const sql = `select * from ${this.table} where created_at > $1 order by created_at desc`;
 // 统一在基类调用sql参数
 return await this.excute(sql, vals);
 }
 
}
module.exports = inquerycontroller;

service

baseservice

统一封装的方法，基类

// 需要绑定this的方法
const funcs = [
 'list',
]
class baseservice {
 constructor() {
 this.controller = null;
 // 循环遍历绑定this, 在koa绑定route的时可用到
 funcs.foreach(item => {
  this[item] = this[item].bind(this)
 });
 }

 // 查询方法
 async list(ctx) {
 if (!ctx) {
  return await this.controller.list();
 }
 // controller返回的是一个对象，success(成功为true， 失败为false), data(成功则有此数据), err(失败则有此对象)
 const { success: flag, data, error } = await this.controller.list();
 if (flag) {
  // success
  ctx.body = {
  data,
  code: 200,
  }
 } else {
  // failed
  ctx.body = {
  code: 500,
  error,
  };
 }
 }
}

module.exports = baseservice

inqueryservice

具体的业务逻辑

// 导入基类
const baseservice = require('./baseservice');
// 导入对应的controller
const controller = require('../controller/inquerycontroller');
// 获取mailsender service
const mailservice = require('./mailsender');
const helper = require('../util/helper');

const funcs = [
 'unsenduser',
];
// 生成一次controller
const controller = new controller();
class inqueryservice extends baseservice {
 constructor() {
 super()
 // 绑定对应的controller
 this.controller = controller;
 funcs.foreach(item => {
  this[item] = this[item].bind(this);
 });
 }
 getmailopts(i) {
 // you can use the data from database to combine the message
 const message = 'hello world!';
 return return {
  message,
  // 可以从配置文件读取或者oss
  to: '[e-mail]',
  subject: 'hello world',
 };
 }
 
 async unsenduser() {
 const list = await this.controller.list();
 if (list.length > 0) {
  const mailer = new mailservice();
  const errorlist = [];
  iteratelist.foreach(async i => {
  const maileroption = this.getmailopts(i);
  const { success, ...rest } = await mailer.sendtoauitadmin(maileroption);
  if (!success) {
   errorlist.push(rest);
  }
  });
  const lastesttime = iteratelist[0].created_at;
  if (errorlist.length === 0) {
  return {
   code: 200,
   message: 'success',
  };
  }
 } else {
  return {
  code: 204,
  message: 'no user found',
  };
 }
 }
}
module.exports = new inqueryservice();

index.js

函数计算的逻辑

const inqueryservice = require('./services/inqueryservice'); 
exports.handler = async function(event, context, callback) {
 const result = await inqueryservice.unsenduser();
 callback(null, result);
};

总结

以上就是这篇文章的全部内容了，希望本文的内容对大家的学习或者工作具有一定的参考学习价值，如果有疑问大家可以留言交流，谢谢大家对的支持。