1-使用 koa 搭建服务器

var koa=require('koa')
  var app=new koa()
  app.use(async(ctx)=>{
    ctx.body='koa'
  })
  app.listen(3000,()=>{
    console.log('服务器已启动,端口正在监听...')
  })

2-如何配置 koa 路由

var koa=require('koa')
  var app=new koa()
  var Router=require('koa-router')
  var router=Router()
  router.use('/',(ctx)=>{
    ctx.body='koa'
  })
  app.use(router.routes())
  .use(router.allowedMethods())
  app.listen(3000,()=>{
    console.log('服务器已启动,端口正在监听...')
  })

3-静态资源如何获取

var app=new koa()
  var Router=require('koa-router')
  var router=Router()
  var path=require('path')
  var static=require('koa-static')
  app.use(static(path.join(__dirname,'public')))
  router.use('/',(ctx)=>{
    ctx.body='koa'
  })
  app.use(router.routes())
  .use(router.allowedMethods())
  app.listen(3000,()=>{
    console.log('服务器已启动,端口正在监听...')
  })

4-koa 如何使用模板引擎

var app=new koa()
  var Router=require('koa-router')
  var router=Router()
  var path=require('path')
  var static=require('koa-static')
  app.use(static(path.join(__dirname,'public')))
  var render=require('koa-art-template')
  render('app',{
    root:path.join(__dirname,'views'),
    extname:'.html',
    debug:procress.env.NODE_ENV!=='productions'
  })
  router.use('/',async(ctx)=>{
    await ctx.render('apps',{
      name:'张三'
    })
  })
  app.use(router.routes())
  .use(router.allowedMethods())
  app.listen(3000,()=>{
    console.log('服务器已启动,端口正在监听...')
  })

5-使用 koa 实现一个用户增删改查的案例

1. app.js

app.js为入口文件,功能是连接数据库,导入文件,引入koa组件,最后启动服务。

'use strict';
 
const fs = require('fs');
const path = require('path');
const mongoose = require('mongoose');
 
const db = 'mongodb://localhost/test';
 
/* 连接数据库 */
mongoose.Promise = require('bluebird');
mongoose.connect(db, {useMongoClient: true});
 
/**
 * 获取数据库表对应的js对象所在的路径
 * @type {[type]}
 */
const models_path = path.join(__dirname, '/app/models');
 
/**
 * 已递归的形式,读取models文件夹下的js模型文件,并require
 * @param {[type]} modelPath [description]
 * @return {[type]}   [description]
 */
let walk = function (modelPath) {
 fs.readdirSync(modelPath).forEach(function (file) {
  let filePath = path.join(modelPath, '/' + file)
  let stat = fs.statSync(filePath)
 
  if (stat.isFile()) {
   if (/(.*)\.(js|coffee)/.test(file)) {
    require(filePath)
   }
  }
  else if (stat.isDirectory()) {
   walk(filePath)
  }
 })
};
walk(models_path);
 
require('babel-register');
const Koa = require('koa');
const logger = require('koa-logger');
const session = require('koa-session');
const bodyParser = require('koa-bodyparser');
const app = new Koa();
 
app.use(logger());
app.use(session(app));
app.use(bodyParser());
 
 
/**
 * 使用路由转发请求
 * @type {[type]}
 */
const router = require('./config/router')();
 
app.use(router.routes());
app.use(router.allowedMethods());
 
app.listen(3000);
console.log('app started at port 3000...');

2. 路由配置

路由配置在config/router.js中进行。

const Router = require('koa-router');
const User = require('../app/controllers/user');
 
module.exports = function () {
 let router = new Router({
  prefix: '/api'
 });
 
 router.post('/test/user/users', User.users);
 router.post('/test/user/user', User.user);
 router.post('/test/user/add', User.addUser);
 router.post('/test/user/delete', User.deleteUser);
 return router
};

post方法第一参数为路由地址,第二参数为路由地址对应的方法。 

3. 表结构定义

表结构定义在app/models/user.js中。

let mongoose = require('mongoose');
let Schema = mongoose.Schema;
 
// 定义表结构
let UserSchema = new Schema({
 name: {
  type: String,
  required: true
 },
 sex: String,
 area: String,
 always: Boolean,
 relationship: Array,
 mobile: String,
 phone: String,
 desc: String,
 id: String
});
 
// 参数User 数据库中的集合名称, 不存在会创建.
let User = mongoose.model('User', UserSchema);
 
module.exports = User;

4. 工具方法

一些增删改查的工具方法放在app/dbhelp/userHelp.js中

'use strict';
 
let mongoose = require('mongoose');
let User = mongoose.model('User');
 
/* 查找用户 */
exports.findAllUsers = async () => {
 let query = User.find();
 let res = [];
 await query.exec(function (err, users) {
  if (err) {
   res = [];
  } else {
   res = users;
  }
 });
 return res
};
 
/* 查找特定用户 */
exports.findFilterUsers = async (params) => {
 let nameReg = new RegExp(params.name, 'i');
 let query = User.find({
  name: {
   $regex: nameReg
  }
 });
 let res = [];
 await query.exec(function (err, users) {
  if (err) {
   res = []
  } else {
   res = users;
  }
 });
 return res
};
 
/* 查找单个用户 */
exports.findUser = async (params) => {
 let query = User.find({
  id: params.id
 });
 let res = {};
 await query.exec(function (err, tUser) {
  if (err) {
   res = '没有该用户';
  } else {
   res = tUser[0];
  }
 });
 return res
};
 
/* 新增用户 */
exports.addUser = async (user) => {
 user = await user.save();
 return user
};
 
/* 编辑用户 */
exports.updateUser = async (user) => {
 user = await User.update({id: user.id}, {
  $set: {
   name: user.name,
   sex: user.sex,
   area: user.area,
   always: user.always,
   relationship: user.relationship,
   phone: user.phone,
   mobile: user.mobile,
   desc: user.desc
  }
 });
 return user
};
 
/* 删除用户 */
exports.deleteUser = async ({id}) => {
 let flag = false;
 console.log('flag==========>' + flag);
 await User.remove({id}, function (err) {
  if (err) {
   flag = false
  } else {
   flag = true
  }
 
 });
 console.log('flag=====await=====>' + flag);
 return flag
};

 

5. 路由配置中对应的方法

路由配置中对应的方法在app/controller/user.js中。

'use strict';
 
let xss = require('xss');
let mongoose = require('mongoose');
let User = mongoose.model('User');
let uuid = require('uuid');
import userHelper from '../dbhelper/userHelper.js'
 
/* 多用户 */
exports.users = async (ctx, next) => {
 let data;
 if (ctx.request.body) {
  data = await userHelper.findFilterUsers(ctx.request.body)
 } else {
  data = await userHelper.findAllUsers()
 }
 
 ctx.body = {
  success: true,
  data
 }
};
/* 单用户 */
exports.user = async (ctx, next) => {
 let data = await userHelper.findUser(ctx.request.body)
 
 ctx.body = {
  success: true,
  data
 }
};
/* 添加(更新)用户 */
exports.addUser = async (ctx, next) => {
 let newObj = ctx.request.body,
  user2;
 let id = newObj.id || uuid.v4();
 let user = new User({
  name: newObj.name,
  sex: newObj.sex,
  area: newObj.area,
  always: newObj.always,
  relationship: newObj.relationship,
  phone: newObj.phone,
  mobile: newObj.mobile,
  desc: newObj.desc,
  id: id
 });
 if (newObj.id) {
  user2 = await userHelper.updateUser(user);
 } else {
  user2 = await userHelper.addUser(user);
 }
 
 if (user2) {
  ctx.body = {
   success: true,
   data: user2
  }
 }
};
/* 删除用户 */
exports.deleteUser = async (ctx, next) => {
 let id = xss(ctx.request.body.id);
 let data = await userHelper.deleteUser({id});
 ctx.body = {
  success: true,
  data
 }
};