kora 简单使用实现Api接口 以及mongodb简单使用

//api.js
const Koa = require('koa');
const router = require('koa-router')();  //路由
const bodyParser = require('koa-bodyparser'); //解析原始request请求
const fs  = require('fs');  //文件读取
const cors = require('koa2-cors'); //设置cors头
const app = new Koa;

/**
 * 数据库连接
 */
var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost:27017/admin', {'useNewUrlParser': true});
var db = mongoose.connection;
db.on('error', console.error.bind(console, 'connection error:'));
db.once('open', function() {
    console.log('数据库连接成功')

    /** 
     * Schema 用来定义存储在document 中的属性，并且赋予他们校验的规则，和默认值
    */
    var kittySchema = new mongoose.Schema({
        name: String
      });


      kittySchema.methods.speak = function () {
        var greeting = this.name
          ? "Meow name is " + this.name
          : "I don't have a name";
        console.log(greeting);
      }

      /** 
        * 定义模型
        */
      var Kitten = mongoose.model('Kitten', kittySchema);

      /** 
        * 模型实例
        */
      var silence = new Kitten({ name: 'Silence' });
      console.log(silence.name); // 'Silence'
      silence.save();  //插库

      var fluffy = new Kitten({ name: 'fluffy' });
      fluffy.save(function (err, fluffy) {
        if (err) return console.error(err);
        fluffy.speak();
      });

});


app.use(bodyParser()); 

app.use(cors({
    origin: function (ctx) {
        return '*'; 
    }
}));

let files = fs.readdirSync(__dirname + '/controllers');
let js_files = files.filter((f)=>{
    return f.endsWith('.js');
});

for( let f of js_files ){
    console.log(`process conteoller : ${f} ...`);
    let mapping  = require(__dirname + '/controllers/' + f );
    
    for ( let url in mapping ){
        if( url.startsWith('GET ')){
            //如果url类似'GET xxx'
            let path = url.substring(4);
            router.get(path,mapping[url]);
        }else if( url.startsWith('POST ') ){
            //如果url类似'POST xxx'
            let path = url.substring(5);
            console.log('请求方式是:',path);
            router.post(path,mapping[url]);
        }
    }

}

app.use(router.routes());

app.listen(8888);
console.log('app started at port 8888...');