脚手架：koa-generator，使用koa编写一些实例
koa最大的便利就是使用 async、await 让数据库查询变成同步
- koa使用async、await
- koa连接mysql数据库
- koa生成excel表格接口
- koa封装操作数据库接口
- koa编写中奖接口实例
// 设置koa跨域
app.use(async (ctx, next) => {
ctx.set('Access-Control-Allow-Origin', '*');
await next();
}); let qry = 'select name, phone, prize, DATE_FORMAT(addtime, "%Y-%m-%d %H:%i:%S") as addtime from awardLog order by addtime desc';
let _data = await DB.query(qry); //查询数据库
let rows = [];
for (let i in _data) {
rows[i] = [
_data[i].name,
_data[i].phone,
_data[i].prize,
_data[i].addtime,
]
};
conf.rows = rows;
var result = nodeExcel.execute(conf);
let data = Buffer.from(result, 'binary');
let name = encodeURI('测试表');
ctx.set('Content-Type', 'application/vnd.openxmlformats;charset=utf-8');
ctx.set("Content-Disposition", "attachment; filename=" + name + ".xlsx");
console.log("处理数据：", data);
ctx.body = data;let currTime = Math.ceil(Math.random() * 100);
// 一等奖概率 5%， 二等奖 20%， 三等奖30%， 安慰奖 45%
if (currTime >= 0 && currTime <= 1) {
let qry1 = `select * from awardLog where awardId = 1 and phone = ${phone}`;
result1 = await DB.query(qry1); //如果一等奖抽过了，就不能再抽一等奖了
if (result1.length > 0) {
currTime = Math.ceil(Math.random() * 100) + 10;
} else {
succBack.data = {
awardId: 1
}
awardId = 1;
}
}
// 二等奖
if (currTime > 1 && currTime <= 10) {
succBack.data = {
awardId: 2
}
awardId = 2;
}
// 三等奖
if (currTime >10 && currTime <= 40) {
succBack.data = {
awardId: 3
}
awardId = 3;
// ctx.body = succBack;
}
// 安慰奖
if (currTime > 40) {
succBack.data = {
awardId: 4
}
awardId = 4;
// ctx.body = succBack;
}