ctx.cookies.set(name,value,[options]);

ctx.cookies.get('name');

//设置中文Cookie
router.get('/',async (ctx)=>{

    var userinfo=new Buffer('张三').toString('base64');
     ctx.cookies.set('userinfo',userinfo,{
        maxAge:60*1000*60
     });
})
//获取中文Cookie
router.get('/news',async (ctx)=>{

    var data=ctx.cookies.get('userinfo');
    var userinfo=new Buffer(data, 'base64').toString();

    console.log(userinfo);
})

cnpm install koa-session --save

const session = require('koa-session');

app.keys = ['some secret hurr'];
const CONFIG = {
key: 'koa:sess', //cookie key (default is koa:sess)
maxAge: 86400000, // cookie 的过期时间 maxAge in ms (default is 1 days)
overwrite: true, //是否可以 overwrite (默认 default true)
httpOnly: true, //cookie 是否只有服务器端可以访问 httpOnly or not (default true)
signed: true, //签名默认 true
rolling: false, //在每次请求时强行设置 cookie，这将重置 cookie 过期时间（默认：false）
renew: false, //(boolean) renew session when session is nearly expired,
};
app.use(session(CONFIG, app));

//设置值
 ctx.session.username = "张三";
//获取值
 ctx.session.username