将登录更改为注销

Question

I want to change login button to logout when ctx.session.userID have value, I try to use ejs engine, but it didn't work, is there any problem, or other better way. This is server.js:

const M = require('./model')
const Koa = require('koa')
var serve = require('koa-static')
const session = require('koa-session')
var KoaRouter = require('koa-router')
var koaLogger = require('koa-logger')
const koaBody = require('koa-body')
const views = require('koa-views')
var app = new Koa()
const router = new KoaRouter()
app.use(views('view', {map:{html:'ejs'}})) 
app.use(koaLogger())
app.use(koaBody())
app.use(router.routes())
app.use(serve(__dirname + '/public'));
app.keys = ['*@&))9kdjafda;983'] 
const CONFIG = { 
  key: 'd**@&(_034k3q3&@^(!$!',
  maxAge: 86400000
}
app.use(session(CONFIG, app)) 
router
.get('/', async (ctx) => {
    let title = 'ejs test'
    let userid = ctx.session.userID
    await ctx.render('index',{
        title, userid
    })
})

.post('/login', login)

.get('/error', async (ctx)=> {
    await ctx.render('error',{})
})

async function login(ctx){
    let {id, password} = ctx.request.body
    console.log("test:",id,password)
    if ( await M.get(id,password) != null){
        ctx.session.userID = id
        ctx.redirect('/')
        console.log('login success')
    }
    else {
        ctx.redirect('/error')
    }
}

And this is a part of index.html:

            <% if (userid == null){ %>
            <a href="/login">Login</a>   
            <% } else { %>
            <a href="/logout">Logout</a>
            <% } %>

Answer 1

In your get('/') route function, you are not using the same session variable you set in your login() function. Change the get('/') function to let userid = ctx.session.userID with the capital ID and log it to the console before sending to the template to make sure the variable is indeed set correctly.

Answer 2

I am assuming that you are using session in this application. In the index.html you can check whether the status is logged in or not by using following Ejs code:

 <li id="login"> <a href="<%= logStatus==='out'?'login':'logout'%>"> <%= logStatus==='out'?'LOGIN':'LOGOUT'%> </a> </li>

After this you can pass the status of login and logout through the Node.js, for each res.render() function you use in the Node.js code by following:

 res.render("[your route name]", { logStatus:`${req.session.user? 'in':'out'}` });

for Example:

 app.get("/upload", checkSignIn, (req, res) => { res.render("upload", { logStatus:`${req.session.user? 'in':'out'}` }); });

Note: Always pass the logStatus with every render to avoid error and you don't need to change anything in that, it will automatically check the status from session and send status.

If you have different name for session, then change it in the req.session.[name of the session]. for Example: if I have a session name like autoTocken then it will be like:

 app.get("/upload", checkSignIn, (req, res) => { res.render("upload", { logStatus:`${req.session.autoTocken ? 'in':'out'}` }); });