Add support for promises on req.login.

[dignifiedquire]

In response to #227 this uses promise.

Closes #225.

[topaxi]

Any news on this?

[listepo]

Ping

[jaredhanson]

On further consideration, I don't have any desire for Passport to support promise-style calling conventions. If need be, it is very easy to promisify req.login specifically in applications that need it.

There's too many opinions and options about how async functions should be called in JavaScript. If it's promises now, it'll be some ES* feature next. I'll follow the lead of Node core for what they expose on http.ServerResponse. If they do promises, Passport will, but not until then.

[callumacrae]

Promises are an ES6 feature… https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise

[listepo]

Express.js 5, Promises in all handlers expressjs/express#2259

[jaredhanson]

When Express 5 implements support for promises, I'll follow suit for Passport's middleware. Additional calling styles to http.ServerRequest will follow what Node core does with their API.

[Nicholaiii]

expressjs/express#2237

[nhooey]

@jaredhanson How can you promisify req.logIn globally?

I have successfully promisified req.logIn in each function that uses it inside an Express.js app, but haven't been able to promisify it globally:

const Promise = require('bluebird');

exports.whatever = async (req, res, next) => {
    req.login = Promise.promisify(req.logIn);

    // ... snip ...

    try {
        await req.logIn(user);
    } catch (e) {
        console.log(`Error logging in user: ${user.id}: ${e}`);
    }
}

Promisifying passport.authenticate emits this error:

TypeError: app.use() requires middleware functions

At this line in app.js:

app.use(passport.session());

[nhooey]

See issue #536 for adding promise support now that a lot of time has passed since this issue was created.