message on failed login and flash

[karan]

So right now my strategy is this:

passport.use(new LocalStrategy({
    usernameField: 'username',
    passwordField: 'userpassword'
}, function(username, password, callback) {
        console.log('authenticating.. : ' + username)
        User.findOne({username: username}, function(err, user) {
            if (err) return callback(err);

            // make sure the user exists
            if (!user) {
                return callback(null, false, {message: 'Username not found'});
            }

            // test for a matching password
            user.comparePassword(password, function(err, isMatch) {
                if (err) return callback(err);

                // check if password was a match
                if (isMatch) {
                    return callback(null, user);
                }

                // password incorrect
                return callback(null, false, {message: 'Password not found'});
            });
        });
    }

And in my app.js:

app.post('/signin', passport.authenticate('local', {successRedirect: '/dashboard', 
                                                failureRedirect: '/signin', 
                                                failureFlash: true}));

In a case when user enters no credentials at all, or just one of username or password, he sees the flash message Missing Credentials. I'd like the user to see one of my messages in my strategy Username not found or Password not found.

How does one do it?

[defshift]

@karan It seems that this the default behavior for passport-local strategy:
https://github.com/jaredhanson/passport-local/blob/master/lib/passport-local/strategy.js#L75

Therefore you can fork this one and modify for your own needs.

[karan]

But that would make maintenance harder for me. I'll just use failureFlash: 'Invalid username or password.' until I find a better way.