What is "done" callback function in Passport Strategy Configure "use" function
done
is a method called internally by the strategy implementation.
Then it navigates you, as you can see, to one of the success
/ error
/ fail
methods (again, by the implementation. there are more options).
Each of these options may calls to the next
, where in your snippet code is the following:
function(req, res) {
res.redirect('/');
});
When success
is called, it can attach the user to the request or do other things, depending on your needs (it looks for the options
you pass to passport.authenticate
). If you want to determine when next
will be called, you should use custom callback
which gives you more flexibility.
I strongly recommend that you read the source.
Steve.NayLinAung
I am Android and Php (Laravel) developer with strong C# programming knowledge. Database and server hosting are also among my semi-expertise skills.
Updated on March 20, 2020Comments
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Steve.NayLinAung about 4 years
I'm an node.js and express.js noob. This question may seems silly but I'm really in confusion.
I'm trying to configure Local Strategry authentication by using passport. As shown in the official documentation, we can figure this Local Strategy by the following code,
passport.use(new LocalStrategy( function(username, password, done) { User.findOne({ username: username }, function (err, user) { if (err) { return done(err); } if (!user) { return done(null, false); } if (!user.verifyPassword(password)) { return done(null, false); } return done(null, user); }); } ));
My confusion is about the
done
callback function. When the official docs show this local strategy using as a middleware in the route handler, there is no need to pass the function parameter for thisdone
callback.app.post('/login', passport.authenticate('local'), function(req, res) { res.redirect('/'); });
So, isn't this
done
callback function will be null if we don't provide the function parameter? If not, what is thatdone
callback function and what processes will be happening in thisdone
callback function? -
Steve.NayLinAung over 8 yearsThanks for the answer. After few hours I asked this question, I gradually understand that "done" might be managed internally by passport. Now I clear when I see your answer.
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Internial over 6 yearspassportjs documentation needs major improvement