AJAX response error: net::ERR_EMPTY_RESPONSE

Question

CODE:

FRONT-END

$(document).ready(function(){
        $('.delete-post').on('click', function(){
            var id = $(this).data('id');
            var section = $(this).data('section');
            var url = '/users/delete/'+id;
            if(confirm("Delete Post ?")){
                $.ajax({
                    url: url,
                    type:'DELETE',
                    success: function(result){
                        console.log('Deleting post...');
                        window.location.href='/users/profile';
                    },
                    error: function(err){
                        console.log(err);
                    }
                });
            }
        });
    });

BACK-END:

router.delete('/delete/:id', function(req, res, next) {

    var id = req.params.id;
    var section = req.params.section;

    var image = "";
    var author = "";

    var postRef = firebase.database().ref("posts/"+section+"/"+id);
    var userRef = firebase.database().ref("users/posts/"+id);
    var likesRef = firebase.database().ref("users/likes/"+id);
    var hotRef = firebase.database().ref("hot/"+section+"/"+id);

    postRef.once('value', function(snapshot){
        image = snapshot.image;
        author = snapshot.author;

        if (firebase.auth().currentUser.uid.toString() == author) {
            var file = bucket.file(image);

            file.delete(function (err, apiResponse) {
                  if (err) {
                    console.log(err);
                  }
                  else {
                    console.log("Deleted successfully");

                    postRef.remove();
                    userRef.remove();
                    hotRef.remove();
                    likesRef.remove();

                    req.flash('success_msg','Post Deleted');
                    res.send(200);
                  }
            });
        }    
    });
});

---

SITUATION:

I added delete buttons so the user could delete his posts.

When the user clicks the button an AJAX request is made to my Node.js server.

But I get the following error:

---

ERROR:

net::ERR_EMPTY_RESPONSE

---

QUESTION:

What is this error and how do I fix it ?

Answer 1

The response you're getting is actually correct . Per the docs , Firebase returns a 200 status code and an empty response . net::ERR_EMPTY_RESPONSE is exactly that. What you should do is check for both null and a 200 status code in the response; if true, you can safely assume that the post was deleted.

My personal opinion is that Firebase should really consider returning something more substantial than nothing and a generic, catch-all status code. I'd prefer something like 204 No Content, or 410 Gone. But, alas.

—

Side note: this conditional will never return anything if the post doesn't belong to the author — your API should still return something (an error, probably in this case) even if your conditional doesn't match. Like:

if (firebase.auth().currentUser.uid.toString() == author) { 
    // your code
} else {
    res.status(401).send("User does not have permission to complete the operation.")
}