在 POST 方法中传递值

Question

I am trying to pass the value or a variable using JS to my Django BackEnd.

When click on a Like Button, I am getting the ID of the post and a variable called Iliked saying "yes" or "no" depending if the user already liked the clicked post or not.

When I click on Like on Post 77 with my user Bar, I then get in console log:

• id = 77
• Iliked = yes

Since my API allows to pass the ID within its URL, all I care about is to pass the Iliked value in order to have my Views.py update the DB accordingly:

document.addEventListener('DOMContentLoaded', function() {

document.querySelectorAll('#likebtn').forEach(item => {
            item.addEventListener('click', () => {
                const id = item.getAttribute('data-id');
                const Iliked = item.getAttribute('data-Iliked');
                like(id, Iliked);
            });
        });

})

function like(id, Iliked) {
    console.log (id)
    console.log (Iliked)

        fetch(`/like/${id}`, {
            method: 'POST',
            credentials: 'same-origin',
            headers:{
                'Accept': 'application/json',
                'X-Requested-With': 'XMLHttpRequest',
        },
            body: JSON.stringify({
                Iliked:'Iliked'
            })
        })
        .then(response => {return response.json()})
        .then(data => {
        console.log (data)
        })

return false;

}

@login_required
@csrf_exempt
def like(request, id):

    if request.method == "POST":
        CurrentUser = request.user.id
        Iliked = json.load(request)['Iliked'] #Get data from POST request
        print("This is the JSON Iliked received from the front end : ", Iliked)

        if Iliked == 'no':

            Liker = User.objects.get(user=CurrentUser)
            ThePostToLike = Post.objects.get(id=id)
            ThePostToLike.like.add(Liker)
            ThePostToLike.save()
            Iliked == 'yes'
            print("The like is now ADDED")

        elif Iliked == 'yes':

            Liker = User.objects.get(user=CurrentUser)
            ThePostToLike = Post.objects.get(id=id)
            ThePostToLike.like.remove(Liker)
            ThePostToLike.save()
            Iliked == 'no'
            print("The like is now REMOVED")
        
        databack = {
            'Iliked': Iliked,
        }

        return JsonResponse(databack, safe=False)

The problem that I have here is that I am loosing the value (yes/no) of Iliked when using JSON.stringify().

When I load "Iliked" in the backend, its value is "Iliked" instead of yes/no.

This in turns totally bypass my DB logic and returns "Object { Iliked: "Iliked" }" back to the front end.

Hope you can help !

EDIT:

Models

class User(AbstractUser):
    pass

class Post(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    timestamp = models.DateTimeField(auto_now_add=True)
    post = models.CharField(max_length=350, null=True, blank=True)
    like = models.ManyToManyField("User", blank=True, related_name="like_amount")

With the '' removed as per @DeepSpace, my logic now works.

However, I am hit by:

    raise FieldError("Cannot resolve keyword '%s' into field. "
django.core.exceptions.FieldError: Cannot resolve keyword 'user' into field. Choices are: date_joined, email, first_name, follower_name, following_name, groups, id, is_active, is_staff, is_superuser, last_login, last_name, like_amount, logentry, password, post, profile, user_permissions, username
[21/Feb/2021 16:23:18] "POST /like/77 HTTP/1.1" 500 18572

Answer 1

When I load "Iliked" in the backend, its value is "Iliked" instead of yes/no.

Because that's what you set it to:

body: JSON.stringify({
            Iliked: 'Iliked'
        })

Remove the '' so it is not a string, but the value of the variable:

body: JSON.stringify({
                Iliked: Iliked
            })

Then you can use the JS shortcut:

body: JSON.stringify({ Iliked })

{ Iliked } creates an object, with a single key-value pair where the key is 'Iliked' and the value is the value of the variable Iliked .

Answer 2

As suggested, I was passing a literal string instead of a var:

BAD (Iliked passed as string)

            body: JSON.stringify({
                Iliked:'Iliked'
            })

GOOD (Iliked passed as a variable)

            body: JSON.stringify({
                Iliked:Iliked
            })

For the second question, I was trying to get Liker = User.objects.get(user=CurrentUser) while user expects a string. Changing it to id did the trick: Liker = User.objects.get(id=CurrentUser)