I am trying to create a website (for personal use) where people can text each other, upload files / photos etc.

I would like to generate a token for every user in the database just to identify them without nicknames. I've got a function that generates a token and a database where I've got all my users.

The problem is I don't really know how to check if:
a) the user already exists in the database.
b) if exists how to assign them the token.
c) if doesn't create a new one and also assign them the token.

Here is my code, I wrote everything in JS using Google Firebase

firebase.initializeApp(firebaseConfig);
const db = firebase.database();

const username = prompt("Username:");
const receiver = prompt("Receiver's name:");

document.getElementById("send-message").addEventListener("submit", postChat);
function postChat(e)
{
    e.preventDefault();
    const timestamp = Date.now();
    const chatTxt = document.getElementById("chat-txt");
    const message = chatTxt.value;
    chatTxt.value = "";
    db.ref("messages/"   username   "/"   receiver   "/"   timestamp).set({
        usr: username,
        msg: message,
    });

    db.ref("messages/"   receiver   "/"   username   "/"   timestamp).set({
        usr: username,
        msg: message,
    });
}

const fetchChat = db.ref("messages/"   username   "/"   receiver   "/");
fetchChat.on("child_added", function (snapshot)
{
    const messages = snapshot.val();
    const msg = "<li>"   messages.usr   " : "   messages.msg   "</li>";
    document.getElementById("messages").innerHTML  = msg;
});

That is how I generate a token

function generateAToken()
{
    let characters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
    let token = "";

    for(let i = 0; i < 32; i  )
    {
        let tmp = Math.floor(Math.random() * 62);
        token  = characters[tmp];
    }
}

Everything works really well right now, the point is when I type something in the prompts it immediately runs a function that solves the key problem which I described above.

That is how the JSON looks like right now

{
  "messages": {
    "user1": {
      "user2": {
        "1656608940603": {
          "msg": "hi",
          "usr": "user1"
        },
        "1656608958447": {
          "msg": "hey, whats good?",
          "usr": "user2"
        }
      }
    },
    "user2": {
      "user1": {
        "1656608940603": {
          "msg": "hi",
          "usr": "user1"
        },
        "1656608958447": {
          "msg": "hey, whats good?",
          "usr": "user2"
        }
      }
    }
  }
}

And here is a screen of how the website looks like right now if the username and receiver's names are user1 and user2.
Enter image description here!

I am kind of new in the environment so please if someone wants to help use easy language as you would talk to a kid.
Have a nice day to everyone ;)

CodePudding user response：

Generally, A token should not be saved in the database,

What I think is that :

the user enters username and password, in your code you will encrypt the password on registration using some algorithm or a library (crypto, JWT).

At login - Validate that the user's encrypted password from the database (registration phase), is same as the password encrypted at login (login phase).

So breaking into points:

1. User registers -> Password saved in database after encryption.

2. User logins -> Validate encrypted password same as the current password after encryption.

I hope what I say make sense haha.