Read data from Realtime Database

Khalid Khan

The code imports the db module and exports a function that takes two arguments: a request object and a response object.

If the request object doesn't have an id query parameter, the function returns a response with a status code of 400 and an error message containing the word "Missing."

If the request does have an id query parameter, the function fetches the requested table's ref (object) and returns a reference to that ref. The function then uses that reference to execute a once clause that takes two arguments: a snapshot (object) and a function that returns a response.

The function calls the the ref's once() method with the snapshot argument as the first parameter and the function that handles the response as the second parameter. The once() method returns a response with a status code of 200 and a JSON object that contains the following properties:

total: The value of the snapshot.

Shortcut: firebase.web.realtimedb

import db from '../../lib/db-admin';

export default (req, res) => {
  if (!req.query.id) {
    return res.status(400).json({
      error: 'Missing "id" query parameter'
    });
  }

  const ref = db.ref('table').child(req.query.id);

  return ref.once('value', (snapshot) => {
    res.status(200).json({
      total: snapshot.val()
    });
  });
};