Mongoose CastError: Cast to ObjectId failed for Twitter ID (type string)

Question

I’m working on a content syndication project where I’m implementing Twitter authentication using Passport.js and Mongoose. The authentication flow works up to the point of deserializing the user. I’m encountering a CastError when trying to deserialize the user data from MongoDB.

Current Status:

• Twitter authentication has been set up.
• Backend and frontend servers are running.
• Encountering issues with deserializing user data.

Issues Encountered:

1. CastError

CastError: Cast to ObjectId failed for value "1520050647713918976" (type string) at path "_id" for model "User"

2. Callback URL not approved:

Error: Callback URL not approved for this client application. Approved callback URLs can be adjusted in your application settings

Steps Taken: Updated deserialization logic to query twitterId instead of _id.

passport.deserializeUser(async (id, done) => {
    console.log("Deserializing user with twitterId:", id);
    try {
        const user = await User.findOne({ twitterId: id });
        if (user) {
            console.log("User found:", user);
            done(null, user);
        } else {
            console.log("No user found with twitterId:", id);
            done(null, null);
        }
    } catch (error) {
        console.error("Error in deserializeUser:", error);
        done(error, null);
    }
});

Verified that the MongoDB schema for the User model has twitterId as a string.

const mongoose = require('mongoose');
const UserSchema = new mongoose.Schema({
    twitterId: { type: String, unique: true },
    displayName: String,
    photos: [String]
});
const User = mongoose.model('User', UserSchema);

Checked and updated the callback URL in the Twitter developer settings to match the URL in the .env file.

Added more detailed error logging in the passport.js file.

Next Steps:

1. Verify the callback URL in the Twitter developer settings matches the URL in the .env file and the route being hit in the application.
2. Check if the Twitter ID is correctly being saved in the MongoDB database.
3. Continue debugging the deserialization process to ensure User.findOne({ twitterId: id }) is correct.
4. Ensure both the frontend (localhost:3000) and backend (localhost:5001) are running and communicating correctly.
5. If the issue persists, consider creating a separate test project to isolate and debug the Twitter authentication logic.

Environment: Node.js v22.2.0 MongoDB Atlas Passport.js Mongoose

Any help or insights on resolving these issues would be greatly appreciated!

Answer 1

CastError: Cast to ObjectId failed for value "1520050647713918976" (type string) at path "_id" for model "User"

It means that the system had tried to cast the given string value "1520050647713918976" to the type ObjectId but it did not succeed in it. Therefore it threw an error.

In technical terms, this casting is a call to the function ObjectId().

The system invoked the function as below. If we try the same in Mongo Shell, we shall get an error which is also shown below. The error message tells us what is a valid input. It must be one of the three items - hex string, 12 byte array or an integer. It can also be invoked without an input. In all other cases, it will fail. This is what happens in our case. The given text value "1520050647713918976" does not conform to a valid input. For more about it, please refer to the link in citation.

const newObjectId =  ObjectId("1520050647713918976");

BSONError: input must be a 24 character hex string, 12 byte Uint8Array, or an integer

Please note that the above error when reported through Mongoose, it will be formatted as what you have seen in your case. However the thing happening under the hood is the same.

The following query which you have already written is surely an alternate for this requirement.

const user = await User.findOne({ twitterId: id });

However the deserialisation query based on _id can also be made working. If it is required, during serialisation, user.id must be assigned with the value of _id. Then the call - done(null, user.id) will make the value of_id persisting in the session. And the deserialisation query below will work with no cast error.

const user = await User.findOne({ _id: id });

Citation:

ObjectId()

Cast Errors

Understanding passport serialize deserialize