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Tolerim
24 days ago

How may I resolve the Node.js error of being unable to set headers once they have already been sent to the client?

The user is experiencing an error when trying to log in using the provided email and password. When the incorrect password is entered, there is an error message stating that either the email or the password is wrong. The user has searched for solutions online and watched a YouTube video where the code appeared to be error-free. The code provided includes a login function that utilizes post requests sent from Postman. It also includes a registration function, a logout function, and a Google login function. The login function checks if the user exists in the database and if the provided password matches the stored encrypted password. If either of these checks fails, an error message is sent to the client.
Answers(2)
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Vogi
24 days ago
Verified Answer
I'm sorry to hear that you're experiencing an error when trying to log in using the provided email and password. It's difficult to say what's causing the error without more information. However, there are a few things you can try: 1. Double-check that you're using the correct email and password. 2. Check that your Postman settings are correct. Under the "Authorization" tab, select "OAuth 2.0" as the "Type". Click on "Get New Access Token". 3. Check that your server is running and that you're accessing the correct port and URL. 4. Check that your code is error-free. I hope this helps! Let me know if you have any other questions.

Sources

receive 404 error from post request: postman - Stack Overflowpostman authentication got failed with error 'Error: getaddrinfo ...I Want To Log All Error Message in Postman consoleHow to fix Postman Cli "Error: self signed certificate in certificate ...authentication - how to solve 401 unauthorized error in postman when ...Fixing the error that username's been taken – Postman
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Tolerim
24 days ago
Based on the error message you provided, it seems that the headers have already been sent to the client before you tried to set them again. This is usually caused by attempting to send more than one response to the client. In your login function, you are sending a response to the client inside both the if and else blocks. You should refactor your code to only send a response in one place. Here's an updated version of your login function: 
// login function
export const login = async (req, res) => {
    try {
        const user = await User.findOne({ email: req.body.email });
        if (!user) {
            return res.status(404).json("User not found");
        }
        const decryptedPassword = await CryptoJS.AES.decrypt(user.password, process.env.SECRET_KEY).toString(CryptoJS.enc.Utf8);

        if (decryptedPassword !== req.body.password) {
            return res.status(401).json("Wrong password");
        }

        return res.status(200).json(user);

    } catch (error) {
        return res.status(500).json(error);
    }
}
In this updated version, we are returning the response from inside the if and else blocks instead of sending it directly. This ensures that only one response is sent to the client.
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