CODEWITHSUNDEEP
mysqlnode.jsexpress
Matt
Matt

Reputation: 1432

Why can't I send a response in Express from a mysql query?

I'll keep the code simple, but basically, I have a Node.js server running Express. Express is connected to a MySQL database using pooling (and the mysql npm package). This is what my server looks like (I left out the boring requires and whatnot to keep this simple). This is the only routing that the server handles.

server.all('/test', function (req, res, next) {
    pool.getConnection(function (err, conn) {
        if (err) {
            console.log(err);
        }
        else {
            conn.query("select * from spwp_appusers where id=46", function (err, rows) {
                conn.release();

                if (err) {
                    console.log(err);
                }
                else {
                    res.send(200);
                }
            });
        }
    });

    next();
});

However, when I run this code, the server tries to execute res.send(200); but breaks and I get the following error:

/usr/lib/node_modules/mysql/lib/protocol/Parser.js:77
        throw err; // Rethrow non-MySQL errors
        ^

Error: Can't set headers after they are sent.
    at ServerResponse.OutgoingMessage.setHeader (_http_outgoing.js:335:11)

Does anyone know what is happening? Why can't I send the response? Even when I use a callback, I get this error.

Upvotes: 1

Views: 3917

Answers (2)

Prabhakar Pandey
Prabhakar Pandey

Reputation: 83

I think the problem is with next. try changing next(); inside getConnection()

Upvotes: 3

Ramesh
Ramesh

Reputation: 1555

above error show in my case mismatch my mysql user,password,db name so please check your mysql credential.

var pool = mysql.createPool({ host: 'localhost', user: 'root', password: '', database: 'dbname', multipleStatements: true });

Upvotes: 0

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