Latest master (newer than 2.2.16) throws exception

[smassin]

Issue Description

The latest master or newer than 2.2.16 is throwing an exception and crashing whenever making a query.

Whenever a query is made the following error occurs in the logs:

Error: Can't set headers after they are sent.
at ServerResponse.OutgoingMessage.setHeader (_http_outgoing.js:344:11)
at expressInit (.../node_modules/express/lib/middleware/init.js:23:42)
at Layer.handle as handle_request
at trim_prefix (.../node_modules/express/lib/router/index.js:312:13)
at .../node_modules/express/lib/router/index.js:280:7
at Function.process_params (.../node_modules/express/lib/router/index.js:330:12)
at next (.../node_modules/express/lib/router/index.js:271:10)
at query (.../node_modules/express/lib/middleware/query.js:49:5)
at Layer.handle as handle_request
at trim_prefix (.../node_modules/express/lib/router/index.js:312:13)

I couldn't find anything on ParseServer.js:431 that seemed related though.
Using [email protected] works just fine.

Steps to reproduce

Please include a detailed list of steps that reproduce the issue. Include curl commands when applicable.

1. Install the latest parse-server (npm install parse-server)
2. Launch the server. (I'm using forever to run it with node)
3. Make any cloud request with a query.

Expected Results

No error.

Actual Outcome

Server throws exception:
Error: Can't set headers after they are sent.

Environment Setup

• Server
  • parse-server version: 2.2.17 ?
  • Operating System: Ubuntu
  • Localhost or remote server? (AWS, Heroku, Azure, Digital Ocean, etc): Azure
• Database
  • MongoDB version: N/A
  • Storage engine: N/A
  • Hardware: N/A
  • Localhost or remote server? (AWS, mLab, ObjectRocket, Digital Ocean, etc): Azure

Logs/Trace

Oddly enough VERBOSE made the error message go away but the problem still exists.

However, from my own logs I can tell this is happening every time a query is made.

[tillifywebb]

Yes we have same error, we have rolled back as it was crashing our app

#2338

[j-koenig]

Same here...

[johnnydimas]

I had the same issue after I updated as well.

I am using express to catch any errors, so what I did was check if the response headers had already been sent to the client before handling my errors.

This seems to take care of it for me for now so I can continue with the latest parse, but not sure if there is a fix or better solution to this out there.

// catch 404 and forward to error handler
app.use(function(req, res, next) {
    // Fixes issue with cloud code
    if (res.headersSent) {
        return next(err);
    }
    var err = new Error('Not Found');
    err.status = 404;
    next(err);
});

// production error handler
// no stacktraces leaked to user
app.use(function(err, req, res, next) {
   // Fixes issue with cloud code
   if (!res.headersSent) {
        res.status(err.status || 500);
        res.render('error', {
            message: err.message,
            error: {}
        });
    }
});

There is some documentation for this also on the express site at the bottom under the heading "The Default Error Handler".

http://expressjs.com/en/guide/error-handling.html

[flovilmart]

Closing as duplicate of #2362