node.js error message events.js:183 throw er; // U

问题:

Playing around Microsoft's botframework, when I try to run the app.js file, which is the main file of the bot, the first time is fine, after I close the bot emulator, and all programs, and run the app.js again, this error message pops out

events.js:183
      throw er; // Unhandled 'error' event
      ^

Error: listen EADDRINUSE :::3978
    at Object._errnoException (util.js:1022:11)
    at _exceptionWithHostPort (util.js:1044:20)
    at Server.setupListenHandle [as _listen2] (net.js:1351:14)
    at listenInCluster (net.js:1392:12)
    at Server.listen (net.js:1476:7)
    at Server.listen (C:\Users\yu\Documents\GitHub\BotBuilder-
Samples\Node\cards-AdaptiveCards\node_modules\restify\lib\server.js:404:32)
    at Object.<anonymous> (C:\Users\yu\Documents\GitHub\BotBuilder-
Samples\Node\cards-AdaptiveCards\app.js:10:8)
    at Module._compile (module.js:643:30)
    at Object.Module._extensions..js (module.js:654:10)
    at Module.load (module.js:556:32)

I found some solution to this, It looks like the port 3978 was taken when I run the js file for the second time, and I have to use cmd to find which task is using that port, and then kill the task.

C:\>netstat -aon|findstr 3978

so this one is taking the port, although I already closed all programs

TCP    0.0.0.0:3978           0.0.0.0:0              LISTENING       13140
TCP    [::]:3978              [::]:0                 LISTENING       13140

actually it is node.exe itself, it still running at background

C:\Users\yu>tasklist|findstr 13140
node.exe                     13140 Console                    1     42,064 K

and I need to kill it

C:\Users\yu>taskkill /f /t /im node.exe

Is there a way to not always repeat doing this when I want to run the file more than one time, it just starts to go wired today, and I mean for all different app.js files, include offical sample code. For the past one month, everything was fine, the IDE I am using is sublime text 3, node.js version is 8.9.4 lts

回答1:

This is a very common issue and can be easily fixed by either of the below methods.

1. Try to close the process that is using your port.

   netstat -tulnp | grep <port_number>

2. Installing the below pakcage fixed it for me forever.

   npm install ws@3.3.2 --save-dev --save-exact

3. Run this command in your terminal :

   echo fs.inotify.max_user_watches=524288 | sudo tee -a /etc/sysctl.conf && sudo sysctl -p

   For Arch Linux add this line to /etc/sysctl.d/99-sysctl.conf:

   fs.inotify.max_user_watches=524288

   Then execute:

   sysctl --system

   This will also persist across reboots.

   https://github.com/guard/listen/wiki/Increasing-the-amount-of-inotify-watchers#the-technical-details

Either one of the solutions will work . If not then restart your system and check again.

回答2:

I also got the same problem and tried many ways but finally got this ,this work well

npm install ws@3.3.2 --save-dev --save-exact

refer to this link for more clarifications https://github.com/ionic-team/ionic-cli/issues/2922

回答3:

Try specify a different port before you run the node.js application.

For example, if you have collision on port 3978, set a different port before you start the server.js:

export PORT=3979

回答4:

If you are on mac, to make sure nothing is running on the same port, do:

killall node

and restart your app.

回答5:

The port you are listening to is already being listened by another process.

When I faced to this error I killed the process using Windows PowerShell (because I used Windows)

1. open the windows powershell
2. type ps and then you can get list of processes
3. find the process named node, and note the Id
4. type Stop-process <Id>

I think that it is help for windows users.

回答6:

Even I was also getting the error while running node server. i.e events.js:183 throw er; // Unhandled 'error' event ^ In my case, I was getting that error because I had changed Mysql port number 3306 to 3307 while installing. I recovered from from that error by changing Mysql port number to 3306, and now its running.

回答7:

I did also face the same problem. Installing of npm install ws@3.3.2 --save-dev --save-exact was not fix this. Later I came to know that there is an another website hosted by IIS in the same port where I configured for Node JS express server. Stopping of IIS website can get rid out of this issue.

回答8:

Find the process that is using the port and kill it.

Assuming the server port is 8000.

1) C:> netstat -aon | findstr 8000

This command will return the Process ID (PID).

2) C:> taskkill /F /PID 7848

This command will kill the Process by PID.

回答9:

I experienced the same problem. Installing this package solved it permanently:

npm install ws@3.3.2 --save-dev --save-exact