# Error found on console: "Failed to read input"

**URL:** <https://discourse.dojo.io/t/error-found-on-console-failed-to-read-input/278>\
**Category:** DWR users\
**Created:** [September 11, 2018, 9:23pm UTC](https://discourse.dojo.io/t/error-found-on-console-failed-to-read-input/278 "2018-09-11T21:23:04Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![lucasjohn](https://avatars.discourse-cdn.com/v4/letter/l/b487fb/32.png) [@lucasjohn](https://discourse.dojo.io/u/lucasjohn)\
**Post date:** [September 11, 2018, 9:23pm UTC](https://discourse.dojo.io/t/error-found-on-console-failed-to-read-input/278/1 "2018-09-11T21:23:04Z")

</div>

I’m seeking some help regarding the dwr error found on console after observing the behavior for a while.  
Tested with version 2.0.3 and 2.0.11.

Sometimes a request fails, as follows…

Error message on console:

> engine.js:1311 Error: org.directwebremoting.extend.ServerException, Failed to read input

After this trace:

> | dwr.engine.\_debug | @ | engine.js:1310  
> | dwr.engine.\_handleError | @ | engine.js:1077  
> | dwr.engine.\_remoteHandleBatchException | @ | engine.js:941  
> | (anonymous) | @ | VM505:3  
> | dwr.engine.\_eval | @ | engine.js:980  
> | dwr.engine.\_stateChange | @ | engine.js:869  
> | batch.req.onreadystatechange | @ | engine.js:646  
> | XMLHttpRequest.send (async) | |  
> | dwr.engine.\_sendData | @ | engine.js:678  
> | dwr.engine.endBatch | @ | engine.js:212  
> | dwr.engine.\_execute | @ | engine.js:403  
> | MyDwr.isActive | @ | MyDwr.js:84  
> | setInterval (async) | |  
> | n | @ | jquery.js:2  
> | fireWith | @ | jquery.js:2  
> | ready | @ | jquery.js:2  
> | B | @ | jquery.js:2

---

<div class="post-metadata">

**Author:** ![mikewse](https://avatars.discourse-cdn.com/v4/letter/m/58956e/32.png) [@mikewse](https://discourse.dojo.io/u/mikewse)\
**Post date:** [September 12, 2018, 9:59am UTC](https://discourse.dojo.io/t/error-found-on-console-failed-to-read-input/278/2 "2018-09-12T09:59:39Z")

</div>

First I would recommend you to upgrade to the latest DWR 3 version. DWR 2 is no longer being maintained.

The error you are seeing means that the appserver is complaining about not receiving the announced data from the browser. This usually doesn’t mean there is an actual application bug but rather is correlated to environmental factors, user behaviour (pressing abort or refresh?) or browser quirks.

You can find more info on our old forum archive at Nabble, f ex these threads:  
[http://dwr.2114559.n2.nabble.com/Input-Read-Failed-Failed-HTTP-POST-td5405611.html](http://dwr.2114559.n2.nabble.com/Input-Read-Failed-Failed-HTTP-POST-td5405611.html)  
[http://dwr.2114559.n2.nabble.com/Failed-to-Read-Input-td5404962.html](http://dwr.2114559.n2.nabble.com/Failed-to-Read-Input-td5404962.html)

---

<div class="post-metadata">

**Author:** ![lucasjohn](https://avatars.discourse-cdn.com/v4/letter/l/b487fb/32.png) [@lucasjohn](https://discourse.dojo.io/u/lucasjohn)\
**Post date:** [September 12, 2018, 11:08pm UTC](https://discourse.dojo.io/t/error-found-on-console-failed-to-read-input/278/3 "2018-09-12T23:08:02Z")

</div>

Hello, Mike!  
Thank you for the reply.  
I’ll analyse the suggestion on the post and also try the new version.

---

<div class="post-metadata">

**Author:** ![lucasjohn](https://avatars.discourse-cdn.com/v4/letter/l/b487fb/32.png) [@lucasjohn](https://discourse.dojo.io/u/lucasjohn)\
**Post date:** [September 24, 2018, 6:07pm UTC](https://discourse.dojo.io/t/error-found-on-console-failed-to-read-input/278/4 "2018-09-24T18:07:07Z")

</div>

After testing multiple versions and finally 3.0.2RELEASE, I still got the same message: “Failed to read Input”.

Well, I hope it leads somehow to understanding why it happens.  
One difference I could observe testing in different servers is that the more loaded (more number of apps in the appServer) would throw the error more often.

The stacktrace is this one below:

> engine.js:984 console.trace  
> dwr.engine.\_debug @ engine.js:984  
> (anonymous) @ SWB\_events.shtm:99  
> (anonymous) @ engine.js:794  
> logHandlerEx @ engine.js:2553  
> (anonymous) @ engine.js:791  
> ignoreIfUnloading @ engine.js:601  
> dwr.engine.\_handleError @ engine.js:772  
> validate @ engine.js:2442  
> complete @ engine.js:1568  
> stateChange @ engine.js:1792  
> batch.req.onreadystatechange @ engine.js:1664  
> XMLHttpRequest.send (async)  
> send @ engine.js:1691  
> send2 @ engine.js:1561  
> send @ engine.js:1525  
> dwr.engine.endBatch @ engine.js:279  
> dwr.engine.\_execute @ engine.js:694  
> p.doLongPoll @ MiscDwr.js:256  
> mango.longPoll.poll @ common.js:75  
> setTimeout (async)  
> mango.longPoll.pollCB @ common.js:118  
> (anonymous) @ engine.js:1037  
> logHandlerEx @ engine.js:2553  
> handleCallback @ engine.js:1033  
> (anonymous) @ VM51:10  
> (anonymous) @ VM51:11  
> dwr.engine.\_executeScript @ engine.js:720  
> stateChange @ engine.js:1791  
> batch.req.onreadystatechange @ engine.js:1664  
> XMLHttpRequest.send (async)  
> send @ engine.js:1691  
> send2 @ engine.js:1561  
> send @ engine.js:1525  
> dwr.engine.endBatch @ engine.js:279  
> dwr.engine.\_execute @ engine.js:694  
> p.doLongPoll @ MiscDwr.js:256  
> mango.longPoll.poll @ common.js:75  
> setTimeout (async)  
> mango.longPoll.pollCB @ common.js:118  
> (anonymous) @ engine.js:1037  
> logHandlerEx @ engine.js:2553  
> handleCallback @ engine.js:1033  
> (anonymous) @ VM45:10  
> (anonymous) @ VM45:11  
> dwr.engine.\_executeScript @ engine.js:720  
> stateChange @ engine.js:1791  
> batch.req.onreadystatechange @ engine.js:1664  
> XMLHttpRequest.send (async)  
> send @ engine.js:1691  
> send2 @ engine.js:1561  
> send @ engine.js:1525  
> dwr.engine.endBatch @ engine.js:279  
> dwr.engine.\_execute @ engine.js:694  
> p.doLongPoll @ MiscDwr.js:256  
> mango.longPoll.poll @ common.js:75  
> setTimeout (async)  
> mango.longPoll.pollCB @ common.js:118  
> (anonymous) @ engine.js:1037  
> logHandlerEx @ engine.js:2553  
> handleCallback @ engine.js:1033  
> (anonymous) @ VM39:10  
> (anonymous) @ VM39:11  
> dwr.engine.\_executeScript @ engine.js:720  
> stateChange @ engine.js:1791  
> batch.req.onreadystatechange @ engine.js:1664  
> XMLHttpRequest.send (async)  
> send @ engine.js:1691  
> send2 @ engine.js:1561  
> send @ engine.js:1525  
> dwr.engine.endBatch @ engine.js:279  
> dwr.engine.\_execute @ engine.js:694  
> p.doLongPoll @ MiscDwr.js:256  
> mango.longPoll.poll @ common.js:75  
> mango.longPoll.pollCB @ common.js:123  
> (anonymous) @ engine.js:1037  
> logHandlerEx @ engine.js:2553  
> handleCallback @ engine.js:1033  
> (anonymous) @ VM38:10  
> (anonymous) @ VM38:11  
> dwr.engine.\_executeScript @ engine.js:720  
> stateChange @ engine.js:1791  
> batch.req.onreadystatechange @ engine.js:1664  
> engine.js:985 Error: org.directwebremoting.extend.ServerException, Failed to read input

Another example:

> engine.js:984 console.trace  
> dwr.engine.\_debug @ engine.js:984  
> (anonymous) @ advanced.shtm:90  
> (anonymous) @ engine.js:794  
> logHandlerEx @ engine.js:2553  
> (anonymous) @ engine.js:791  
> ignoreIfUnloading @ engine.js:601  
> dwr.engine.\_handleError @ engine.js:772  
> validate @ engine.js:2442  
> complete @ engine.js:1568  
> stateChange @ engine.js:1792  
> batch.req.onreadystatechange @ engine.js:1664  
> XMLHttpRequest.send (async)  
> send @ engine.js:1691  
> send2 @ engine.js:1561  
> send @ engine.js:1525  
> dwr.engine.endBatch @ engine.js:279  
> dwr.engine.\_execute @ engine.js:694  
> p.getActiveAlarmCountByUser @ MiscDwr.js:217  
> (anonymous) @ advanced.shtm:283  
> setInterval (async)  
> (anonymous) @ advanced.shtm:273  
> n @ jquery.js:2  
> fireWith @ jquery.js:2  
> ready @ jquery.js:2  
> B @ jquery.js:2  
> engine.js:985 Error: org.directwebremoting.extend.ServerException, Failed to read input

---

<div class="post-metadata">

**Author:** ![mikewse](https://avatars.discourse-cdn.com/v4/letter/m/58956e/32.png) [@mikewse](https://discourse.dojo.io/u/mikewse)\
**Post date:** [September 24, 2018, 11:29pm UTC](https://discourse.dojo.io/t/error-found-on-console-failed-to-read-input/278/5 "2018-09-24T23:29:02Z")

</div>

Ok so as I said previously this is an error occurring on the server. The stack trace you see on the client shows that a call was made to the server and an error response from the server was (successfully) transmitted back to the client. So there’s nothing to see really from the client side.

The question is what is going on with the server. You should check the server log and look for the cause of the `org.directwebremoting.extend.ServerException` that was echoed back to the client. There will always be a nested exception.