Windows (only?) Null Buffer Length

[NewETown]

Found someone else on SO posting about this so I thought I'd make an issue here. For those working in Windows or deploying to Azure Web Apps, we're all running into a null reference error determining the length of the write buffer here:

string_decoder.js:66
var buflen = buffer.length;

TypeError: Cannot read property 'length' of null
    at StringDecoder.write (string_decoder.js:66:22)
    at Interface._normalWrite (readline.js:319:30)
    at Interface.write (readline.js:310:49)
    at message.converse.makeActionCallback.runActions.interactive.rl.on [as interactive] (D:\R&D\witai\node_modules\node-wit\lib\wit.js:286:13)
    at Object.<anonymous> (\witai\node_modules\node-wit\examples\template.js:29:8)

http://stackoverflow.com/questions/37266010/wit-ai-example-code-error-null-buffer-length

This can be reproduced on a Mac/Linux machine if you install Visual Studio Code and run the debugger with this as your launch.json:

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Launch",
            "type": "node",
            "request": "launch",
            "program": "${workspaceRoot}/app.js",
            "stopOnEntry": false,
            "args": [],
            "cwd": "${workspaceRoot}",
            "preLaunchTask": null,
            "runtimeExecutable": null,
            "runtimeArgs": [
                "--nolazy",
                "--harmony"
            ],
            "env": {
                "NODE_ENV": "development"
            },
            "externalConsole": false,
            "sourceMaps": false,
            "outDir": null
        },
        {
            "name": "Attach",
            "type": "node",
            "request": "attach",
            "port": 3000,
            "address": "localhost",
            "restart": false,
            "sourceMaps": false,
            "outDir": null,
            "localRoot": "${workspaceRoot}",
            "remoteRoot": null
        }
    ]
}

For what it's worth this can be fixed by updating to this:

this.rl.on('line', ((line) => {
      const msg = line.trim();
      this.runActions(
        sessionId,
        msg,
        this.context,
        (error, context) => {
          if (error) {
            l.error(error);
          } else {
            this.context = context;
          }
          this.rl.prompt();
          this.rl.write('', {ctrl: true, name: 'e'});
        },
        steps
      );
    }).bind(this));

Just replace the null with an empty string. Seems trivial, I'm not sure why this is happening. NPM version 3.8.1, "node-wit": "^3.3.0", "node": "0.12.6"

[yaalisri]

Thanks for the workaround!! I was searching for this...

[StrongBearCeo]

I've got the same problem when trying to run in Meteor shell which is similar to node shell. I'm using ubuntu 14.04 server

Here is my wit client

> WitAPI.wit
Wit {
  config:
   { accessToken: 'xxxxxxxxxxxxxxxx',
     actions:
      { send: [Function: send],
        clearContext: [Function: clearContext],
        clearContextAndSession: [Function: clearContextAndSession],
        addExpenseInit: [Function: addExpenseInit],
        addExpenseEnoughContext: [Function: addExpenseEnoughContext],
        addExpenseMissingAmount: [Function: addExpenseMissingAmount],
        addExpenseMissingDesc: [Function: addExpenseMissingDesc],
        addExpenseFinalize: [Function: addExpenseFinalize],
        transactionChangeOptions: [Function: transactionChangeOptions],
        transactionChangeAskDate: [Function: transactionChangeAskDate],
        transactionChangeAskAmount: [Function: transactionChangeAskAmount],
        transactionChangeAskDesc: [Function: transactionChangeAskDesc],
        receivedMisc: [Function: receivedMisc],
        replyMisc: [Function: replyMisc],
        setLimitInit: [Function: setLimitInit],
        askExpenseLimitAmount: [Function: askExpenseLimitAmount],
        setLimitEnoughContext: [Function: setLimitEnoughContext],
        setLimit: [Function: setLimit],
        updateTransaction: [Function: updateTransaction],
        removeTransaction: [Function: removeTransaction],
        listTransaction: [Function: listTransaction],
        reportTransaction: [Function: reportTransaction],
        removeLimit: [Function: removeLimit],
        showLimit: [Function: showLimit],
        setLanguage: [Function: setLanguage],
        changeLanguage: [Function: changeLanguage],
        offerHelp: [Function: offerHelp],
        showHelpMenu: [Function: showHelpMenu] },
     witURL: 'https://api.wit.ai',
     apiVersion: '20160516',
     headers:
      { Authorization: 'Bearer xxxxxxxxxxxx',
        Accept: 'application/vnd.wit.20160516+json',
        'Content-Type': 'application/json' },
     logger:
      Logger {
        level: 'info',
        debug: [Function: noop],
        info: [Function: bound bound ],
        warn: [Function: bound bound ],
        error: [Function: bound bound ] } },
  _sessions: {},
  message: [Function],
  converse: [Function],
  runActions: [Function] }

When I try to run in interactive mode

> interactive(WitAPI.wit)
string_decoder.js:66
  var buflen = buffer.length;
                     ^
TypeError: Cannot read property 'length' of null
    at [object Object].StringDecoder.write (string_decoder.js:66:22)
    at Interface._normalWrite (readline.js:320:30)
    at Interface.write (readline.js:311:49)
    at prompt (/home/bitnami/sn-webapp/node_modules/node-wit/lib/interactive.js:24:8)
    at module.exports (/home/bitnami/sn-webapp/node_modules/node-wit/lib/interactive.js:26:3)
    at repl:1:-61
    at packages/shell-server/shell-server.js:458:25
    at /home/bitnami/.meteor/packages/promise/.0.8.8.1jn8psc++os+web.browser+web.cordova/npm/node_modules/meteor-promise/fiber_pool.js:32:39
>