Cannot read property 'stdin' of null

[w0rm]

Hello! Thanks for this wonderful wrapper that makes interaction with phantom much simpler and straightforward.

I am using phridge to generate png sprite from svg sources. Yesterday I received an issue from someone using my gulp plugin: https://github.com/w0rm/gulp-svgfallback/issues/7 with an error message coming from phridge sources.

I am not able to reproduce this, but, maybe, you have an idea of what can possibly go wrong there.

phridge is used only in the generateSprite function: https://github.com/w0rm/gulp-svgfallback/blob/master/index.js#L104

[jhnns]

Thx for reporting this, I'll take a look :grin:

[w0rm]

@jhnns thanks for helping out!

[ChrisZieba]

@jhnns was there ever a fix for this? I'm seeing this happen quite a bit on our end. Any info you need to help resolve?

TypeError: Cannot read property 'stdin' of null
    at Phantom._write (/var/app/current/node_modules/phridge/lib/Phantom.js:229:43)
    at /var/app/current/node_modules/phridge/lib/Phantom.js:217:14
    at new wrappedPromise (/var/app/current/node_modules/newrelic/lib/instrumentation/core/globals.js:133:18)
    at Phantom._send (/var/app/current/node_modules/phridge/lib/Phantom.js:201:12)
    at Page.run (/var/app/current/node_modules/phridge/lib/Page.js:60:25)
    at Object.server.checkIfPageIsDoneLoading (/var/app/current/node_modules/prerender/lib/server.js:289:24)
    at Timeout._repeat (/var/app/current/node_modules/prerender/lib/server.js:251:19)
    at Timeout.wrapper [as _onTimeout] (timers.js:417:11)
    at tryOnTimeout (timers.js:224:11)
    at Timer.listOnTimeout (timers.js:198:5)

I temporarily modified our module to return if not defined

Phantom.prototype._write = function (message) {
    if (!this.childProcess || !this.childProcess.stdin) return;
    this.childProcess.stdin.write(JSON.stringify(message) + os.EOL, "utf8");
};

[jhnns]

We could add this if clause, but that would just obscure the underlying problem. This callback should never been called when childProcess is null so we have to find that cause first.

Can you give some additional information? When exactly does that error happen? Can you reproduce it reliably?

[ChrisZieba]

Havent been able to reproduce since updating prerender. Might have been caused by this: https://github.com/prerender/prerender/issues/342#issuecomment-242588130

[jhnns]

Ok. I'll re-open it when you have more information :)

[Kakise]

I've got the same error on my end quite a bit. I don't know how to solve it.

https://github.com/Kakise/Blog/issues/24

If you check the travis build logs, you'll see that it is a completely random issue.