Jserrors generate by injected Code ?

[jedi4ever]

phantomas nodejs v0.10.7 +0ms
phantomas PhantomJS v1.9.7
phantomas phantomas v0.12.1

I was testing on a site and only got partial content and jserrors.
The page rendered ok in phantomjs screenshot but failed in phantomas.

It mentioned Type Errorsand Parse Errors. (See below)
When disabling the origConsoleLog line in the sendMsg function on scope.js , it worked.
Not sure what was happening there. But it worked :)

function sendMsg(type, data) {
  // @see https://github.com/ariya/phantomjs/wiki/API-Reference-WebPage#oncallback
  // Stability: EXPERIMENTAL - see issue #62
  /**
  if (typeof window.callPhantom === 'function') {
    window.callPhantom({type: type, data: data});
  }
  **/
 //PDB
 //origConsoleLog.call(console, 'msg:' + stringify({type: type || false, data: data || false}));
}

TRACE:
 -> /Users/patrick/dev/pusher-stats/node_modules/phantomas/core/scope.js: 124 (in function "sendMsg")
 -> /Users/patrick/dev/pusher-stats/node_modules/phantomas/core/scope.js: 136 (in function "incrMetric")
 -> phantomjs://webpage.evaluate(): 32
 -> /Users/patrick/dev/pusher-stats/node_modules/phantomas/core/scope.js: 186
 -> http://mysite.be/: 26
17:53:49.261 Event jserror emitted
17:53:49.262 TypeError: Type error
17:53:49.262 Backtrace: sendMsg(): undefined @ 124 / incrMetric(): undefined @ 136 / unknown fn: undefined @ 32 / unknown fn: undefined @ 18
6 / unknown fn: undefined @ 26 / unknown fn: undefined @ 26

[macbre]

Hi @jedi4ever,

Thanks for reporting an error. Can you log the typeof origConsoleLog before the call statement? Does this error happen on other URLs?

[jedi4ever]

@macbre it's really hard to output something there. As the console.log is used to write the output.
The run, starts with a nice typeof origConsoleLog == 'function' , and it stays a function AFAIK (doing if (typeof origConsoleLog) ) .

Do you have an idea how I can always have the good function or protect it from being changed?

[jedi4ever]

URL I'm testing is - http://eurosong.een.be/#aflevering/3

[macbre]

Chrome console for the page you've mentioned above reveals possible cause:

> console.log
function () {}

[macbre]

Works much better when run as:

phantomas --url "http://eurosong.een.be/?debug=1#aflevering/3" --verbose

The JS code that overrides the whole window.console object is that triggers the error.

[jedi4ever]

Nice spotting ; would it make sense to keep a pointer to the console.log globally at the top of the page? So it can't really get overwritten?

[macbre]

It is actually, as origConsoleLog. However, the global console object is overwritten (when there's no debug "flag" in URL), causing origConsoleLog.call(console to fail.

[macbre]

The only sensible solution I can think of is to emit more meaningful error message:

Error: phantomas: calling native console.log() failed ("TypeError: Type error")!

Modifying native objects and methods in JavaScript is asking for troubles :)