Error handler module

[Gloorf]

Currently, this only works with nashorn

• Can pretty print an exception :

  • display the message (with color !)
  • display the function name (with color !) See later for explanation
  • Remove unwanted stack lines, by filtering on filename : by default, only display stack line located in scriptcraft/players : each player will only see the stack lines in his files

• Exports eventWrapper : a decorator intended for events (registered via events.*), catching exceptions and pretty printing them to relevant player(s)

• Exports functionWrapper : decorator intended for function, catching exceptions and pretty printing them to the function caller

• Direct integration with scriptcraft __onCommand : catch all exception generated by /js command, and pretty print (instead of simply displaying the exception message)

Finding the function name

Nashorn doesn't make it easy for us : it doesn't give the methodName for JS code, only the filename + line number. So i can't get the function name with only the stack.

Fortunately, __onCommand uses nashorn load function (see doc), which has a neat feature : you can pass a 'name', which will be displayed in the stack trace. Specifically, it's displayed on the stack frame corresponding to the __onCommand call, which is identified by the 'methodName' beeing ''.

We still need to find the function name, when __onCommand is called. To do this, I've opted for inline comments (like shout module), of the form "#f:fnName". The clickable chat module automatically adds them to the command (I recommend using that !).

Some example screenshots

Wrapped event

The code is the following :

var eventWrapper = require("error-handler").eventWrapper;
events.playerAnimation(eventWrapper(function(event) {
    echo(event.player, "playerAnimationEvent");
    event.player.invalidMethod();
}));

java exception

Note : this is a regular function, the exception is catched by the direct integration with __onCommand

javascript exception

Note : this is a regular function, the exception is catched by the direct integration with __onCommand

javascript exception (without function name comment)

Note : this is a regular function, the exception is catched by the direct integration with __onCommand

/js command exception