Step 57 – Error Codes

The SCORM 1.2 Runtime Environment (RTE) uses a system of error codes that are set by the API, and which can be read by the SCO using three API functions:

• LMSGetLastError()
• LMSGetErrorString()
• LMSGetDiagnostic()

I’ve already implemented “stubs” for these functions in my api.php code as noted in Step 10 – Other SCORM API Fuctions. But, before I make these functions active, I need to set up the error codes and related messages in the API code.

The error codes are all detailed in the SCORM 1.2 Runtime Environment specification – section 3.3.3. So, I’m going to set up a JavaScript object (which,having been brought up on perl and PHP, I tend to think of as an ‘associative array’) in the api.php code:

var errorMessages = new Object();
errorMessages['0'] = 'No Error';
errorMessages['101'] = 'General Exception';
errorMessages['201'] = 'Invalid Argument';
errorMessages['202'] = 'Element Cannot Have Children';
errorMessages['203'] = 'Element Not an Array - Cannot Have Children';
errorMessages['301'] = 'API Not Initialized';
errorMessages['401'] = 'Data Model Element Not Implemented';
errorMessages['402'] = 'Invalid Set Value - Element is a Keyword';
errorMessages['403'] = 'Invalid Set Value - Element is Read Only';
errorMessages['404'] = 'Invalid Get Value - Element is Write Only';
errorMessages['405'] = 'Invalid Set Value - Incorrect Data Type';

Why am I using strings e.g. ‘201’ rather than numbers as indices? Because it’s one of the (many) idiosyncrasies of the SCORM standard!

Next time, setting and storing the error code.