I also like writing snippets in my editor, so I can step through them and do everything my IDE is capable of.
Two other techniques I have used, depending on the situation:
a) configure PHP to log it’s errors to a file, and just leave an SSH window up doing `tail -f error_log` (or whatever the path/name of your error log is) so you can watch the messages in realtime - not practical if you don’t have command-line access
b) The MODx "System Events" log (see Reports > System Events in the Manager)
MODx will automatically log some (all?) php errors from Snippets (or maybe the parser in general? I don’t know under what conditions - certain error types or notifications or what-not.. maybe look in there and see if there’s anything helpful already being logged.)
You can also log your own messages to MODx’s ’System Events’ log - I’m using this technique right now to debug a snippet on a page being called by an external web service (FoxyCart). This is impossible to step through because I’m not the one initiating the page request, and I am also unable to get php logging to a file. So I just keep logging stuff, reading the logged events and I am getting through it. Slower than I’d like, but it works ;-)
$modx->logEvent(__LINE__, 1, "subscribe ... ", '{{MailBuildSubscribe}}');
The first parameter is "event id", which is arbitrary as far as I can tell. I just set it to the line number in the snippet to make it easy to keep track of.
The second parameter is "type". This is from the in-line code documentation: Types: 1 = information, 2 = warning, 3 = error
The third parameter is "message" - any string you want to log.
The fourth parameter is "source" - again, any string you want to help you figure out the source of the log entry. (In retrospect, I may put my line number in this parameter next time, and use more meaningful event ids.)
MODX Staff