add subscribePosition to options and use mysql.format

[flarestart]

add a way to subscribe current binlog position

[nevill]

We should always receive rotate event when we subscribed position event. Otherwise, it sounds like a bug.

[nevill]

Thanks for your PR, can you add some tests for this feature ?

[flarestart]

Yes, I have just add a test case for this feature, plz have a look.

[numtel]

This PR is adding a new feature without explicitly stating the bug that necessitated it. In the current implementation, if a binlog event occurs that is filtered, (due to not being in the includeEvents option) there is no update to the binlogName and binlogNextPos property values.

This approach of adding another option introduces too much code to solve the problem. Instead, make those existing properties update before the filtering occurs:

if(event === undefined || event._filtered === true) return;

And then just always emit a position event, even for filtered events. The binlog_ prefix is unneeded here. Since the position and filename values are properties of the ZongJi instance object, passing these values as another object on every position update is unnecessary bloat. I recommend having no arguments for this position event. Event handlers may reference the values on the ZongJi instance.

[numtel]

Here and many other places, ==, != is used where ===, !== should be used.

[flarestart]

just like you say, '==' and '!=' is not strict. :)

[numtel]

This is some spaghetti logic. If you're testing that the position increases with each event, just do it directly.

var lastPos = null;
zongji.on('position', function() {
  lastPos !== null && test.ok(zongji.binlogNextPos <= lastPos);
  lastPos = zongji.binlogNextPos;
});

You might also want to test that there are the correct number of position events.

[flarestart]

I have a consider of check the number of position events, but I'm not sure if the binlog event is triggered as provided number.

[numtel]

What's the difference between these tests?

[numtel]

Instead of a section here, create a section just above **Options Available:** for **Events Emitted:** and take out the current text for the on method to bind handlers:

Add a listener to the binlog or error event. Each handler function accepts one argument.

[flarestart]

@numtel thanks for your comments, I'll check my code more carefully.