How to detect a price change?

[newbie99]

This feels like it should be something simplistic, but I can't see an obvious way to do it!

When I call listMarketBook I can get prices back, however there is no timestamp for the price, so I can't say whether the price has changed since I last refreshed.

Is there an obvious way to do this, or alternatively what approach do most people take? I presume the logical process is to create a database, then:

1) Download prices on each refresh (e.g. call listMarketBook for the desired market)
2) Compare prices from the most recent download to the previous one
3) If the change in price meets desired criteria, place bet

I would be very curious to know what approach people have taken, as it seems a bit odd to me not to include a timestamp and make this very simple (so I'm wondering if I'm just missing something really obvious)!

[LetsGo]

If you want to find out what is happening in the market you have to compare the current market book with the previous market book.
There can be many changes in price and amount available and also the total amount matched.

[newbie99]

If you want to find out what is happening in the market you have to compare the current market book with the previous market book.
There can be many changes in price and amount available and also the total amount matched.

Ah, okay yep that makes sense, I was just hoping for a simple way by timestamp (so if you haven't previously called the market book you could see there had been a recent change). But from what you're saying, it sounds like thats not possible?

[LiamP]

Just use streaming, you then know there has been a change.

[newbie99]

Just use streaming, you then know there has been a change.

Ah...I have not progressed that far yet! Will have a look at streaming....which logically does make sense now that you mention it!

[jabe]

The returned data for listMarketBook includes a version number. That might be what you want.

[newbie99]

The returned data for listMarketBook includes a version number. That might be what you want.

That's quite interesting actually, from what I can see the version doesn't update on every refresh. I'm going to presume it therefore only changes when one or more updates have occurred since the last version. If that's the case, then it could help, as I can then loop through the prices if the version is different and find any changes.

That said I still need to look into streaming, but short term, this could help (if I've understood how it works correctly)?