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Can ESI determine number of orders from a structure?

First post
Author
Pandemic Horde
#1 - 2017-05-13 11:35:52 UTC
Hi,

Apart from determining the lowest sell prices, I want to use ESI to also see number of orders in a particular structure(consider it to be a citadel).

Now, if for Item X, if I count number of unique sell orders, I often get very wrong numbers. Like if ESI tells me Item X has 5 order IDs, but when I check in game client, I may actually have say 15 sell orders from sell structure, which really means the item is v.v. competitive and I dont want to go through the hassle competing with so many guys.

Anyway to fix/work around that?


Is my logic wrong? or is it possible I'm not capturing entire data? I feel it might have to do with pages 1,2,3 etc , as I took only page 1, but just want to double check the logic of counting unique order_id's to determine number of sellers etc.
Gallente Federation
#2 - 2017-05-13 12:03:49 UTC  |  Edited by: salacious necrosis
You're on the right track, but there are a few things to be aware of:


  1. You definitely need to capture all pages, particularly in busy markets. You'll miss orders otherwise.
  2. ESI orders are cached for five minutes. Therefore, it's common for the in-game client and ESI to be out of sync periodically.
  3. Order count is at best an upper bound on the number of participants since a single participant could have multiple orders.
  4. I've found two good ways to gauge competitiveness: 1) check how often the "top of book" changes, which is the current best bid and ask; and 2) check how often individual orders change, which you can check by keeping track of orders and their prices.


I'm in the middle of writing on this topic for my book. I cover this topic in my chapter on market making (aka station trading) which I'm still writing. If you want a sneak peak at the part where I cover this topic, see "Example 13 - Detecting Market Making".

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#3 - 2017-05-13 17:06:45 UTC
An important thing is to make sure you use the authenticated market endpoint for the structure.

https://esi.tech.ccp.is/latest/#!/Market/get_markets_structures_structure_id

If you don't, you won't see anything but ranged buy orders from that structure. As Salacious says, you may need to check multiple pages. iirc, it'll return 10k orders (it may only be 100 orders. I think that got updated, but can't say for sure)

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Pandemic Horde
#4 - 2017-05-13 19:37:24 UTC
hi guys,

multiple pages fixed it. I was only capturing page 1 previously.

o/

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