How to tell on FeatureLayers (or MapService/FeatureService), when the underlying data was last updated?

[CateUselton]

I'm trying to figure out how I can tell, looking at the metadata on a FeatureLayer (or a FeatureServer or MapServer), how recently the data for that asset has changed, like an "updated_at" field.

I know some FeatureLayers after version 10 have an "editFieldsInfo" with a possible "editDateField" that can indicate the last time a particular feature changed, but is there anything else that can indicate that on the asset as a whole?

[RandyBurton · Accepted solution]

The json file that describes your feature has the "last edit date" as a UTC timestamp (assuming AGOL).  The time is the date/time of the last item added to the feature/table  OR when its definition was last changed/updated.

  "editingInfo" : {
    "lastEditDate" : 1528926651042
  }, 
‍‍‍

If edit tracking is enabled, you can query the feature/table's "EditDate" field for the most recent update.

[RandyBurton]

Here's an old python script to get the "lastEditDate" of a feature from AGOL: Obtain last edit date from REST API using Python

As I mentioned previously, I will also query the layer/table for the "EditDate" field (when edit tracking is enabled).  If the layer definition was updated (adding/modifying a domain, for example), then lastEditDate would reflect these updates, even if it has been some time since a feature was added to the layer.

[CateUselton]

Thank you Randy, that was really helpful! I was able to find a little more documentation about it on the documentation page as well: Layer (Feature Service)—ArcGIS REST API: Services Directory | ArcGIS for Developers  (search 'editingInfo'). This is exactly the sort of field I was looking for.

Do you know if there is any backup field I can use, for cases when the 'editingInfo' is not provided?

[RandyBurton]

I have always found lastEditDate to be in the json file and a reliable method of knowing when updates have occured.  I have only on a few rare occasions found this value to be None; however, it would quickly become a date once a record was added or edited.  The only backup I could suggest would be with editor tracking and examine the EditDate field.  My experience has been with AGOL.  I assume server/portal would be much the same.