ArcPy Get Coded Domain Values from Portal/AGOL

[JimHerberich]

I am retrieving data from Feature Service Feature Class and Feature Service Table sources hosted on Portal (10.6) via a Python toolbox tool in ArcGIS Pro (currently 2.2.1).  Some fields have coded domains, and naturally I want to return the domain values instead of the codes.  I thought I could use arcpy.da.ListDomains or arcpy.DomainToTable_management to enable the lookups, except I can't find what to use as the "in_workspace" parameter for these (the service URL does not work).  Currently fetching data with arcpy.da.TableToNumPyArray but could go to arcpy.da.SearchCursor although that returns codes, too.  Am I out-of-luck?

[RandyBurton]

You can use the REST API to read the feature layer's JSON.  You can find the domain information listed in the fields section.  For AGOL I have used this code (with modification, it may also work with Portal).  It returns a field's domain in an ordered dictionary.  From there, you can get the domain's name, type and the name/code pairing.  Hope this helps.

import urllib
import urllib2
import json
import collections

# Credentials and feature service information
username = <username>
password = <password>

services = [ "FeatureLayerName" ] # service you are interested in
URL = "https://services.arcgis.com/<abcxyz>/arcgis/rest/services/" # modify as needed


# obtain a token
referer = "http://www.arcgis.com/"
query_dict = { 'username': username, 'password': password, 'referer': referer }

query_string = urllib.urlencode(query_dict)
url = "https://www.arcgis.com/sharing/rest/generateToken"
token = json.loads(urllib.urlopen(url + "?f=json", query_string).read())

if "token" not in token:
    print(token['error'])
    sys.exit(1)

query_dict = { "f": "json", "token": token['token'] }

# display json data
for service in services:

    # print service + " - ",
    fsURL = URL + service + "/FeatureServer/0" # assumes first layer, may need to adjust

    jsonResponse = urllib.urlopen(fsURL, urllib.urlencode(query_dict))

    jsonOutput = json.loads(jsonResponse.read(),
                            object_pairs_hook=collections.OrderedDict)[u'fields']

    for field in jsonOutput:
        if field["domain"] is not None:
            print field["domain"]
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EDIT -  Also, when you query a feature with the REST API, the returned JSON includes a fields section with a features (attributes) section.  You just need to process the fields section for domains and then process the features/attributes.

[JimHerberich]

Thanks Randy.  But completely separate access method and authentication method don't really help in the Desktop (arcpy) context... at least we now know where to get the info!