Updated version to properly create array of data

fetch.py

@@ -9,34 +9,80 @@
 #
 # Use:
 #	import fetch
-#	fetch.sensor_pull_storage(...)
+#	fetch.sensor_pull_storage(...) -- see docs for args
 #
 #	Or just cut/paste into your script.
 #
 
 import subprocess
+import json
+import pathlib
+import re
 
-def sensor_pull_storage(accesskey, timestring, appname, data_folder):
+class Error(Exception):
+	"""Base class for errors in this module"""
+	pass
+
+class FetchError(Error):
+	"""Raised when sensor_pull_storage can't deal with input
+
+	Atrributes:
+	   expression -- input expression where error occurred
+	   message -- explanation of the error.
+	"""
+	def __init__(self, expression, message):
+		self.expression = expression
+		self.message = message
+
+def sensor_pull_storage(appname, accesskey, timestring, *,data_folder = None, ttn_version=3):
 	"""
 	Pull data from TTN via the storage API.
 
-	accesskey is the full accesskey from ttn, starting with 'ttn-acount-v2.'
-	timestring indicates amount of data needed, e.g. '1d'.
 	appname is the name of the TTN app
-	data_folder, if not None, says where to put the data.
+
+	accesskey is the full accesskey from ttn.  For TTN V3, this is is the
+		secret output when a kye is created. For TTN V2, this is
+		the string from the console, starting with 'ttn-acount-v2.'
+
+	timestring indicates amount of data needed, e.g. '1d'.
+
+	ttn_version should be 2 or 3; 3 is default.
+
+	If data_folder is supplied, it is a string or a Path; the name "
+	The data is returned as a string. Use json.loads() to decode into an object.
 	"""
-	args = 	[ "curl",
-		  "-X", "GET",
-		  "--header", "Accept: application/json",
-		  "--header", f"Authorization: key {accesskey}",
-		  f"https://{appname}.data.thethingsnetwork.org/api/v2/query?last={timestring}"
+	args = [ "curl" ]
+	if ttn_version == 2:
+		args += [
+			"-X", "GET",
+			"--header", "Accept: application/json",
+			"--header", f"Authorization: key {accesskey}",
+			f"https://{appname}.data.thethingsnetwork.org/api/v2/query?last={timestring}"
+			]
+	elif ttn_version == 3:
+		args += [
+			"-G", f"https://nam1.cloud.thethings.network/api/v3/as/applications/{appname}/packages/storage/uplink_message",
+			"--header", f"Authorization: Bearer {accesskey}",
+			"--header", "Accept: text/event-stream",
+			"-d", f"last={timestring}",
+			"-d", "field_mask=up.uplink_message.decoded_payload",
 		]
+	else:
+		raise FetchError(f"Illegal ttn_version (not 2 or 3)")
+
 
 	# if the user supplied a data_folder, than tack on the args.
 	# list1 += list2 syntax means "append each element of list2 to list 1"
+	# pathlib.Path allows 
 	if data_folder != None:
-		args += [ "-o", f"{data_folder}sensors_lastperiod.json"]
+		args += [ "-o", pathlib.Path(data_folder, "sensors_lastperiod.json") ]
 
-	return subprocess.run( 
-		args, shell=False
+	result = subprocess.run( 
+		args, shell=False, check=True, capture_output=True
 		)
+
+	sresult = result.stdout
+	if ttn_version == 3:
+		return list(map(json.loads, re.sub(r'\n+', '\n', sresult.decode()).splitlines()))
+	else:
+		return sresult