Getting a JSON response with requests and ArcGIS REST API

Question

I'm performing a batch download from my AGOL account, and using the ESRI documentation export item I can export content to shapefiles. I would like to then download the newly created shapefiles. In order to accomplish this I have to be able to have the ID number of the newly created shapefile. According to the documentation it is in the JSON response.

sudo code:

import requests
import arcrest
import json

exporturl = self.root_url +'/users/' + self.username + '/export'
export = requests.post(exporturl, params=FsParams)
export_response = export.json()

What I have tried:

response = export_response['exportItemId']
print response

Error: KeyError: 'exportItemId'

printing response = export_response returns the params from the post

Using the requests library can I access the JSON response? If this is not possible with requests what method will work?

Answer 1

The code, as posted, is correct when working with requests and json. As indicated from the comments, when making a request over multiple items, you might get a different response back depending on what the original item was requested against.

The error in question, KeyError: 'exportItemId' comes from the fact the response returned a dictionary without the exportItemId key and you tried to access it. There are multiple ways to handle this. A simple try / except as you indicate will allow you to pass over instances when you dont get back a key which you were expecting. Alternatively you could do an explicit check that the key exists in the dictionary before attempting to access it.