How to Properly Format geocodeAddresses POST with ArcGIS REST

Question

I am able to successfully process a batch geocoding request (described here geocodeAddresses—ArcGIS REST API: World Geocoding Service | ArcGIS for Developers ) using a GET request. However, I know I will want to use the POST method as the documentation describes since my batches may be large.

When I try to submit the data via POST, I get a very unhelpful error message.

{'error': {'code': 400,  
  'details': [],  
  'message': 'Unable to complete operation.'}}  

The request I am trying to make looks like this (I have tried various iterations):

URL: http://geocode.arcgis.com/arcgis/rest/services/World/GeocodeServer/geocodeAddresses?sourceCountry=USA&token=&f=pjson

POST Data (raw)

{  
    "addresses": {  
        "records": [  
            {  
                "attributes": {  
                    "OBJECTID": 1,  
                    "Address": "380 New York St.",  
                    "City": "Redlands",  
                    "Region": "CA",  
                    "Postal": "92373"  
                }  
            },  
            {  
                "attributes": {  
                    "OBJECTID": 2,  
                    "Address": "1 World Way",  
                    "City": "Los Angeles",  
                    "Region": "CA",  
                    "Postal": "90045"  
                }  
            }  
        ]  
    }  
}  

Where of course TOKEN is replaced with a valid token I have successfully tested via a GET request.

Variations I have tried included having "records" as the top level key and including the GET parameters such as the token as keys in the POST payload.

Answer 1

It turns out that ESRI wants the data to be sent as x-www-form-urlencoded, as opposed to just a JSON object. So to correctly use the endpoint, send it as formdata with the key being "addresses" and the value being the JSON records object.

Answer 2

Just to elaborate:

The Header should be Content-Type (any other specifics needed)

the Body should be x-www-form-urlencoded with the keys:

Ex.

addresses                {"records": [{"attributes": {"OBJECTID": 1,"Address": "380 New York St.","City": "Redlands","Region": "CA","Postal": "92373"}},{"attributes": {"OBJECTID": 2,"Address": "1 World Way","City": "Los Angeles","Region": "CA","Postal": "90045"}}]}   

sourceCountry                 USA

token                         

f                             pjson