Why would Oraclize fail when a normal post doesn't?

Question

I'm using the Oraclize test query to confirm my oraclize response is empty. Here's a link to the exact test query, which contains the following:

URL  ["json(https://mainnet.infura.io/).result","{"jsonrpc":"2.0","id":1,"method":"eth_blockNumber","params":[]}"]
_

When this same endpoint is queried with the same POST params from Postman like here I get a correct response.

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x421283"
}

Why does Oraclize return an empty response instead?

Answer 1

I got a reply from an Oraclize developer on their github that can be seen here. He says when using the second parameter as a POST payload a whitespace needs to be included at the beginning or end of the JSON object. Here is his updated version of my query returning a correct result 🎉