cURL request getting wrong request version in Google App Engine - php

Question

I have a cURL request in my code which works fine when running locally:
$url = "http://ipinfo.io/{$_SERVER['REMOTE_ADDR']}";
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_TIMEOUT, 10);
$response = curl_exec($ch);
$locale = json_decode($response);
and returns a JSON as expected. Our production system is on Google App Engine, however, where I get the website version for a browser rather than the JSON.
I can get this cURL request to work if I change
google_app_engine.enable_curl_lite = "1"
in the php.ini in the root directory of my project to
extension = "curl.so"
but Google's documentation insists the former is to be used on production. Additionally, using the latter breaks things like Monolog's SlackHandler.
Is there a way to get the JSON from this cURL request while still using Google's "cURL Lite"?

Answer 1

From the ipinfo.io documentation:
"We do a little bit of magic on the server to determine if we should send the JSON response or the webpage. We usually get it right, but if you're seeing the webpage instead of the JSON (or want to check the JSON output in a browser) you can force the JSON response by adding /json to the end of the URL"
Adding /json to the end of the URL worked for me in this case, but I wanted a more general solution. Since Google's cURL Lite uses their URL Fetch in the background, ipinfo.io's "magic" is somehow getting confused. I found that by specifying the Accept header then the /json addition wasn't required. In PHP:
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Accept: application/json'));
Thanks to the folks on the #php channel of NashDev Slack for helping me on this one!