How do I read data from EventSub callbacks?

[lancemcdonald]

When EventSub hits my callback webhook, the POST, GET, and Headers don’t have the challenge info in them. Where is it stored?

I used PHP to getallheaders(), print_r($_POST) and print_r($_GET) when EventSub sends me a challenge but this is all the data that’s in the request from Twitch.

Headers: Array
(
[Host] => [redacted]
[Connection] => Keep-Alive
[Accept-Encoding] => gzip
[CF-IPCountry] => US
[X-Forwarded-For] => 54.184.54.118
[CF-RAY] => [redacted]
[Content-Length] => 387
[X-Forwarded-Proto] => https
[CF-Visitor] => {“scheme”:“https”}
[User-Agent] => Go-http-client/1.1
[Content-Type] => application/json
[Twitch-Eventsub-Message-Id] => ef689031-7181-4ce2-af19-0743cd05ee13
[Twitch-Eventsub-Message-Retry] => 0
[Twitch-Eventsub-Message-Signature] => sha256=ce4aadf48861a3e29fd65f39873136d65b159f1533e7d5d3cca13bd97289b104
[Twitch-Eventsub-Message-Timestamp] => 2020-12-19T06:20:40Z
[Twitch-Eventsub-Message-Type] => webhook_callback_verification
[Twitch-Eventsub-Subscription-Type] => channel.follow
[Twitch-Eventsub-Subscription-Version] => 1
[CF-Request-ID] => 071b41661400003a029e9d0000000001
[CF-Connecting-IP] => 54.184.54.118
[CDN-Loop] => cloudflare
[X-HTTPS] => 1
)
$_POST Array
(
)
$_GET Array
(
)

[lancemcdonald]

Okay I figured it out, I didn’t realize you need to do some silly stuff to get PHP to read headers from content-type json.

The solution was to use this code:
$json = file_get_contents(‘php://input’);
$myPostData .= print_r(json_decode($json, TRUE),true);
This creates an ugly string called $myPostData with the info in it. Hopefully this info helps someone else some day.

[BarryCarlyon]

Yeah that is the correct way to read “incoming body data” in PHP

As Webhooks/Eventsub/PayPay IPN/other kinds of webhooks, they send a POST request but they don’t send POST data, so you have to read php://input

Related post on the subject

https://lornajane.net/posts/2017/handling-incoming-webhooks-in-php
https://lornajane.net/posts/2008/accessing-incoming-put-data-from-php

If you were building an API you’d have the same “fun” with PUT requests via cURL