Underscore in request header in Laravel - php

Question

why laravel doesn't accept vars with underscore from request header?
I made a simple request example with a variable: "token_auth" with value 123 , but inside in my route doesn't get this value.
<?php
namespace App\Http\Controllers;
use Illuminate\Http\Request;
class Test extends Controller
{
public function teste(Request $request){
dd($request->header());
}
}
only prints header with no underscore:
array:9 [
"thisheadernounderline" => array:1 [
0 => "312321"
]
"cache-control" => array:1 [
0 => "no-cache"
]
"postman-token" => array:1 [
0 => "3c461fd1-5bea-4100-9926-81c14cb5810c"
]
"user-agent" => array:1 [
0 => "PostmanRuntime/7.1.1"
]
"accept" => array:1 [
0 => "*/*"
]
"host" => array:1 [
0 => "localhost"
]
"cookie" => array:1 [
0 => "XSRF-TOKEN=eyJpdiI6IkJwM3pjVkFBb2hxS2d4MDFcL2srM0h3PT0iLCJ2YWx1ZSI6IiszRzhoTzV0VzN5YUkydUNUTGR5aENVd291ZW01SkZ4V2ZxQkNDTGJwbDlyMFFJZGxzNnorMkF0VUNTbHpoRndLV3FmbndJWFhkXC9cL3IzOGZvN25zN3c9PSIsIm1hYyI6IjQwZWQ1YmJhM2VjM2I3N2RiNWZlYjcwYjZmYzQ0NDk5YjkwZDc4YzRjNGQwZjQxNDVkOGU1NDU0MTA0OWI2YWYifQ%3D%3D; laravel_session=eyJpdiI6IitSckpmOFI1TmpuXC9SSUt2QVY3VlFRPT0iLCJ2YWx1ZSI6IlwvVk1EaDdYdDNxRTZLNytRcnZDTlNiaVlFTWVRVmNUOHlyVnFia0pDeE9HNWpNa3QrWlBsNnNoVEduVkhrMUhkYURoNDI4cW9RdXVHU0lIS0JZN2REQT09IiwibWFjIjoiNWJmYmJmNTdmMzJkZjQ1OGQ4NTM1NjhhMzQxNDk5NWUxOTA5OGVjOThkODkyNDgwZTA2NzEyYjFlZmE2YjVjOSJ9"
]
"accept-encoding" => array:1 [
0 => "gzip, deflate"
]
"connection" => array:1 [
0 => "keep-alive"
]
]
is there any workaround to solve this?
And I cant change this because this variable comes from an API (aready asked to change but they wont wanna change).
Already tried with laravel 5.4 and laravel 5.6.
ps: with simple php works fine (no laravel framework)

Answer 1

This worked for my scenario.
I used this workaround in Laravel to solve my problem:
foreach (getallheaders() as $name => $value) {
echo "$name: $value\n";
}
output:
token_auth: 123
cache-control: no-cache
Postman-Token: f5bf7878-1f64-4ee8-907a-991d73ab8667
User-Agent: PostmanRuntime/7.1.1
Accept: */*
Host: localhost
cookie: XSRF-TOKEN=eyJpdiI6IkJwM3pjVkFBb2hxS2d4MDFcL2srM0h3PT0iLCJ2YWx1ZSI6IiszRzhoTzV0VzN5YUkydUNUTGR5aENVd291ZW01SkZ4V2ZxQkNDTGJwbDlyMFFJZGxzNnorMkF0VUNTbHpoRndLV3FmbndJWFhkXC9cL3IzOGZvN25zN3c9PSIsIm1hYyI6IjQwZWQ1YmJhM2VjM2I3N2RiNWZlYjcwYjZmYzQ0NDk5YjkwZDc4YzRjNGQwZjQxNDVkOGU1NDU0MTA0OWI2YWYifQ%3D%3D; laravel_session=eyJpdiI6IitSckpmOFI1TmpuXC9SSUt2QVY3VlFRPT0iLCJ2YWx1ZSI6IlwvVk1EaDdYdDNxRTZLNytRcnZDTlNiaVlFTWVRVmNUOHlyVnFia0pDeE9HNWpNa3QrWlBsNnNoVEduVkhrMUhkYURoNDI4cW9RdXVHU0lIS0JZN2REQT09IiwibWFjIjoiNWJmYmJmNTdmMzJkZjQ1OGQ4NTM1NjhhMzQxNDk5NWUxOTA5OGVjOThkODkyNDgwZTA2NzEyYjFlZmE2YjVjOSJ9
accept-encoding: gzip, deflate
Connection: keep-alive