json - How to send the content of SSL-related files to the API call | PHP | cUrl

I have two files for SSL ssl_crt and ssl_key. I want to read the content of these files and send it to the APIs as a JSON field. But the file_get_contents actually convert the single slash to double so the API return the following error.

The private key format is invalid.

The certificate format is invalid.

I am actually using run cloud service where I want to send the content of these files to one of their API

https://runcloud.io/docs/api/web-application#ssl-basic-install-ssl

As you can see in the above URL, they need the content in the proper format.

So I tried the following.

$curl = curl_init();

$ssl_crt = file_get_contents(selectServer()->ssl_crt_path);
$ssl_key = file_get_contents(selectServer()->ssl_key_path);

$data = [
    'provider' => 'custom',
    'enableHttp' => true,
    'enableHsts' => false,
    'certificate' => $ssl_crt,
    'privateKey' => $ssl_key,
];

curl_setopt_array($curl, array(
    CURLOPT_URL => 'https://manage.runcloud.io/api/v2/servers/{id}/webapps/{webapp_id}/ssl',
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_ENCODING => '',
    CURLOPT_MAXREDIRS => 10,
    CURLOPT_TIMEOUT => 0,
    CURLOPT_FOLLOWLOCATION => true,
    CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
    CURLOPT_CUSTOMREQUEST => 'POST',
    CURLOPT_POSTFIELDS => json_encode($data, JSON_UNESCAPED_SLASHES),
    CURLOPT_HTTPHEADER => array(
        'Accept: application/json',
        'Content-Type: application/json',
        'Authorization: Basic {token}'
    ),
));

$response = curl_exec($curl);

curl_close($curl);
echo $response;

If I manually write the content of the certificate(or key) to the data array then it works fine. i.e

$data = [
    // ...
    'certificate' => '-----BEGIN CERTIFICATE-----\nblah\nblah==\n-----END CERTIFICATE-----,
    'privateKey' => '-----BEGIN PRIVATE KEY-----\nblah\nblah==\n-----END PRIVATE KEY-----,
];

The actual issue with the format. the "\n" becomes "\n" and the main content of the certificate or key can have "\n".

Can someone help me out with this?

Solution:

the post-mortem here is that the on-disk file was corrupted, the on-disk file had all newlines converted to literal-slash-followed-by-n, which PHP's double-quote operator was fixing, thus it worked when you hardcoded the file (with php's double-quote operator. it would not have worked with php's single-quote operator), and didn't work when you got it from file_get_contents() - code used to fix the on-disk file was

<?php
$real_crt=file_get_contents("ssl_crt");
$fixed_crt = strtr($real_crt,array(
    "\\n"=>"\n",
    "\\r"=>"\r",
));
file_put_contents("ssl_crt_fixed",$fixed_crt);

i only figured this out after you sent me the ssl_cert file on facebook messenger, though, and i'm pretty sure the ssl_cert file was required to solve this mystery, so i have voted to close this question as requires the shortest code necessary to reproduce the problem. ie, it needs the ssl_cert file to be any kind of reproducible