http-requests-test.php

<?php

$errno = 0;
$errstr = '';

$fp = fsockopen('165.227.126.241', 80, $errno, $errstr, 30);

if (!$fp) {
    echo $errstr .'('. $errno . ')';
} else {
    $out = "GET /ws/{put-cep-here}/json/ HTTP/1.1\r\n";
    $out .= "Host: viacep.com.br\r\n";
    $out .= "Connection: Close\r\n\r\n";

    fwrite($fp, $out);

    while (!feof($fp)) {
        echo fgets($fp, 128);
    }

    fclose($fp);
}

/*
$ dig viacep.com.br +short
165.227.126.241

$ php -f http-request-test.php
HTTP/1.1 200 OK
Server: nginx/1.22.0
Date: Thu, 28 Sep 2023 18:47:42 GMT
Content-Type: application/json; charset=utf-8
Transfer-Encoding: chunked
Connection: close
Expires: Thu, 28 Sep 2023 19:47:42 GMT
Cache-Control: max-age=3600
Pragma: public
Cache-Control: public
Access-Control-Allow-Origin: *
Access-Control-Allow-Methods: GET
Access-Control-Allow-Headers: Content-Type, X-Request-With, X-Requested-By
Access-Control-Allow-Credentials: true
Access-Control-Max-Age: 86400

db
{
  "cep": "...",
  "logradouro": "...",
  "complemento": "",
  "bairro": "...",
  "localidade": "...",
  "uf": "...",
  "ibge": "...",
  "gia": "",
  "ddd": "...",
  "siafi": "..."
}
0

*/

http-requests.php

<?php

/**
 * fsockopen(string $hostname,[ int $port = -1 [, int &$errno [, string &$errstr [, float $timeout = ini_get("default_socket_timeout") ]]]])
 * @see: http://php.net/manual/en/function.fsockopen.php
 * @see: https://github.com/aligent/jirafe-magento-plugin/blob/master/app/code/community/Fooman/Jirafe/Model/JirafeTracker.php
 */

/**
 * NOT TESTED BY ME YET!
 *
 * HTTP Request with fsockopen
 * This can be used as async, because it doesn't wait to get a response
 */

$fp = fsockopen("www.example.com", 80, $errno, $errstr, 30);
if (!$fp) {
    echo "$errstr ($errno)<br />\n";
} else {
    $out = "GET / HTTP/1.1\r\n";
    $out .= "Host: www.example.com\r\n";
    $out .= "Connection: Close\r\n\r\n";
    fwrite($fp, $out);
    while (!feof($fp)) {
        echo fgets($fp, 128);
    }
    fclose($fp);
}

/**
 * NOT TESTED BY ME YET!
 *
 * HTTPS Request with fsockopen
 * This can be used as async, because it doesn't wait to get a response
 */

$fp = fsockopen("ssl://www.example.com", 443, $errno, $errstr, 30);
if (!$fp) {
    echo "$errstr ($errno)<br />\n";
} else {
    $out = "GET / HTTP/1.1\r\n";
    $out .= "Host: www.example.com\r\n";
    $out .= "Connection: Close\r\n\r\n";
    fwrite($fp, $out);
    while (!feof($fp)) {
        echo fgets($fp, 128);
    }
    fclose($fp);
}