PHP - curl localhost connection refused - php

Question

Explanation
I made a simple REST api in Java (GET).
Postman works (both localhost and IPv4)
curl from command line works (both localhost and IPv4)
External request from a different city works (IPv4)
Expected
To have PHP curl work on the localhost
Actual
For some reason PHP curl on IPv4 works, but localhost does not work
PHP curl output error
Failed to connect to localhost port 8080: Connection refused
curl error: 7
Code
$url = 'http://localhost:8080/api/user';
$curl = curl_init($url);
echo json_decode(curl_exec($curl));
I have tried (from the top of my head, no specific order)
curl_setopt ($curl, CURLOPT_PORT , 8080);
curl_setopt($curl, CURLOPT_POST, false);
curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);

Answer 1

For those ones who are using Docker, Vargant and so on.
You got Failed to connect to localhost port 8080: Connection refused error, because you are trying to connect to localhost:8080 from inside virtual machine (eq. Docker), this host isn't available inside the Docker container, so you should add a proxy that can reach a port from the out.
To fix this issue add the next line of code after your curl_init():
curl_setopt($ch, CURLOPT_PROXY, $_SERVER['SERVER_ADDR'] . ':' . $_SERVER['SERVER_PORT']);
Here is a full example:
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $APIUrl);
if ($_SERVER['HTTP_HOST'] == 'localhost:8080') {
// Proxy for Docker
curl_setopt($ch, CURLOPT_PROXY, $_SERVER['SERVER_ADDR'] . ':' . $_SERVER['SERVER_PORT']);
}
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$response = curl_exec($ch);
if (curl_errno($ch)) {
$error = curl_error($ch);
}
curl_close($ch);

Answer 2

I'm not sure if this counts as an answer but I just restarted the linux VM and now its working...

Answer 3

Not sure if it's still usefull for you, but I've faced with almost same problem. I've started php server using php -S localhost:5500 or with VS-code extention, and try to connect via curl to same host, and it taken almost infinite time with no response. Solution was simple (if you understand russian, or can use translator you can find full article here).
So, from this article:
This script will not work with the default WPN-XM v0.8.6 setting because there is only one php -C gi process listening in the background, but your example requires (at least) two of them. php -C gi is already in use by the script making the curl request and therefore Nginx cannot redirect it to php -C gi. This means that you will first come across a blank page with a loading indicator and then remove the connection timeout.
The main problem is that php -C gi doesn't automatically spawn new processes (if needed). The issue is discussed here: https://github.com/WPN-XM/WPN-XM/issues/323
So the solution for me was to create another php server with a different port (for example 5500 and 5550) and everything started working.