Add gemini:// support for file_get_contents(). Will turn into proper repo with Composer support later.

GeminiStreamWrapper.php

<?php declare(strict_types=1);

namespace Zegnat\Gemini;

/**
 * @see https://www.php.net/manual/en/class.streamwrapper.php
 */
final class GeminiStreamWrapper {
    /** @var resource $context if a stream context was provided it will be set here, even before __construct */
    public $context;

    /** @var resource $connection if a stream was successfully opened, this holds the pointer to the TLS stream */
    private $connection;

    private function __construct()
    {
    }

    /**
     * First thing to implement! Create connection.
     * 
     * The STREAM_REPORT_ERRORS option is ignored, if something goes wrong trigger_error is always called.
     * The STREAM_USE_PATH option is also ignored, gemini:// paths will always be absolute to trigger this wrapper.
     * Because STREAM_USE_PATH is ignored, $opened_path is never assigned.
     */
    public function stream_open(string $path, string $mode, int $options, string &$opened_path = null): bool {
        // Made to match the HTTP wrapper (which for some reason allows c mode for reading)
        if (($mode[0] !== 'r' && $mode[0] !== 'c') || \strchr($mode, '+') !== false) {
            \trigger_error('fopen(' . $path . '): Failed to open stream: Gemini wrapper does not support writeable connections', \E_USER_WARNING);
            return false;
        }

        $host = \parse_url($path, \PHP_URL_HOST);
        $port = \parse_url($path, \PHP_URL_PORT) ?: 1965;
        if (!is_string($host) || !is_int($port)) {
            \trigger_error('fopen(' . $path . '): Failed to open stream: Provided path lacks a usable host/port', \E_USER_WARNING);
            return false;
        }
        if (mb_strlen($path, '8bit') > 1024) {
            \trigger_error('fopen(' . $path . '): Failed to open stream: Provided path cannot be bigger than 1024 bytes', \E_USER_WARNING);
            return false;
        }

        // The TLS connection settings.
        $context = \stream_context_create(['ssl' => [
            'allow_self_signed' => true,
        ]]);

        // C: Opens connection
        // C: Validates server certificate
        $this->connection = \stream_socket_client('tls://' . $host . ':' . $port, context: $context);
        if ($this->connection === false) {
            \trigger_error('fopen(' . $path . '): Failed to open stream: Socket could not be opened', \E_USER_WARNING);
            return false;
        }

        // C: Sends request (one CRLF terminated line)
        $writeSuccess = \fwrite($this->connection, $path . "\r\n");
        if (false === $writeSuccess) {
            $this->stream_close();
            \trigger_error('fopen(' . $path . '): Failed to open stream: Request could not be send to the server', \E_USER_WARNING);
            return false;
        }

        // Receive response header (one CRLF terminated line)
        $header = \fgets($this->connection, 2 + 1 + 1024 + 2);

        // If a server sends a <STATUS> which is not a two-digit number or a <META> which exceeds 1024 bytes in length, the client SHOULD close the connection and disregard the response header, informing the user of an error.
        if (false === $header || \preg_match("/^\d\d\x20.{0,1024}\r\n$/", $header) !== 1) {
            $this->stream_close();
            \trigger_error('fopen(' . $path . '): Server returned an invalid response header', \E_USER_WARNING);
            return false;
        }

        return true;
    }

    public function stream_read(int $count): string {
        return \fread($this->connection, $count);
    }

    public function stream_eof(): bool {
        return \feof($this->connection);
    }

    public function stream_close(): void {
        \fclose($this->connection);
    }

    /**
     * fstat is not supported for remote files, as per standard PHP.
     * @see https://www.php.net/manual/en/function.fstat.php
     */
    public function stream_stat(): bool {
        return false;
    }
}

if (!stream_wrapper_register('gemini', GeminiStreamWrapper::class, \STREAM_IS_URL)) {
    throw new \RuntimeException('Could not register the Gemini streamWrapper.');
}