first commit.

2026-10-05 15:08:39 -03:00
commit b7799f9fff
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+<?php
+
+namespace Libs;
+
+/**
+ * PHP Proxy - DuckBrain
+ *
+ * Proxy is a library to create a PHP proxy.
+ * It allows controlling the headers that will be returned to the client,
+ * in addition to placing filters on the resulting HTML code.
+ *
+ * @author KJ
+ * @website https://kj2.me
+ * @licence MIT
+ */
+class Proxy
+{
+    public static $proxied_headers = [
+        'Set-Cookie',
+        'Content-Type',
+        'Cookie',
+        'Location',
+    ];
+    public static $proxy_base_url_canonical = '/';
+    public static $destination_host = SOURCE_URL;
+    protected static $filters = [];
+
+    /**
+     * Adds a callable (AKA filter) that will receive the content
+     * and should return a string.
+     *
+     * @param callable $cb
+     *                     Function that will modify the content.
+     *
+     * @return void
+     */
+    public static function add_filter(callable $cb): void
+    {
+        static::$filters[] = $cb;
+    }
+
+    /**
+     * Applies the filters configured with add_filter.
+     *
+     * @param string $content
+     *                        Content on which the filters will be applied.
+     *
+     * @return mixed
+     *               It would be correct to return a string, but
+     *               since the filters might not return correctly,
+     *               to avoid a design error, we specify that it returns mixed.
+     */
+    protected static function apply_filters(string $content): mixed
+    {
+        foreach (static::$filters as $filter) {
+            $content = call_user_func($filter, $content);
+        }
+        return $content;
+    }
+
+    /**
+     * Starts the proxy process.
+     *
+     * @param string|null $proxy_request_uri
+     *                                       The address to which the proxy will be applied.
+     *
+     * @return void
+     */
+    public static function run(?string $proxy_request_uri = null): void
+    {
+        // Get the URI if not defined
+        if (is_null($proxy_request_uri)) {
+            $proxy_request_uri = substr($_SERVER['REQUEST_URI'], strlen(static::$proxy_base_url_canonical));
+        } elseif (substr($proxy_request_uri, 0, 1) == '/') {
+            $proxy_request_uri = substr($proxy_request_uri, 1);
+        }
+
+        // Generate the final URL
+        $proxy_request_url = static::$destination_host . $proxy_request_uri;
+
+        // cURL initialization
+        $ch = curl_init();
+
+        curl_setopt($ch, CURLOPT_URL, $proxy_request_url);
+        curl_setopt($ch, CURLOPT_AUTOREFERER, 1);
+        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
+        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
+        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
+        curl_setopt($ch, CURLOPT_HEADER, 1);
+        curl_setopt($ch, CURLOPT_USERAGENT, $_SERVER['HTTP_USER_AGENT']);
+        curl_setopt($ch, CURLOPT_HTTPHEADER, array('Expect:'));
+        curl_setopt($ch, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_0);
+
+        // Capture client cookies
+        $hdrs = [];
+        if (isset($_SERVER['HTTP_COOKIE'])) {
+            $hdrs[] = "Cookie: " . $_SERVER['HTTP_COOKIE'];
+        }
+
+        // Capture client browser (User-Agent)
+        if (isset($_SERVER['HTTP_USER_AGENT'])) {
+            $hdrs[] = "User-Agent: " . $_SERVER['HTTP_USER_AGENT'];
+        }
+
+        // Add captured headers
+        curl_setopt($ch, CURLOPT_HTTPHEADER, $hdrs);
+
+        // Capture all client headers
+        $hdrs = [];
+        foreach (\getallheaders() as $name => $value) {
+            $hdrs[] = "$name: $value";
+        }
+
+        // Add captured headers to the request
+        curl_setopt($ch, CURLOPT_HTTPHEADER, $hdrs);
+
+        // Add POST parameters
+        if (sizeof($_POST) > 0) {
+            curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($_POST));
+        }
+
+        // Execute the request
+        $res = curl_exec($ch);
+        curl_close($ch);
+
+        // Parse the response
+        list($headers, $body) = explode("\r\n\r\n", $res, 2);
+        $headers = str_replace(static::$destination_host, '/', $headers);
+
+        $headers = explode("\r\n", $headers);
+        $hs = [];
+
+        foreach ($headers as $header) {
+            if (false !== strpos($header, ': ')) {
+                list($h, $v) = explode(': ', $header);
+                $hs[$h][] = $v;
+            } else {
+                $header1  = $header;
+            }
+        }
+
+        // Define headers in the client
+        list($proto, $code, $text) = explode(' ', $header1);
+        header($_SERVER['SERVER_PROTOCOL'] . ' ' . $code . ' ' . $text);
+
+        foreach (static::$proxied_headers as $hname) {
+            if (isset($hs[$hname])) {
+                foreach ($hs[$hname] as $v) {
+                    if ($hname === 'Set-Cookie') {
+                        header($hname . ": " . $v, false);
+                    } else {
+                        header($hname . ": " . $v);
+                    }
+                }
+            }
+        }
+
+        die(static::apply_filters($body));
+    }
+}