Add timeout to remaining HTTP requests (#316)

Prevent get_headers() and file_get_contents() from hanging indefinitely.

Changes:
- Utility::urlExists() fallback: Add stream context with 5s timeout
- Utility::getHeaderFromUrl(): Add 5s timeout to stream context defaults
- Mime::getMimeTypeByUrl(): Add stream context with 5s timeout
- Message::_readFile(): Add 10s timeout (files may be larger)

Author: dereuromark

src/Mailer/Message.php

@@ -398,9 +398,12 @@ protected function _getMime($filename, $default = 'application/octet-stream') {
 	 * @return string File contents in base64 encoding
 	 */
 	protected function _readFile($path) {
-		$context = stream_context_create(
-			['http' => ['header' => 'Connection: close']],
-		);
+		$context = stream_context_create([
+			'http' => [
+				'timeout' => 10,
+				'header' => 'Connection: close',
+			],
+		]);
 		$content = file_get_contents($path, false, $context);
 		if (!$content) {
 			throw new RuntimeException('No content found for ' . $path);

src/Utility/Mime.php

@@ -794,8 +794,13 @@ public static function _detectMimeType($file) {
 		// Treat non local files differently
 		$pattern = '~^https?://~i';
 		if (preg_match($pattern, $file)) {
+			$context = stream_context_create([
+				'http' => [
+					'timeout' => 5,
+				],
+			]);
 			// phpcs:disable
-			$headers = @get_headers($file);
+			$headers = @get_headers($file, false, $context);
 			// phpcs:enable
 			if (!$headers || !preg_match("|\b200\b|", $headers[0])) {
 				return '';

src/Utility/Utility.php

@@ -307,8 +307,13 @@ public static function urlExists($url, array $statusCodes = []): bool {
 			return in_array($statusCode, $statusCodes, true);
 		}
 
+		$context = stream_context_create([
+			'http' => [
+				'timeout' => 5,
+			],
+		]);
 		// phpcs:disable
-		$headers = @get_headers($url);
+		$headers = @get_headers($url, false, $context);
 		// phpcs:enable
 		if ($headers && preg_match('|\b200\b|', $headers[0])) {
 			return true;
@@ -346,6 +351,7 @@ public static function getHeaderFromUrl(string $url) {
 
 		$defaults = [
 			'http' => [
+				'timeout' => 5,
 				'header' => "Accept: text/html\r\n"
 					. "Connection: Close\r\n"
 					. "User-Agent: Mozilla/5.0 (Windows NT 6.2; WOW64)\r\n",