From 0fc7deecbeed58bc99c94a1e0b89ac51f006a163 Mon Sep 17 00:00:00 2001
From: Mischa POSLAWSKY <perl@shiar.org>
Date: Fri, 9 Jul 2021 02:49:21 +0200
Subject: [PATCH] mail: decode multipart attachments (text, html, images)

---
 mail/index.php | 64 ++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 54 insertions(+), 10 deletions(-)

diff --git a/mail/index.php b/mail/index.php
index ee7365a..9f57064 100644
--- a/mail/index.php
+++ b/mail/index.php
@@ -36,21 +36,65 @@ if ($msgid) {
 	);
 	print '</dl>';
 
-	if (preg_match('{^text/plain}', $head['Content-Type'] ?? 'text/plain')) {
+	$type = preg_replace('/;.*/', '', $head['Content-Type'] ?? 'text/plain', 1);
+	switch ($type) {
+	case 'text/plain':
 		$body = $rawbody;
 		if (($head['Content-Transfer-Encoding'] ?? '') === 'quoted-printable') {
 			$body = quoted_printable_decode($body);
 		}
-		printf('<pre>%s</pre>', htmlspecialchars($body));
-	}
-	else {
-		printf('<p>Geen ondersteuning voor <em>%s</em>.</p>', htmlspecialchars($head['Content-Type']));
-
-		/* TODO
+		$body = nl2br(htmlspecialchars($body));
+		print "<p>$body</p>\n";
+		break;
+	case 'multipart/alternative':
 		$mime = mailparse_msg_parse_file($filename);
-		$part = mailparse_msg_get_part($mime, '1');
-		mailparse_msg_extract_part_file($part, $filename);
-		*/
+		foreach (mailparse_msg_get_structure($mime) as $section) {
+			print "<h3>$section</h3>\n";
+			$part = mailparse_msg_get_part($mime, $section);
+			if ($section === '1') {
+				continue; // do not access container to prevent segfault
+			}
+			$pinfo = mailparse_msg_get_part_data($part);
+		#printf('<pre>%s</pre>', htmlspecialchars(print_r($pinfo,TRUE)));
+			$phead = $pinfo['headers'];
+			list ($ptype) = explode(';', strtolower($phead['content-type']));
+			list ($pmedia) = explode('/', $ptype);
+			switch ($pmedia) {
+			case 'multipart':
+				continue 2;
+			case 'text':
+				$body = mailparse_msg_extract_part_file($part, $filename, NULL);
+				#iconv($pinfo['charset'], 'UTF-8', $body); #TODO test if needed
+				switch ($ptype) {
+				case 'text/plain':
+					$body = htmlspecialchars($body);
+					print "<pre><p>$body</p></pre>\n";
+					break;
+				case 'text/html':
+					$body = preg_replace('{
+						(<br */?>) | <[^>]+> # keep line breaks, replace other elements
+					}x', "\\1\n", $body); # strip_tags
+					print "<p>$body</p>\n";
+					break;
+				}
+				break;
+			case 'image':
+				if (!preg_match('/^inline;/', $phead['content-disposition'])) {
+					continue 2;
+				}
+				$name = iconv_mime_decode($phead['disposition-filename']);
+				$body = mailparse_msg_extract_part_file($part, $filename, NULL);
+				printf('<img src="data:%s;base64,%s" alt="%s" />',
+					$ptype, base64_encode($body),
+					htmlspecialchars($phead['name'] ?? '-')
+				);
+				break;
+			}
+		}
+		mailparse_msg_free($mime);
+		break;
+	default:
+		printf('<p>Geen ondersteuning voor <em>%s</em>.</p>', htmlspecialchars($type));
 	}
 	return;
 }
-- 
2.30.0