php 52 lines · 9 steps

Parsing multipart emails with mailparse

Walk a raw MIME message into structured headers and decoded body parts using PHP's mailparse extension.

Explained by highlit
Intermediate mime-parsing email encoding resource-management
1<?php
2 
3function parseMultipartEmail(string $raw): array
4{
5 $resource = mailparse_msg_create();
6 mailparse_msg_parse($resource, $raw);
7 
8 $structure = mailparse_msg_get_structure($resource);
9 $message = [
10 'headers' => [],
11 'parts' => [],
12 ];
13 
14 $rootData = mailparse_msg_get_part_data($resource);
15 $message['headers'] = $rootData['headers'] ?? [];
16 
17 foreach ($structure as $partId) {
18 $part = mailparse_msg_get_part($resource, $partId);
19 $data = mailparse_msg_get_part_data($part);
20 
21 $contentType = $data['content-type'] ?? 'text/plain';
22 if (str_starts_with($contentType, 'multipart/')) {
23 continue;
24 }
25 
26 $body = mailparse_msg_extract_part_file(
27 $part,
28 $raw,
29 null
30 );
31 
32 $encoding = strtolower($data['transfer-encoding'] ?? '');
33 $body = match ($encoding) {
34 'base64' => base64_decode($body),
35 'quoted-printable' => quoted_printable_decode($body),
36 default => $body,
37 };
38 
39 $message['parts'][] = [
40 'id' => $partId,
41 'content_type' => $contentType,
42 'charset' => $data['charset'] ?? 'us-ascii',
43 'disposition' => $data['content-disposition'] ?? 'inline',
44 'filename' => $data['disposition-filename'] ?? $data['content-name'] ?? null,
45 'body' => $body,
46 ];
47 }
48 
49 mailparse_msg_free($resource);
50 
51 return $message;
52}
01 / 01
STEP 01

Walkthrough

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Three takeaways
  1. 1MIME messages are a tree, so skipping multipart container nodes leaves you with only the real leaf content.
  2. 2Transfer encodings like base64 and quoted-printable must be decoded before a body is usable.
  3. 3Extension resources need explicit cleanup — free them once you've extracted everything you need.

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