feat: add mime builder for smtp and imap

Signed-off-by: Sebastian Krupinski <krupinski01@gmail.com>
This commit is contained in:
2026-06-23 16:27:37 -04:00
parent d94b1ea211
commit e031831719
3 changed files with 763 additions and 6 deletions
+271
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<?php
declare(strict_types=1);
/**
* SPDX-FileCopyrightText: Sebastian Krupinski <krupinski01@gmail.com>
* SPDX-License-Identifier: AGPL-3.0-or-later
*/
namespace KTXM\ProviderImap\Mime;
use DateTimeImmutable;
use KTXF\Mail\Object\AddressInterface;
use KTXF\Mail\Object\MessagePartInterface;
use KTXF\Mail\Object\MessagePropertiesBaseInterface;
use Symfony\Component\Mime\Address as MimeAddress;
use Symfony\Component\Mime\Email;
use Symfony\Component\Mime\Part\DataPart;
/**
* MIME Message Builder
*
* Converts a framework {@see MessagePropertiesBaseInterface} into raw RFC822
* bytes. The output is transport-neutral and used by both of this module's
* outbound paths: the SMTP DATA payload (submission) and the IMAP APPEND
* literal (saving a copy to the Sent collection).
*
* The MIME engine (symfony/mime) is intentionally hidden behind this API so it
* can be swapped without touching consumers.
*
* @since 2026.06.22
*/
final class MessageBuilder
{
/**
* Headers that are derived from structured properties and therefore must
* not be copied verbatim from {@see MessagePropertiesBaseInterface::getHeaders()}.
*
* @var list<string>
*/
private const RESERVED_HEADERS = [
'from', 'sender', 'reply-to', 'to', 'cc', 'bcc', 'subject', 'date',
'message-id', 'mime-version', 'content-type', 'content-transfer-encoding',
'in-reply-to', 'references', 'bcc',
];
/**
* Build the complete RFC822 message bytes for the given properties.
*/
public function build(MessagePropertiesBaseInterface $message): string
{
return $this->toEmail($message)->toString();
}
/**
* Collect the envelope recipients (To + Cc + Bcc) as bare e-mail addresses.
*
* Useful for the SMTP RCPT TO phase, which needs every recipient including
* Bcc, even though Bcc never appears in the rendered headers.
*
* @return list<string>
*/
public static function recipients(MessagePropertiesBaseInterface $message): array
{
$recipients = [];
foreach ([...$message->getTo(), ...$message->getCc(), ...$message->getBcc()] as $address) {
$email = trim($address->getAddress());
if ($email !== '' && !in_array($email, $recipients, true)) {
$recipients[] = $email;
}
}
return $recipients;
}
private function toEmail(MessagePropertiesBaseInterface $message): Email
{
$email = new Email();
if (($from = $message->getFrom()) !== null) {
$email->from($this->address($from));
}
if (($sender = $message->getSender()) !== null) {
$email->sender($this->address($sender));
}
$replyTo = $this->addresses($message->getReplyTo());
if ($replyTo !== []) {
$email->replyTo(...$replyTo);
}
$to = $this->addresses($message->getTo());
if ($to !== []) {
$email->to(...$to);
}
$cc = $this->addresses($message->getCc());
if ($cc !== []) {
$email->cc(...$cc);
}
$bcc = $this->addresses($message->getBcc());
if ($bcc !== []) {
$email->bcc(...$bcc);
}
$email->subject($message->getSubject());
if (($sent = $message->getSent()) !== null) {
$email->date($sent instanceof DateTimeImmutable ? $sent : DateTimeImmutable::createFromInterface($sent));
}
$text = $message->getBodyTextPlain();
$html = $message->getBodyTextHtml();
// Inline attachments may carry Content-IDs without an "@"; those must be
// normalised (symfony requires an "@") and the matching cid: references
// in the HTML body rewritten so the parts still resolve.
$cidRewrites = $this->inlineCidRewrites($message);
if ($text !== null && $text !== '') {
$email->text($text);
}
if ($html !== null && $html !== '') {
$email->html($this->rewriteCids($html, $cidRewrites));
}
// Guarantee at least an (empty) text part so the message is well-formed.
if (($text === null || $text === '') && ($html === null || $html === '')) {
$email->text('');
}
foreach ($message->getAttachments() as $attachment) {
$part = $this->attachmentPart($attachment);
if ($part !== null) {
$email->addPart($part);
}
}
$this->applyThreadHeaders($email, $message);
$this->applyCustomHeaders($email, $message);
return $email;
}
private function attachmentPart(MessagePartInterface $attachment): ?DataPart
{
$content = $attachment->getContent();
if ($content === null) {
return null;
}
$part = new DataPart(
$content,
$attachment->getName(),
$attachment->getType() ?? 'application/octet-stream',
);
if ($attachment->getDisposition() === 'inline') {
$part->asInline();
$cid = $attachment->getContentId();
if ($cid !== null && $cid !== '') {
$part->setContentId($this->normalizeContentId(trim($cid, '<>')));
}
}
return $part;
}
/**
* Build a map of original => normalised Content-IDs for inline parts whose
* id required normalisation (i.e. lacked an "@").
*
* @return array<string,string>
*/
private function inlineCidRewrites(MessagePropertiesBaseInterface $message): array
{
$rewrites = [];
foreach ($message->getAttachments() as $attachment) {
if ($attachment->getDisposition() !== 'inline') {
continue;
}
$cid = $attachment->getContentId();
if ($cid === null || $cid === '') {
continue;
}
$original = trim($cid, '<>');
$normalized = $this->normalizeContentId($original);
if ($original !== $normalized) {
$rewrites[$original] = $normalized;
}
}
return $rewrites;
}
/**
* @param array<string,string> $rewrites
*/
private function rewriteCids(string $html, array $rewrites): string
{
foreach ($rewrites as $original => $normalized) {
$html = str_replace('cid:' . $original, 'cid:' . $normalized, $html);
}
return $html;
}
private function normalizeContentId(string $cid): string
{
return str_contains($cid, '@') ? $cid : $cid . '@ktrix';
}
private function applyThreadHeaders(Email $email, MessagePropertiesBaseInterface $message): void
{
$headers = $email->getHeaders();
$inReplyTo = $message->getInReplyTo();
if ($inReplyTo !== null && $inReplyTo !== '') {
$headers->addIdHeader('In-Reply-To', $this->stripBrackets($inReplyTo));
}
$references = array_values(array_filter(array_map(
fn (string $id): string => $this->stripBrackets($id),
$message->getReferences(),
), static fn (string $id): bool => $id !== ''));
if ($references !== []) {
$headers->addIdHeader('References', $references);
}
}
private function applyCustomHeaders(Email $email, MessagePropertiesBaseInterface $message): void
{
$headers = $email->getHeaders();
foreach ($message->getHeaders() as $name => $value) {
if (!is_string($name) || $value === null) {
continue;
}
if (in_array(strtolower($name), self::RESERVED_HEADERS, true)) {
continue;
}
$headers->addTextHeader($name, is_array($value) ? implode(', ', $value) : (string) $value);
}
}
/**
* @param array<int,AddressInterface> $addresses
* @return list<MimeAddress>
*/
private function addresses(array $addresses): array
{
$result = [];
foreach ($addresses as $address) {
if ($address instanceof AddressInterface && trim($address->getAddress()) !== '') {
$result[] = $this->address($address);
}
}
return $result;
}
private function address(AddressInterface $address): MimeAddress
{
return new MimeAddress($address->getAddress(), $address->getLabel() ?? '');
}
private function stripBrackets(string $id): string
{
return trim($id, " \t<>");
}
}