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PhabricatorMailEmailEngine.php
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			<?php

			final class PhabricatorMailEmailEngine
			extends PhabricatorMailMessageEngine {

			public function newMessage() {
			$mailer = $this->getMailer();
			$mail = $this->getMail();

			$message = new PhabricatorMailEmailMessage();

			$from_address = $this->newFromEmailAddress();
			$message->setFromAddress($from_address);

			$reply_address = $this->newReplyToEmailAddress();
			if ($reply_address) {
			$message->setReplyToAddress($reply_address);
			}

			$to_addresses = $this->newToEmailAddresses();
			$cc_addresses = $this->newCCEmailAddresses();

			if (!$to_addresses && !$cc_addresses) {
			$mail->setMessage(
			pht(
			'Message has no valid recipients: all To/CC are disabled, '.
			'invalid, or configured not to receive this mail.'));
			return null;
			}

			// If this email describes a mail processing error, we rate limit outbound
			// messages to each individual address. This prevents messes where
			// something is stuck in a loop or dumps a ton of messages on us suddenly.
			if ($mail->getIsErrorEmail()) {
			$all_recipients = array();
			foreach ($to_addresses as $to_address) {
			$all_recipients[] = $to_address->getAddress();
			}
			foreach ($cc_addresses as $cc_address) {
			$all_recipients[] = $cc_address->getAddress();
			}
			if ($this->shouldRateLimitMail($all_recipients)) {
			$mail->setMessage(
			pht(
			'This is an error email, but one or more recipients have '.
			'exceeded the error email rate limit. Declining to deliver '.
			'message.'));
			return null;
			}
			}

			// Some mailers require a valid "To:" in order to deliver mail. If we
			// don't have any "To:", try to fill it in with a placeholder "To:".
			// If that also fails, move the "Cc:" line to "To:".
			if (!$to_addresses) {
			$void_address = $this->newVoidEmailAddress();
			$to_addresses = array($void_address);
			}

			$to_addresses = $this->getUniqueEmailAddresses($to_addresses);
			$cc_addresses = $this->getUniqueEmailAddresses(
			$cc_addresses,
			$to_addresses);

			$message->setToAddresses($to_addresses);
			$message->setCCAddresses($cc_addresses);

			$attachments = $this->newEmailAttachments();
			$message->setAttachments($attachments);

			$subject = $this->newEmailSubject();
			$message->setSubject($subject);

			$headers = $this->newEmailHeaders();
			foreach ($this->newEmailThreadingHeaders() as $threading_header) {
			$headers[] = $threading_header;
			}

			$stamps = $mail->getMailStamps();
			if ($stamps) {
			$headers[] = $this->newEmailHeader(
			'X-Phabricator-Stamps',
			implode(' ', $stamps));
			}

			$must_encrypt = $mail->getMustEncrypt();

			$raw_body = $mail->getBody();
			$body = $raw_body;
			if ($must_encrypt) {
			$parts = array();

			$encrypt_uri = $mail->getMustEncryptURI();
			if (!strlen($encrypt_uri)) {
			$encrypt_phid = $mail->getRelatedPHID();
			if ($encrypt_phid) {
			$encrypt_uri = urisprintf(
			'/object/%s/',
			$encrypt_phid);
			}
			}

			if (strlen($encrypt_uri)) {
			$parts[] = pht(
			'This secure message is notifying you of a change to this object:');
			$parts[] = PhabricatorEnv::getProductionURI($encrypt_uri);
			}

			$parts[] = pht(
			'The content for this message can only be transmitted over a '.
			'secure channel. To view the message content, follow this '.
			'link:');

			$parts[] = PhabricatorEnv::getProductionURI($mail->getURI());

			$body = implode("\n\n", $parts);
			} else {
			$body = $raw_body;
			}

			$body_limit = PhabricatorEnv::getEnvConfig('metamta.email-body-limit');

			$body = phutil_string_cast($body);
			if (strlen($body) > $body_limit) {
			$body = id(new PhutilUTF8StringTruncator())
			->setMaximumBytes($body_limit)
			->truncateString($body);
			$body .= "\n";
			$body .= pht('(This email was truncated at %d bytes.)', $body_limit);
			}
			$message->setTextBody($body);
			$body_limit -= strlen($body);

			// If we sent a different message body than we were asked to, record
			// what we actually sent to make debugging and diagnostics easier.
			if ($body !== $raw_body) {
			$mail->setDeliveredBody($body);
			}

			if ($must_encrypt) {
			$send_html = false;
			} else {
			$send_html = $this->shouldSendHTML();
			}

			if ($send_html) {
			$html_body = $mail->getHTMLBody();
			if (phutil_nonempty_string($html_body)) {
			// NOTE: We just drop the entire HTML body if it won't fit. Safely
			// truncating HTML is hard, and we already have the text body to fall
			// back to.
			if (strlen($html_body) <= $body_limit) {
			$message->setHTMLBody($html_body);
			$body_limit -= strlen($html_body);
			}
			}
			}

			// Pass the headers to the mailer, then save the state so we can show
			// them in the web UI. If the mail must be encrypted, we remove headers
			// which are not on a strict whitelist to avoid disclosing information.
			$filtered_headers = $this->filterHeaders($headers, $must_encrypt);
			$message->setHeaders($filtered_headers);

			$mail->setUnfilteredHeaders($headers);
			$mail->setDeliveredHeaders($headers);

			if (PhabricatorEnv::getEnvConfig('phabricator.silent')) {
			$mail->setMessage(
			pht(
			'This software is running in silent mode. See `%s` '.
			'in the configuration to change this setting.',
			'phabricator.silent'));

			return null;
			}

			return $message;
			}

			/* -( Message Components )------------------------------------------------- */

			private function newFromEmailAddress() {
			$from_address = $this->newDefaultEmailAddress();
			$mail = $this->getMail();

			// If the mail content must be encrypted, always disguise the sender.
			$must_encrypt = $mail->getMustEncrypt();
			if ($must_encrypt) {
			return $from_address;
			}

			// If we have a raw "From" address, use that.
			$raw_from = $mail->getRawFrom();
			if ($raw_from) {
			list($from_email, $from_name) = $raw_from;
			return $this->newEmailAddress($from_email, $from_name);
			}

			// Otherwise, use as much of the information for any sending entity as
			// we can.
			$from_phid = $mail->getFrom();

			$actor = $this->getActor($from_phid);
			if ($actor) {
			$actor_email = $actor->getEmailAddress();
			$actor_name = $actor->getName();
			} else {
			$actor_email = null;
			$actor_name = null;
			}

			$send_as_user = PhabricatorEnv::getEnvConfig('metamta.can-send-as-user');
			if ($send_as_user) {
			if ($actor_email !== null) {
			$from_address->setAddress($actor_email);
			}
			}

			if ($actor_name !== null) {
			$from_address->setDisplayName($actor_name);
			}

			return $from_address;
			}

			private function newReplyToEmailAddress() {
			$mail = $this->getMail();

			$reply_raw = $mail->getReplyTo();
			if (!phutil_nonempty_string($reply_raw)) {
			return null;
			}

			$reply_address = new PhutilEmailAddress($reply_raw);

			// If we have a sending object, change the display name.
			$from_phid = $mail->getFrom();
			$actor = $this->getActor($from_phid);
			if ($actor) {
			$reply_address->setDisplayName($actor->getName());
			}

			// If we don't have a display name, fill in a default.
			if (!strlen($reply_address->getDisplayName())) {
			$reply_address->setDisplayName(PlatformSymbols::getPlatformServerName());
			}

			return $reply_address;
			}

			private function newToEmailAddresses() {
			$mail = $this->getMail();

			$phids = $mail->getToPHIDs();
			$addresses = $this->newEmailAddressesFromActorPHIDs($phids);

			foreach ($mail->getRawToAddresses() as $raw_address) {
			$addresses[] = new PhutilEmailAddress($raw_address);
			}

			return $addresses;
			}

			private function newCCEmailAddresses() {
			$mail = $this->getMail();
			$phids = $mail->getCcPHIDs();
			return $this->newEmailAddressesFromActorPHIDs($phids);
			}

			private function newEmailAddressesFromActorPHIDs(array $phids) {
			$mail = $this->getMail();
			$phids = $mail->expandRecipients($phids);

			$addresses = array();
			foreach ($phids as $phid) {
			$actor = $this->getActor($phid);
			if (!$actor) {
			continue;
			}

			if (!$actor->isDeliverable()) {
			continue;
			}

			$addresses[] = new PhutilEmailAddress($actor->getEmailAddress());
			}

			return $addresses;
			}

			private function newEmailSubject() {
			$mail = $this->getMail();

			$is_threaded = (bool)$mail->getThreadID();
			$must_encrypt = $mail->getMustEncrypt();

			$subject = array();

			if ($is_threaded) {
			if ($this->shouldAddRePrefix()) {
			$subject[] = 'Re:';
			}
			}

			$subject_prefix = $mail->getSubjectPrefix();
			$subject_prefix = phutil_string_cast($subject_prefix);
			$subject_prefix = trim($subject_prefix);

			$subject[] = $subject_prefix;

			// If mail content must be encrypted, we replace the subject with
			// a generic one.
			if ($must_encrypt) {
			$encrypt_subject = $mail->getMustEncryptSubject();
			if (!strlen($encrypt_subject)) {
			$encrypt_subject = pht('Object Updated');
			}
			$subject[] = $encrypt_subject;
			} else {
			$vary_prefix = $mail->getVarySubjectPrefix();
			if (phutil_nonempty_string($vary_prefix)) {
			if ($this->shouldVarySubject()) {
			$subject[] = $vary_prefix;
			}
			}

			$subject[] = $mail->getSubject();
			}

			foreach ($subject as $key => $part) {
			if (!phutil_nonempty_string($part)) {
			unset($subject[$key]);
			}
			}

			$subject = implode(' ', $subject);
			return $subject;
			}

			private function newEmailHeaders() {
			$mail = $this->getMail();

			$headers = array();

			$headers[] = $this->newEmailHeader(
			'X-Phabricator-Sent-This-Message',
			'Yes');
			$headers[] = $this->newEmailHeader(
			'X-Mail-Transport-Agent',
			'MetaMTA');

			// Some clients respect this to suppress OOF and other auto-responses.
			$headers[] = $this->newEmailHeader(
			'X-Auto-Response-Suppress',
			'All');

			$mailtags = $mail->getMailTags();
			if ($mailtags) {
			$tag_header = array();
			foreach ($mailtags as $mailtag) {
			$tag_header[] = '<'.$mailtag.'>';
			}
			$tag_header = implode(', ', $tag_header);
			$headers[] = $this->newEmailHeader(
			'X-Phabricator-Mail-Tags',
			$tag_header);
			}

			$value = $mail->getHeaders();
			foreach ($value as $pair) {
			list($header_key, $header_value) = $pair;

			// NOTE: If we have \n in a header, SES rejects the email.
			$header_value = str_replace("\n", ' ', $header_value);
			$headers[] = $this->newEmailHeader($header_key, $header_value);
			}

			$is_bulk = $mail->getIsBulk();
			if ($is_bulk) {
			$headers[] = $this->newEmailHeader('Precedence', 'bulk');
			}

			if ($mail->getMustEncrypt()) {
			$headers[] = $this->newEmailHeader('X-Phabricator-Must-Encrypt', 'Yes');
			}

			$related_phid = $mail->getRelatedPHID();
			if ($related_phid) {
			$headers[] = $this->newEmailHeader('Thread-Topic', $related_phid);
			}

			$headers[] = $this->newEmailHeader(
			'X-Phabricator-Mail-ID',
			$mail->getID());

			$unique = Filesystem::readRandomCharacters(16);
			$headers[] = $this->newEmailHeader(
			'X-Phabricator-Send-Attempt',
			$unique);

			return $headers;
			}

			private function newEmailThreadingHeaders() {
			$mailer = $this->getMailer();
			$mail = $this->getMail();

			$headers = array();

			$thread_id = $mail->getThreadID();
			if (!phutil_nonempty_string($thread_id)) {
			return $headers;
			}

			$is_first = $mail->getIsFirstMessage();

			// NOTE: Gmail freaks out about In-Reply-To and References which aren't in
			// the form "<string@domain.tld>"; this is also required by RFC 2822,
			// although some clients are more liberal in what they accept.
			$domain = $this->newMailDomain();
			$thread_id = '<'.$thread_id.'@'.$domain.'>';

			if ($is_first && $mailer->supportsMessageIDHeader()) {
			$headers[] = $this->newEmailHeader('Message-ID', $thread_id);
			} else {
			$in_reply_to = $thread_id;
			$references = array($thread_id);
			$parent_id = $mail->getParentMessageID();
			if ($parent_id) {
			$in_reply_to = $parent_id;
			// By RFC 2822, the most immediate parent should appear last
			// in the "References" header, so this order is intentional.
			$references[] = $parent_id;
			}
			$references = implode(' ', $references);
			$headers[] = $this->newEmailHeader('In-Reply-To', $in_reply_to);
			$headers[] = $this->newEmailHeader('References', $references);
			}
			$thread_index = $this->generateThreadIndex($thread_id, $is_first);
			$headers[] = $this->newEmailHeader('Thread-Index', $thread_index);

			return $headers;
			}

			private function newEmailAttachments() {
			$mail = $this->getMail();

			// If the mail content must be encrypted, don't add attachments.
			$must_encrypt = $mail->getMustEncrypt();
			if ($must_encrypt) {
			return array();
			}

			return $mail->getAttachments();
			}

			/* -( Preferences )-------------------------------------------------------- */

			private function shouldAddRePrefix() {
			$preferences = $this->getPreferences();

			$value = $preferences->getSettingValue(
			PhabricatorEmailRePrefixSetting::SETTINGKEY);

			return ($value == PhabricatorEmailRePrefixSetting::VALUE_RE_PREFIX);
			}

			private function shouldVarySubject() {
			$preferences = $this->getPreferences();

			$value = $preferences->getSettingValue(
			PhabricatorEmailVarySubjectsSetting::SETTINGKEY);

			return ($value == PhabricatorEmailVarySubjectsSetting::VALUE_VARY_SUBJECTS);
			}

			private function shouldSendHTML() {
			$preferences = $this->getPreferences();

			$value = $preferences->getSettingValue(
			PhabricatorEmailFormatSetting::SETTINGKEY);

			return ($value == PhabricatorEmailFormatSetting::VALUE_HTML_EMAIL);
			}


			/* -( Utilities )---------------------------------------------------------- */

			private function newEmailHeader($name, $value) {
			return id(new PhabricatorMailHeader())
			->setName($name)
			->setValue($value);
			}

			private function newEmailAddress($address, $name = null) {
			$object = id(new PhutilEmailAddress())
			->setAddress($address);

			if (strlen($name)) {
			$object->setDisplayName($name);
			}

			return $object;
			}

			public function newDefaultEmailAddress() {
			$raw_address = PhabricatorEnv::getEnvConfig('metamta.default-address');

			if (!$raw_address) {
			$domain = $this->newMailDomain();
			$raw_address = "noreply@{$domain}";
			}

			$address = new PhutilEmailAddress($raw_address);

			if (!phutil_nonempty_string($address->getDisplayName())) {
			$address->setDisplayName(PlatformSymbols::getPlatformServerName());
			}

			return $address;
			}

			public function newVoidEmailAddress() {
			return $this->newDefaultEmailAddress();
			}

			private function newMailDomain() {
			$domain = PhabricatorEnv::getEnvConfig('metamta.reply-handler-domain');
			if ($domain) {
			return $domain;
			}

			$install_uri = PhabricatorEnv::getURI('/');
			$install_uri = new PhutilURI($install_uri);

			return $install_uri->getDomain();
			}

			private function filterHeaders(array $headers, $must_encrypt) {
			assert_instances_of($headers, 'PhabricatorMailHeader');

			if (!$must_encrypt) {
			return $headers;
			}

			$whitelist = array(
			'In-Reply-To',
			'Message-ID',
			'Precedence',
			'References',
			'Thread-Index',
			'Thread-Topic',

			'X-Mail-Transport-Agent',
			'X-Auto-Response-Suppress',

			'X-Phabricator-Sent-This-Message',
			'X-Phabricator-Must-Encrypt',
			'X-Phabricator-Mail-ID',
			'X-Phabricator-Send-Attempt',
			);

			// NOTE: The major header we want to drop is "X-Phabricator-Mail-Tags".
			// This header contains a significant amount of meaningful information
			// about the object.

			$whitelist_map = array();
			foreach ($whitelist as $term) {
			$whitelist_map[phutil_utf8_strtolower($term)] = true;
			}

			foreach ($headers as $key => $header) {
			$name = $header->getName();
			$name = phutil_utf8_strtolower($name);

			if (!isset($whitelist_map[$name])) {
			unset($headers[$key]);
			}
			}

			return $headers;
			}

			private function getUniqueEmailAddresses(
			array $addresses,
			array $exclude = array()) {
			assert_instances_of($addresses, 'PhutilEmailAddress');
			assert_instances_of($exclude, 'PhutilEmailAddress');

			$seen = array();

			foreach ($exclude as $address) {
			$seen[$address->getAddress()] = true;
			}

			foreach ($addresses as $key => $address) {
			$raw_address = $address->getAddress();

			if (isset($seen[$raw_address])) {
			unset($addresses[$key]);
			continue;
			}

			$seen[$raw_address] = true;
			}

			return array_values($addresses);
			}

			private function generateThreadIndex($seed, $is_first_mail) {
			// When threading, Outlook ignores the 'References' and 'In-Reply-To'
			// headers that most clients use. Instead, it uses a custom 'Thread-Index'
			// header. The format of this header is something like this (from
			// camel-exchange-folder.c in Evolution Exchange):

			/* A new post to a folder gets a 27-byte-long thread index. (The value
			* is apparently unique but meaningless.) Each reply to a post gets a
			* 32-byte-long thread index whose first 27 bytes are the same as the
			* parent's thread index. Each reply to any of those gets a
			* 37-byte-long thread index, etc. The Thread-Index header contains a
			* base64 representation of this value.
			*/

			// The specific implementation uses a 27-byte header for the first email
			// a recipient receives, and a random 5-byte suffix (32 bytes total)
			// thereafter. This means that all the replies are (incorrectly) siblings,
			// but it would be very difficult to keep track of the entire tree and this
			// gets us reasonable client behavior.

			$base = substr(md5($seed), 0, 27);
			if (!$is_first_mail) {
			// Not totally sure, but it seems like outlook orders replies by
			// thread-index rather than timestamp, so to get these to show up in the
			// right order we use the time as the last 4 bytes.
			$base .= ' '.pack('N', time());
			}

			return base64_encode($base);
			}

			private function shouldRateLimitMail(array $all_recipients) {
			try {
			PhabricatorSystemActionEngine::willTakeAction(
			$all_recipients,
			new PhabricatorMetaMTAErrorMailAction(),
			1);
			return false;
			} catch (PhabricatorSystemActionRateLimitException $ex) {
			return true;
			}
			}

			}

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phorge/src/applications/metamta/engine/PhabricatorMailEmailEngine.phpe81eff68e581HEAD -> master

PhabricatorMailEmailEngine.phpView Options

Owner Packages

phorge/src/applications/metamta/engine/PhabricatorMailEmailEngine.php
e81eff68e581HEAD -> master

PhabricatorMailEmailEngine.php
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