API functions for processing and sending e-mail.
<?php
/**
* @file
* API functions for processing and sending e-mail.
*/
/**
* Auto-detect appropriate line endings for e-mails.
*
* $conf['mail_line_endings'] will override this setting.
*/
define('MAIL_LINE_ENDINGS', isset($_SERVER['WINDIR']) || isset($_SERVER['SERVER_SOFTWARE']) && strpos($_SERVER['SERVER_SOFTWARE'], 'Win32') !== FALSE ? "\r\n" : "\n");
/**
* Composes and optionally sends an e-mail message.
*
* Sending an e-mail works with defining an e-mail template (subject, text
* and possibly e-mail headers) and the replacement values to use in the
* appropriate places in the template. Processed e-mail templates are
* requested from hook_mail() from the module sending the e-mail. Any module
* can modify the composed e-mail message array using hook_mail_alter().
* Finally drupal_mail_system()->mail() sends the e-mail, which can
* be reused if the exact same composed e-mail is to be sent to multiple
* recipients.
*
* Finding out what language to send the e-mail with needs some consideration.
* If you send e-mail to a user, her preferred language should be fine, so
* use user_preferred_language(). If you send email based on form values
* filled on the page, there are two additional choices if you are not
* sending the e-mail to a user on the site. You can either use the language
* used to generate the page ($language global variable) or the site default
* language. See language_default(). The former is good if sending e-mail to
* the person filling the form, the later is good if you send e-mail to an
* address previously set up (like contact addresses in a contact form).
*
* Taking care of always using the proper language is even more important
* when sending e-mails in a row to multiple users. Hook_mail() abstracts
* whether the mail text comes from an administrator setting or is
* static in the source code. It should also deal with common mail tokens,
* only receiving $params which are unique to the actual e-mail at hand.
*
* An example:
*
* @code
* function example_notify($accounts) {
* foreach ($accounts as $account) {
* $params['account'] = $account;
* // example_mail() will be called based on the first drupal_mail() parameter.
* drupal_mail('example', 'notice', $account->mail, user_preferred_language($account), $params);
* }
* }
*
* function example_mail($key, &$message, $params) {
* $data['user'] = $params['account'];
* $options['language'] = $message['language'];
* user_mail_tokens($variables, $data, $options);
* switch($key) {
* case 'notice':
* // If the recipient can receive such notices by instant-message, do
* // not send by email.
* if (example_im_send($key, $message, $params)) {
* $message['send'] = FALSE;
* break;
* }
* $langcode = $message['language']->language;
* $message['subject'] = t('Notification from !site', $variables, array('langcode' => $langcode));
* $message['body'][] = t("Dear !username\n\nThere is new content available on the site.", $variables, array('langcode' => $langcode));
* break;
* }
* }
* @endcode
*
* Another example, which uses drupal_mail() to format a message for sending
* later:
*
* @code
* $params = array('current_conditions' => $data);
* $to = 'user@example.com';
* $message = drupal_mail('example', 'notice', $to, $language, $params, FALSE);
* // Only add to the spool if sending was not canceled.
* if ($message['send']) {
* example_spool_message($message);
* }
* @endcode
*
* @param $module
* A module name to invoke hook_mail() on. The {$module}_mail() hook will be
* called to complete the $message structure which will already contain common
* defaults.
* @param $key
* A key to identify the e-mail sent. The final e-mail id for e-mail altering
* will be {$module}_{$key}.
* @param $to
* The e-mail address or addresses where the message will be sent to. The
* formatting of this string will be validated with the
* @link http://php.net/manual/filter.filters.validate.php PHP e-mail validation filter. @endlink
* Some examples are:
* - user@example.com
* - user@example.com, anotheruser@example.com
* - User <user@example.com>
* - User <user@example.com>, Another User <anotheruser@example.com>
* @param $language
* Language object to use to compose the e-mail.
* @param $params
* Optional parameters to build the e-mail.
* @param $from
* Sets From to this value, if given.
* @param $send
* If TRUE, drupal_mail() will call drupal_mail_system()->mail() to deliver
* the message, and store the result in $message['result']. Modules
* implementing hook_mail_alter() may cancel sending by setting
* $message['send'] to FALSE.
*
* @return
* The $message array structure containing all details of the
* message. If already sent ($send = TRUE), then the 'result' element
* will contain the success indicator of the e-mail, failure being already
* written to the watchdog. (Success means nothing more than the message being
* accepted at php-level, which still doesn't guarantee it to be delivered.)
*/
function drupal_mail($module, $key, $to, $language, $params = array(), $from = NULL, $send = TRUE) {
$default_from = variable_get('site_mail', ini_get('sendmail_from'));
// Bundle up the variables into a structured array for altering.
$message = array(
'id' => $module . '_' . $key,
'module' => $module,
'key' => $key,
'to' => $to,
'from' => isset($from) ? $from : $default_from,
'language' => $language,
'params' => $params,
'send' => TRUE,
'subject' => '',
'body' => array(),
);
// Build the default headers
$headers = array(
'MIME-Version' => '1.0',
'Content-Type' => 'text/plain; charset=UTF-8; format=flowed; delsp=yes',
'Content-Transfer-Encoding' => '8Bit',
'X-Mailer' => 'Drupal',
);
if ($default_from) {
// To prevent e-mail from looking like spam, the addresses in the Sender and
// Return-Path headers should have a domain authorized to use the originating
// SMTP server.
$headers['From'] = $headers['Sender'] = $headers['Return-Path'] = $default_from;
}
if ($from) {
$headers['From'] = $from;
}
$message['headers'] = $headers;
// Build the e-mail (get subject and body, allow additional headers) by
// invoking hook_mail() on this module. We cannot use module_invoke() as
// we need to have $message by reference in hook_mail().
if (function_exists($function = $module . '_mail')) {
$function($key, $message, $params);
}
// Invoke hook_mail_alter() to allow all modules to alter the resulting e-mail.
drupal_alter('mail', $message);
// Retrieve the responsible implementation for this message.
$system = drupal_mail_system($module, $key);
// Format the message body.
$message = $system
->format($message);
// Optionally send e-mail.
if ($send) {
// The original caller requested sending. Sending was canceled by one or
// more hook_mail_alter() implementations. We set 'result' to NULL, because
// FALSE indicates an error in sending.
if (empty($message['send'])) {
$message['result'] = NULL;
}
else {
$message['result'] = $system
->mail($message);
// Log errors.
if (!$message['result']) {
watchdog('mail', 'Error sending e-mail (from %from to %to).', array(
'%from' => $message['from'],
'%to' => $message['to'],
), WATCHDOG_ERROR);
drupal_set_message(t('Unable to send e-mail. Contact the site administrator if the problem persists.'), 'error');
}
}
}
return $message;
}
/**
* Returns an object that implements the MailSystemInterface interface.
*
* Allows for one or more custom mail backends to format and send mail messages
* composed using drupal_mail().
*
* An implementation needs to implement the following methods:
* - format: Allows to preprocess, format, and postprocess a mail
* message before it is passed to the sending system. By default, all messages
* may contain HTML and are converted to plain-text by the DefaultMailSystem
* implementation. For example, an alternative implementation could override
* the default implementation and additionally sanitize the HTML for usage in
* a MIME-encoded e-mail, but still invoking the DefaultMailSystem
* implementation to generate an alternate plain-text version for sending.
* - mail: Sends a message through a custom mail sending engine.
* By default, all messages are sent via PHP's mail() function by the
* DefaultMailSystem implementation.
*
* The selection of a particular implementation is controlled via the variable
* 'mail_system', which is a keyed array. The default implementation
* is the class whose name is the value of 'default-system' key. A more specific
* match first to key and then to module will be used in preference to the
* default. To specify a different class for all mail sent by one module, set
* the class name as the value for the key corresponding to the module name. To
* specify a class for a particular message sent by one module, set the class
* name as the value for the array key that is the message id, which is
* "${module}_${key}".
*
* For example to debug all mail sent by the user module by logging it to a
* file, you might set the variable as something like:
*
* @code
* array(
* 'default-system' => 'DefaultMailSystem',
* 'user' => 'DevelMailLog',
* );
* @endcode
*
* Finally, a different system can be specified for a specific e-mail ID (see
* the $key param), such as one of the keys used by the contact module:
*
* @code
* array(
* 'default-system' => 'DefaultMailSystem',
* 'user' => 'DevelMailLog',
* 'contact_page_autoreply' => 'DrupalDevNullMailSend',
* );
* @endcode
*
* Other possible uses for system include a mail-sending class that actually
* sends (or duplicates) each message to SMS, Twitter, instant message, etc, or
* a class that queues up a large number of messages for more efficient bulk
* sending or for sending via a remote gateway so as to reduce the load
* on the local server.
*
* @param $module
* The module name which was used by drupal_mail() to invoke hook_mail().
* @param $key
* A key to identify the e-mail sent. The final e-mail ID for the e-mail
* alter hook in drupal_mail() would have been {$module}_{$key}.
*
* @return MailSystemInterface
*/
function drupal_mail_system($module, $key) {
$instances =& drupal_static(__FUNCTION__, array());
$id = $module . '_' . $key;
$configuration = variable_get('mail_system', array(
'default-system' => 'DefaultMailSystem',
));
// Look for overrides for the default class, starting from the most specific
// id, and falling back to the module name.
if (isset($configuration[$id])) {
$class = $configuration[$id];
}
elseif (isset($configuration[$module])) {
$class = $configuration[$module];
}
else {
$class = $configuration['default-system'];
}
if (empty($instances[$class])) {
$interfaces = class_implements($class);
if (isset($interfaces['MailSystemInterface'])) {
$instances[$class] = new $class();
}
else {
throw new Exception(t('Class %class does not implement interface %interface', array(
'%class' => $class,
'%interface' => 'MailSystemInterface',
)));
}
}
return $instances[$class];
}
/**
* An interface for pluggable mail back-ends.
*/
interface MailSystemInterface {
/**
* Format a message composed by drupal_mail() prior sending.
*
* @param $message
* A message array, as described in hook_mail_alter().
*
* @return
* The formatted $message.
*/
public function format(array $message);
/**
* Send a message composed by drupal_mail().
*
* @param $message
* Message array with at least the following elements:
* - id: A unique identifier of the e-mail type. Examples: 'contact_user_copy',
* 'user_password_reset'.
* - to: The mail address or addresses where the message will be sent to.
* The formatting of this string will be validated with the
* @link http://php.net/manual/filter.filters.validate.php PHP e-mail validation filter. @endlink
* Some examples are:
* - user@example.com
* - user@example.com, anotheruser@example.com
* - User <user@example.com>
* - User <user@example.com>, Another User <anotheruser@example.com>
* - subject: Subject of the e-mail to be sent. This must not contain any
* newline characters, or the mail may not be sent properly.
* - body: Message to be sent. Accepts both CRLF and LF line-endings.
* E-mail bodies must be wrapped. You can use drupal_wrap_mail() for
* smart plain text wrapping.
* - headers: Associative array containing all additional mail headers not
* defined by one of the other parameters. PHP's mail() looks for Cc and
* Bcc headers and sends the mail to addresses in these headers too.
*
* @return
* TRUE if the mail was successfully accepted for delivery, otherwise FALSE.
*/
public function mail(array $message);
}
/**
* Performs format=flowed soft wrapping for mail (RFC 3676).
*
* We use delsp=yes wrapping, but only break non-spaced languages when
* absolutely necessary to avoid compatibility issues.
*
* We deliberately use LF rather than CRLF, see drupal_mail().
*
* @param string $text
* The plain text to process.
* @param string $indent (optional)
* A string to indent the text with. Only '>' characters are repeated on
* subsequent wrapped lines. Others are replaced by spaces.
*
* @return string
* The content of the email as a string with formatting applied.
*/
function drupal_wrap_mail($text, $indent = '') {
// Convert CRLF into LF.
$text = str_replace("\r", '', $text);
// See if soft-wrapping is allowed.
$clean_indent = _drupal_html_to_text_clean($indent);
$soft = strpos($clean_indent, ' ') === FALSE;
// Check if the string has line breaks.
if (strpos($text, "\n") !== FALSE) {
// Remove trailing spaces to make existing breaks hard, but leave signature
// marker untouched (RFC 3676, Section 4.3).
$text = preg_replace('/(?(?<!^--) +\\n| +\\n)/m', "\n", $text);
// Wrap each line at the needed width.
$lines = explode("\n", $text);
array_walk($lines, '_drupal_wrap_mail_line', array(
'soft' => $soft,
'length' => strlen($indent),
));
$text = implode("\n", $lines);
}
else {
// Wrap this line.
_drupal_wrap_mail_line($text, 0, array(
'soft' => $soft,
'length' => strlen($indent),
));
}
// Empty lines with nothing but spaces.
$text = preg_replace('/^ +\\n/m', "\n", $text);
// Space-stuff special lines.
$text = preg_replace('/^(>| |From)/m', ' $1', $text);
// Apply indentation. We only include non-'>' indentation on the first line.
$text = $indent . substr(preg_replace('/^/m', $clean_indent, $text), strlen($indent));
return $text;
}
/**
* Transforms an HTML string into plain text, preserving its structure.
*
* The output will be suitable for use as 'format=flowed; delsp=yes' text
* (RFC 3676) and can be passed directly to drupal_mail() for sending.
*
* We deliberately use LF rather than CRLF, see drupal_mail().
*
* This function provides suitable alternatives for the following tags:
* <a> <em> <i> <strong> <b> <br> <p> <blockquote> <ul> <ol> <li> <dl> <dt>
* <dd> <h1> <h2> <h3> <h4> <h5> <h6> <hr>
*
* @param $string
* The string to be transformed.
* @param $allowed_tags (optional)
* If supplied, a list of tags that will be transformed. If omitted, all
* all supported tags are transformed.
*
* @return
* The transformed string.
*/
function drupal_html_to_text($string, $allowed_tags = NULL) {
// Cache list of supported tags.
static $supported_tags;
if (empty($supported_tags)) {
$supported_tags = array(
'a',
'em',
'i',
'strong',
'b',
'br',
'p',
'blockquote',
'ul',
'ol',
'li',
'dl',
'dt',
'dd',
'h1',
'h2',
'h3',
'h4',
'h5',
'h6',
'hr',
);
}
// Make sure only supported tags are kept.
$allowed_tags = isset($allowed_tags) ? array_intersect($supported_tags, $allowed_tags) : $supported_tags;
// Make sure tags, entities and attributes are well-formed and properly nested.
$string = _filter_htmlcorrector(filter_xss($string, $allowed_tags));
// Apply inline styles.
$string = preg_replace('!</?(em|i)((?> +)[^>]*)?>!i', '/', $string);
$string = preg_replace('!</?(strong|b)((?> +)[^>]*)?>!i', '*', $string);
// Replace inline <a> tags with the text of link and a footnote.
// 'See <a href="http://drupal.org">the Drupal site</a>' becomes
// 'See the Drupal site [1]' with the URL included as a footnote.
_drupal_html_to_mail_urls(NULL, TRUE);
$pattern = '@(<a[^>]+?href="([^"]*)"[^>]*?>(.+?)</a>)@i';
$string = preg_replace_callback($pattern, '_drupal_html_to_mail_urls', $string);
$urls = _drupal_html_to_mail_urls();
$footnotes = '';
if (count($urls)) {
$footnotes .= "\n";
for ($i = 0, $max = count($urls); $i < $max; $i++) {
$footnotes .= '[' . ($i + 1) . '] ' . $urls[$i] . "\n";
}
}
// Split tags from text.
$split = preg_split('/<([^>]+?)>/', $string, -1, PREG_SPLIT_DELIM_CAPTURE);
// Note: PHP ensures the array consists of alternating delimiters and literals
// and begins and ends with a literal (inserting $null as required).
$tag = FALSE;
// Odd/even counter (tag or no tag)
$casing = NULL;
// Case conversion function
$output = '';
$indent = array();
// All current indentation string chunks
$lists = array();
// Array of counters for opened lists
foreach ($split as $value) {
$chunk = NULL;
// Holds a string ready to be formatted and output.
// Process HTML tags (but don't output any literally).
if ($tag) {
list($tagname) = explode(' ', strtolower($value), 2);
switch ($tagname) {
// List counters
case 'ul':
array_unshift($lists, '*');
break;
case 'ol':
array_unshift($lists, 1);
break;
case '/ul':
case '/ol':
array_shift($lists);
$chunk = '';
// Ensure blank new-line.
break;
// Quotation/list markers, non-fancy headers
case 'blockquote':
// Format=flowed indentation cannot be mixed with lists.
$indent[] = count($lists) ? ' "' : '>';
break;
case 'li':
$indent[] = isset($lists[0]) && is_numeric($lists[0]) ? ' ' . $lists[0]++ . ') ' : ' * ';
break;
case 'dd':
$indent[] = ' ';
break;
case 'h3':
$indent[] = '.... ';
break;
case 'h4':
$indent[] = '.. ';
break;
case '/blockquote':
if (count($lists)) {
// Append closing quote for inline quotes (immediately).
$output = rtrim($output, "> \n") . "\"\n";
$chunk = '';
// Ensure blank new-line.
}
// Fall-through
case '/li':
case '/dd':
array_pop($indent);
break;
case '/h3':
case '/h4':
array_pop($indent);
case '/h5':
case '/h6':
$chunk = '';
// Ensure blank new-line.
break;
// Fancy headers
case 'h1':
$indent[] = '======== ';
$casing = 'drupal_strtoupper';
break;
case 'h2':
$indent[] = '-------- ';
$casing = 'drupal_strtoupper';
break;
case '/h1':
case '/h2':
$casing = NULL;
// Pad the line with dashes.
$output = _drupal_html_to_text_pad($output, $tagname == '/h1' ? '=' : '-', ' ');
array_pop($indent);
$chunk = '';
// Ensure blank new-line.
break;
// Horizontal rulers
case 'hr':
// Insert immediately.
$output .= drupal_wrap_mail('', implode('', $indent)) . "\n";
$output = _drupal_html_to_text_pad($output, '-');
break;
// Paragraphs and definition lists
case '/p':
case '/dl':
$chunk = '';
// Ensure blank new-line.
break;
}
}
else {
// Convert inline HTML text to plain text; not removing line-breaks or
// white-space, since that breaks newlines when sanitizing plain-text.
$value = trim(decode_entities($value));
if (drupal_strlen($value)) {
$chunk = $value;
}
}
// See if there is something waiting to be output.
if (isset($chunk)) {
// Apply any necessary case conversion.
if (isset($casing)) {
$chunk = $casing($chunk);
}
// Format it and apply the current indentation.
$output .= drupal_wrap_mail($chunk, implode('', $indent)) . MAIL_LINE_ENDINGS;
// Remove non-quotation markers from indentation.
$indent = array_map('_drupal_html_to_text_clean', $indent);
}
$tag = !$tag;
}
return $output . $footnotes;
}
/**
* Wraps words on a single line.
*
* Callback for array_walk() winthin drupal_wrap_mail().
*/
function _drupal_wrap_mail_line(&$line, $key, $values) {
// Use soft-breaks only for purely quoted or unindented text.
$line = wordwrap($line, 77 - $values['length'], $values['soft'] ? " \n" : "\n");
// Break really long words at the maximum width allowed.
$line = wordwrap($line, 996 - $values['length'], $values['soft'] ? " \n" : "\n", TRUE);
}
/**
* Keeps track of URLs and replaces them with placeholder tokens.
*
* Callback for preg_replace_callback() within drupal_html_to_text().
*/
function _drupal_html_to_mail_urls($match = NULL, $reset = FALSE) {
global $base_url, $base_path;
static $urls = array(), $regexp;
if ($reset) {
// Reset internal URL list.
$urls = array();
}
else {
if (empty($regexp)) {
$regexp = '@^' . preg_quote($base_path, '@') . '@';
}
if ($match) {
list(, , $url, $label) = $match;
// Ensure all URLs are absolute.
$urls[] = strpos($url, '://') ? $url : preg_replace($regexp, $base_url . '/', $url);
return $label . ' [' . count($urls) . ']';
}
}
return $urls;
}
/**
* Replaces non-quotation markers from a given piece of indentation with spaces.
*
* Callback for array_map() within drupal_html_to_text().
*/
function _drupal_html_to_text_clean($indent) {
return preg_replace('/[^>]/', ' ', $indent);
}
/**
* Pads the last line with the given character.
*
* @see drupal_html_to_text()
*/
function _drupal_html_to_text_pad($text, $pad, $prefix = '') {
// Remove last line break.
$text = substr($text, 0, -1);
// Calculate needed padding space and add it.
if (($p = strrpos($text, "\n")) === FALSE) {
$p = -1;
}
$n = max(0, 79 - (strlen($text) - $p) - strlen($prefix));
// Add prefix and padding, and restore linebreak.
return $text . $prefix . str_repeat($pad, $n) . "\n";
}
Name | Description |
---|---|
drupal_html_to_text | Transforms an HTML string into plain text, preserving its structure. |
drupal_mail | Composes and optionally sends an e-mail message. |
drupal_mail_system | Returns an object that implements the MailSystemInterface interface. |
drupal_wrap_mail | Performs format=flowed soft wrapping for mail (RFC 3676). |
_drupal_html_to_mail_urls | Keeps track of URLs and replaces them with placeholder tokens. |
_drupal_html_to_text_clean | Replaces non-quotation markers from a given piece of indentation with spaces. |
_drupal_html_to_text_pad | Pads the last line with the given character. |
_drupal_wrap_mail_line | Wraps words on a single line. |
Name | Description |
---|---|
MAIL_LINE_ENDINGS | Auto-detect appropriate line endings for e-mails. |
Name | Description |
---|---|
MailSystemInterface | An interface for pluggable mail back-ends. |