<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<refentry xml:id="function.mail" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
 <refnamediv>
  <refname>mail</refname>
  <refpurpose>Send mail</refpurpose>
 </refnamediv>

 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>bool</type><methodname>mail</methodname>
   <methodparam><type>string</type><parameter>to</parameter></methodparam>
   <methodparam><type>string</type><parameter>subject</parameter></methodparam>
   <methodparam><type>string</type><parameter>message</parameter></methodparam>
   <methodparam choice="opt"><type class="union"><type>array</type><type>string</type></type><parameter>additional_headers</parameter><initializer>[]</initializer></methodparam>
   <methodparam choice="opt"><type>string</type><parameter>additional_params</parameter><initializer>""</initializer></methodparam>
  </methodsynopsis>
  <para>
   Sends an email.
  </para>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>to</parameter></term>
     <listitem>
      <para>
       Receiver, or receivers of the mail.
      </para>
      <para>
       The formatting of this string must comply with
       <link xlink:href="&url.rfc;2822">RFC 2822</link>. Some examples are:
       <simplelist>
        <member>user@example.com</member>
        <member>user@example.com, anotheruser@example.com</member>
        <member>User &lt;user@example.com&gt;</member>
        <member>User &lt;user@example.com&gt;, Another User &lt;anotheruser@example.com&gt;</member>
       </simplelist>
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>subject</parameter></term>
     <listitem>
      <para>
       Subject of the email to be sent.
      </para>
      <caution>
       <para>
        Subject must satisfy <link xlink:href="&url.rfc;2047">RFC 2047</link>.
       </para>
      </caution>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>message</parameter></term>
     <listitem>
      <para>
       Message to be sent.
      </para>
      <para>
       Each line should be separated with a CRLF (\r\n). Lines should not be
       larger than 70 characters.
      </para>
      <caution>
       <para>
        (Windows only) When PHP is talking to a SMTP server directly, if a full
        stop is found on the start of a line, it is removed. To counter-act this,
        replace these occurrences with a double dot.
        <programlisting role="php">
<![CDATA[
<?php
$text = str_replace("\n.", "\n..", $text);
?>
]]>
        </programlisting>
       </para>
      </caution>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>additional_headers</parameter> (optional)</term>
     <listitem>
      <para>
       <type>String</type> or <type>array</type> to be inserted at the end of the email header.
      </para>
      <para>
       This is typically used to add extra headers (From, Cc, and Bcc).
       Multiple extra headers should be separated with a CRLF (\r\n).
       If outside data are used to compose this header, the data should be sanitized
       so that no unwanted headers could be injected. 
      </para>
      <para>
       If an <type>array</type> is passed, its keys are the header names and its
       values are the respective header values.
      </para>
      <note>
       <para>
        Before PHP 5.4.42 and 5.5.27, repectively, <parameter>additional_headers</parameter> did not have mail header
        injection protection. Therefore, users must make sure specified headers
        are safe and contains headers only. i.e. Never start mail body by putting
        multiple newlines.
       </para>
      </note>      
      <note>
       <para>
        When sending mail, the mail <emphasis>must</emphasis> contain
        a <literal>From</literal> header. This can be set with the
        <parameter>additional_headers</parameter> parameter, or a default
        can be set in &php.ini;.
       </para>
       <para>
        Failing to do this will result in an error
        message similar to <literal>Warning: mail(): "sendmail_from" not
        set in php.ini or custom "From:" header missing</literal>.
        The <literal>From</literal> header sets also
        <literal>Return-Path</literal> when sending directly via SMTP (Windows only).
       </para>
      </note>
      <note>
       <para>
        If messages are not received, try using a LF (\n) only.
        Some Unix mail transfer agents (most notably
        <link xlink:href="&url.qmail;">qmail</link>) replace LF by CRLF
        automatically (which leads to doubling CR if CRLF is used).
        This should be a last resort, as it does not comply with
        <link xlink:href="&url.rfc;2822">RFC 2822</link>.
       </para>
      </note>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>additional_params</parameter> (optional)</term>
     <listitem>
      <para>
       The <parameter>additional_params</parameter> parameter
       can be used to pass additional flags as command line options to the
       program configured to be used when sending mail, as defined by the
       <literal>sendmail_path</literal> configuration setting. For example,
       this can be used to set the envelope sender address when using
       sendmail with the <literal>-f</literal> sendmail option.
      </para>
      <para>
       This parameter is escaped by <function>escapeshellcmd</function> internally
       to prevent command execution. <function>escapeshellcmd</function> prevents
       command execution, but allows to add additional parameters. For security reasons,
       it is recommended for the user to sanitize this parameter to avoid adding unwanted
       parameters to the shell command.
      </para>
      <para>
       Since <function>escapeshellcmd</function> is applied automatically, some characters
       that are allowed as email addresses by internet RFCs cannot be used. 
       <function>mail</function> can not allow such characters, so in programs where the use of
       such characters is required, alternative means of sending emails (such as using a framework
       or a library) is recommended. 
      </para>
      <para>
       The user that the webserver runs as should be added as a trusted user to the
       sendmail configuration to prevent a 'X-Warning' header from being added
       to the message when the envelope sender (-f) is set using this method.
       For sendmail users, this file is <filename>/etc/mail/trusted-users</filename>.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns &true; if the mail was successfully accepted for delivery, &false; otherwise.
  </para>
  <para>
   It is important to note that just because the mail was accepted for delivery,
   it does NOT mean the mail will actually reach the intended destination.
  </para>
 </refsect1>

 <refsect1 role="changelog">
  &reftitle.changelog;
  <para>
   <informaltable>
    <tgroup cols="2">
     <thead>
      <row>
       <entry>&Version;</entry>
       <entry>&Description;</entry>
      </row>
     </thead>
     <tbody>
      <row>
       <entry>7.2.0</entry>
       <entry>
        The <parameter>additional_headers</parameter> parameter now also accepts
        an <type>array</type>.
       </entry>
      </row>
     </tbody>
    </tgroup>
   </informaltable>
  </para>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title>Sending mail.</title>
    <para>
     Using <function>mail</function> to send a simple email:
    </para>
    <programlisting role="php">
<![CDATA[
<?php
// The message
$message = "Line 1\r\nLine 2\r\nLine 3";

// In case any of our lines are larger than 70 characters, we should use wordwrap()
$message = wordwrap($message, 70, "\r\n");

// Send
mail('caffeinated@example.com', 'My Subject', $message);
?>
]]>
    </programlisting>
   </example>
   <example>
    <title>Sending mail with extra headers.</title>
    <para>
     The addition of basic headers, telling the MUA
     the From and Reply-To addresses:
    </para>
    <programlisting role="php">
<![CDATA[
<?php
$to      = 'nobody@example.com';
$subject = 'the subject';
$message = 'hello';
$headers = 'From: webmaster@example.com' . "\r\n" .
    'Reply-To: webmaster@example.com' . "\r\n" .
    'X-Mailer: PHP/' . phpversion();

mail($to, $subject, $message, $headers);
?>
]]>
    </programlisting>
   </example>
   <example>
    <title>Sending mail with extra headers as <type>array</type></title>
    <para>
     This example sends the same mail as the example immediately above, but
     passes the additional headers as array (available as of PHP 7.2.0).
    </para>
    <programlisting role="php">
<![CDATA[
<?php
$to      = 'nobody@example.com';
$subject = 'the subject';
$message = 'hello';
$headers = array(
    'From' => 'webmaster@example.com',
    'Reply-To' => 'webmaster@example.com',
    'X-Mailer' => 'PHP/' . phpversion()
);

mail($to, $subject, $message, $headers);
?>
]]>
    </programlisting>
   </example>
   <example>
    <title>Sending mail with an additional command line parameter.</title>
    <para>
     The <parameter>additional_params</parameter> parameter
     can be used to pass an additional parameter to the program configured
     to use when sending mail using the <literal>sendmail_path</literal>.
    </para>
    <programlisting role="php">
<![CDATA[
<?php
mail('nobody@example.com', 'the subject', 'the message', null,
   '-fwebmaster@example.com');
?>
]]>
    </programlisting>
   </example>
   <example>
    <title>Sending HTML email</title>
    <para>
     It is also possible to send HTML email with <function>mail</function>.
    </para>
    <programlisting role="php">
<![CDATA[
<?php
// Multiple recipients
$to = 'johny@example.com, sally@example.com'; // note the comma

// Subject
$subject = 'Birthday Reminders for August';

// Message
$message = '
<html>
<head>
  <title>Birthday Reminders for August</title>
</head>
<body>
  <p>Here are the birthdays upcoming in August!</p>
  <table>
    <tr>
      <th>Person</th><th>Day</th><th>Month</th><th>Year</th>
    </tr>
    <tr>
      <td>Johny</td><td>10th</td><td>August</td><td>1970</td>
    </tr>
    <tr>
      <td>Sally</td><td>17th</td><td>August</td><td>1973</td>
    </tr>
  </table>
</body>
</html>
';

// To send HTML mail, the Content-type header must be set
$headers[] = 'MIME-Version: 1.0';
$headers[] = 'Content-type: text/html; charset=iso-8859-1';

// Additional headers
$headers[] = 'To: Mary <mary@example.com>, Kelly <kelly@example.com>';
$headers[] = 'From: Birthday Reminder <birthday@example.com>';
$headers[] = 'Cc: birthdayarchive@example.com';
$headers[] = 'Bcc: birthdaycheck@example.com';

// Mail it
mail($to, $subject, $message, implode("\r\n", $headers));
?>
]]>
    </programlisting>
   </example>
  </para>
  <para>
   <note>
    <para>
     If intending to send HTML or otherwise Complex mails, it is recommended
     to use the PEAR package <link xlink:href="&url.pear.package;Mail_Mime">PEAR::Mail_Mime</link>.
    </para>
   </note>
  </para>
 </refsect1>

 <refsect1 role="notes">    
  &reftitle.notes;
  <note>
   <para>
    The SMTP implementation (Windows only) of <function>mail</function> differs in many
    ways from the sendmail implementation. First, it doesn't use a local binary
    for composing messages but only operates on direct sockets which means a
    <literal>MTA</literal> is needed listening on a network socket (which
    can either on the localhost or a remote machine).
   </para>
   <para>
    Second, the custom headers like
    <literal>From:</literal>,
    <literal>Cc:</literal>,
    <literal>Bcc:</literal> and
    <literal>Date:</literal> are
    <emphasis role="strong">not</emphasis> interpreted by the
    <literal>MTA</literal> in the first place, but are parsed by PHP.
   </para>
   <para>
    As such, the <parameter>to</parameter> parameter should not be an address
    in the form of &quot;Something &lt;someone@example.com&gt;&quot;. The
    mail command may not parse this properly while talking with 
    the MTA.
   </para>
  </note>
  
  <note>
   <para>
    It is worth noting that the <function>mail</function> function is not
    suitable for larger volumes of email in a loop. This function opens
    and closes an SMTP socket for each email, which is not very efficient.
   </para>
   <para>
    For the sending of large amounts of email, see the
    <link xlink:href="&url.pear.package;Mail">PEAR::Mail</link>, and
    <link xlink:href="&url.pear.package;Mail_Queue">PEAR::Mail_Queue</link> packages.
   </para>
  </note>

  <note>
   <para>
    The following RFCs may be useful:
    <link xlink:href="&url.rfc;1896">RFC 1896</link>,
    <link xlink:href="&url.rfc;2045">RFC 2045</link>,
    <link xlink:href="&url.rfc;2046">RFC 2046</link>,
    <link xlink:href="&url.rfc;2047">RFC 2047</link>,
    <link xlink:href="&url.rfc;2048">RFC 2048</link>,
    <link xlink:href="&url.rfc;2049">RFC 2049</link>, and
    <link xlink:href="&url.rfc;2822">RFC 2822</link>.
   </para>
  </note>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>mb_send_mail</function></member>
    <member><function>imap_mail</function></member>
    <member><link xlink:href="&url.pear.package;Mail">PEAR::Mail</link></member>
    <member><link xlink:href="&url.pear.package;Mail_Mime">PEAR::Mail_Mime</link></member>
   </simplelist>
  </para>
 </refsect1>
</refentry>
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