Untitled

// Set $to to an hotmail.com or outlook.com email
$to = "YourEmail@hotmail.com";

$subject = 'wp_mail testing multipart';

$message = '------=_Part_18243133_1346573420.1408991447668
Content-Type: text/plain; charset=UTF-8

Hello world! This is plain text...


------=_Part_18243133_1346573420.1408991447668
Content-Type: text/html; charset=UTF-8

<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
</head>
<body>

<p>Hello World! This is HTML...</p>

</body>
</html>


------=_Part_18243133_1346573420.1408991447668--';

$headers = "MIME-Version: 1.0rn";
$headers .= "From: Foo <foo@bar.com>rn";
$headers .= 'Content-Type: multipart/alternative;boundary="----=_Part_18243133_1346573420.1408991447668"';


// send email
wp_mail( $to, $subject, $message, $headers );

add_filter( 'wp_mail_content_type', 'set_content_type' );
function set_content_type( $content_type ) {
    return 'multipart/alternative';
}

MIME-Version: 1.0
Content-Type: multipart/alternative;
         boundary="====f230673f9d7c359a81ffebccb88e5d61=="
MIME-Version: 1.0
Content-Type: multipart/alternative; charset=

// Set Content-Type and charset
    // If we don't have a content-type from the input headers
    if ( !isset( $content_type ) )
        $content_type = 'text/plain';

    /**
     * Filter the wp_mail() content type.
     *
     * @since 2.3.0
     *
     * @param string $content_type Default wp_mail() content type.
     */
    $content_type = apply_filters( 'wp_mail_content_type', $content_type );

    $phpmailer->ContentType = $content_type;

    // Set whether it's plaintext, depending on $content_type
    if ( 'text/html' == $content_type )
        $phpmailer->IsHTML( true );

    // If we don't have a charset from the input headers
    if ( !isset( $charset ) )
        $charset = get_bloginfo( 'charset' );

    // Set the content-type and charset

    /**
     * Filter the default wp_mail() charset.
     *
     * @since 2.3.0
     *
     * @param string $charset Default email charset.
     */
    $phpmailer->CharSet = apply_filters( 'wp_mail_charset', $charset );

    // Set custom headers
    if ( !empty( $headers ) ) {
        foreach( (array) $headers as $name => $content ) {
            $phpmailer->AddCustomHeader( sprintf( '%1$s: %2$s', $name, $content ) );
        }

        if ( false !== stripos( $content_type, 'multipart' ) && ! empty($boundary) )
            $phpmailer->AddCustomHeader( sprintf( "Content-Type: %s;nt boundary="%s"", $content_type, $boundary ) );
    }

    if ( !empty( $attachments ) ) {
        foreach ( $attachments as $attachment ) {
            try {
                $phpmailer->AddAttachment($attachment);
            } catch ( phpmailerException $e ) {
                continue;
            }
        }
    }

if ( false !== stripos( $content_type, 'multipart' ) && ! empty($boundary) ) {
    $phpmailer->ContentType = $content_type . "; boundary=" . $boundary;
}
else {

        $content_type = apply_filters( 'wp_mail_content_type', $content_type );

    $phpmailer->ContentType = $content_type;

    // Set whether it's plaintext, depending on $content_type
    if ( 'text/html' == $content_type )
        $phpmailer->IsHTML( true );

    // If we don't have a charset from the input headers
    if ( !isset( $charset ) )
        $charset = get_bloginfo( 'charset' );
}

// Set the content-type and charset

/**
 * Filter the default wp_mail() charset.
 *
 * @since 2.3.0
 *
 * @param string $charset Default email charset.
 */
$phpmailer->CharSet = apply_filters( 'wp_mail_charset', $charset );

// Set custom headers
if ( !empty( $headers ) ) {
    foreach( (array) $headers as $name => $content ) {
        $phpmailer->AddCustomHeader( sprintf( '%1$s: %2$s', $name, $content ) );
    }

}

/**
 * Send mail, similar to PHP's mail
 *
 * A true return value does not automatically mean that the user received the
 * email successfully. It just only means that the method used was able to
 * process the request without any errors.
 *
 * Using the two 'wp_mail_from' and 'wp_mail_from_name' hooks allow from
 * creating a from address like 'Name <email@address.com>' when both are set. If
 * just 'wp_mail_from' is set, then just the email address will be used with no
 * name.
 *
 * The default content type is 'text/plain' which does not allow using HTML.
 * However, you can set the content type of the email by using the
 * 'wp_mail_content_type' filter.
 *
 * If $message is an array, the key of each is used to add as an attachment
 * with the value used as the body. The 'text/plain' element is used as the
 * text version of the body, with the 'text/html' element used as the HTML
 * version of the body. All other types are added as attachments.
 *
 * The default charset is based on the charset used on the blog. The charset can
 * be set using the 'wp_mail_charset' filter.
 *
 * @since 1.2.1
 *
 * @uses PHPMailer
 *
 * @param string|array $to Array or comma-separated list of email addresses to send message.
 * @param string $subject Email subject
 * @param string|array $message Message contents
 * @param string|array $headers Optional. Additional headers.
 * @param string|array $attachments Optional. Files to attach.
 * @return bool Whether the email contents were sent successfully.
 */
function wp_mail( $to, $subject, $message, $headers = '', $attachments = array() ) {
    // Compact the input, apply the filters, and extract them back out

    /**
     * Filter the wp_mail() arguments.
     *
     * @since 2.2.0
     *
     * @param array $args A compacted array of wp_mail() arguments, including the "to" email,
     *                    subject, message, headers, and attachments values.
     */
    $atts = apply_filters( 'wp_mail', compact( 'to', 'subject', 'message', 'headers', 'attachments' ) );

    if ( isset( $atts['to'] ) ) {
        $to = $atts['to'];
    }

    if ( isset( $atts['subject'] ) ) {
        $subject = $atts['subject'];
    }

    if ( isset( $atts['message'] ) ) {
        $message = $atts['message'];
    }

    if ( isset( $atts['headers'] ) ) {
        $headers = $atts['headers'];
    }

    if ( isset( $atts['attachments'] ) ) {
        $attachments = $atts['attachments'];
    }

    if ( ! is_array( $attachments ) ) {
        $attachments = explode( "n", str_replace( "rn", "n", $attachments ) );
    }
    global $phpmailer;

    // (Re)create it, if it's gone missing
    if ( ! ( $phpmailer instanceof PHPMailer ) ) {
        require_once ABSPATH . WPINC . '/class-phpmailer.php';
        require_once ABSPATH . WPINC . '/class-smtp.php';
        $phpmailer = new PHPMailer( true );
    }

    // Headers
    if ( empty( $headers ) ) {
        $headers = array();
    } else {
        if ( !is_array( $headers ) ) {
            // Explode the headers out, so this function can take both
            // string headers and an array of headers.
            $tempheaders = explode( "n", str_replace( "rn", "n", $headers ) );
        } else {
            $tempheaders = $headers;
        }
        $headers = array();
        $cc = array();
        $bcc = array();

        // If it's actually got contents
        if ( !empty( $tempheaders ) ) {
            // Iterate through the raw headers
            foreach ( (array) $tempheaders as $header ) {
                if ( strpos($header, ':') === false ) {
                    if ( false !== stripos( $header, 'boundary=' ) ) {
                        $parts = preg_split('/boundary=/i', trim( $header ) );
                        $boundary = trim( str_replace( array( "'", '"' ), '', $parts[1] ) );
                    }
                    continue;
                }
                // Explode them out
                list( $name, $content ) = explode( ':', trim( $header ), 2 );

                // Cleanup crew
                $name    = trim( $name    );
                $content = trim( $content );

                switch ( strtolower( $name ) ) {
                    // Mainly for legacy -- process a From: header if it's there
                    case 'from':
                        $bracket_pos = strpos( $content, '<' );
                        if ( $bracket_pos !== false ) {
                            // Text before the bracketed email is the "From" name.
                            if ( $bracket_pos > 0 ) {
                                $from_name = substr( $content, 0, $bracket_pos - 1 );
                                $from_name = str_replace( '"', '', $from_name );
                                $from_name = trim( $from_name );
                            }

                            $from_email = substr( $content, $bracket_pos + 1 );
                            $from_email = str_replace( '>', '', $from_email );
                            $from_email = trim( $from_email );

                        // Avoid setting an empty $from_email.
                        } elseif ( '' !== trim( $content ) ) {
                            $from_email = trim( $content );
                        }
                        break;
                    case 'content-type':
                        if ( is_array($message) ) {
                            // Multipart email, ignore the content-type header
                            break;
                        }
                        if ( strpos( $content, ';' ) !== false ) {
                            list( $type, $charset_content ) = explode( ';', $content );
                            $content_type = trim( $type );
                            if ( false !== stripos( $charset_content, 'charset=' ) ) {
                                $charset = trim( str_replace( array( 'charset=', '"' ), '', $charset_content ) );
                            } elseif ( false !== stripos( $charset_content, 'boundary=' ) ) {
                                $boundary = trim( str_replace( array( 'BOUNDARY=', 'boundary=', '"' ), '', $charset_content ) );
                                $charset = '';
                            }

                        // Avoid setting an empty $content_type.
                        } elseif ( '' !== trim( $content ) ) {
                            $content_type = trim( $content );
                        }
                        break;
                    case 'cc':
                        $cc = array_merge( (array) $cc, explode( ',', $content ) );
                        break;
                    case 'bcc':
                        $bcc = array_merge( (array) $bcc, explode( ',', $content ) );
                        break;
                    default:
                        // Add it to our grand headers array
                        $headers[trim( $name )] = trim( $content );
                        break;
                }
            }
        }
    }

    // Empty out the values that may be set
    $phpmailer->ClearAllRecipients();
    $phpmailer->ClearAttachments();
    $phpmailer->ClearCustomHeaders();
    $phpmailer->ClearReplyTos();

    $phpmailer->Body= '';
    $phpmailer->AltBody= '';

    // From email and name
    // If we don't have a name from the input headers
    if ( !isset( $from_name ) )
        $from_name = 'WordPress';

    /* If we don't have an email from the input headers default to wordpress@$sitename
     * Some hosts will block outgoing mail from this address if it doesn't exist but
     * there's no easy alternative. Defaulting to admin_email might appear to be another
     * option but some hosts may refuse to relay mail from an unknown domain. See
     * https://core.trac.wordpress.org/ticket/5007.
     */

    if ( !isset( $from_email ) ) {
        // Get the site domain and get rid of www.
        $sitename = strtolower( $_SERVER['SERVER_NAME'] );
        if ( substr( $sitename, 0, 4 ) == 'www.' ) {
            $sitename = substr( $sitename, 4 );
        }

        $from_email = 'wordpress@' . $sitename;
    }

    /**
     * Filter the email address to send from.
     *
     * @since 2.2.0
     *
     * @param string $from_email Email address to send from.
     */
    $phpmailer->From = apply_filters( 'wp_mail_from', $from_email );

    /**
     * Filter the name to associate with the "from" email address.
     *
     * @since 2.3.0
     *
     * @param string $from_name Name associated with the "from" email address.
     */
    $phpmailer->FromName = apply_filters( 'wp_mail_from_name', $from_name );

    // Set destination addresses
    if ( !is_array( $to ) )
        $to = explode( ',', $to );

    foreach ( (array) $to as $recipient ) {
        try {
            // Break $recipient into name and address parts if in the format "Foo <bar@baz.com>"
            $recipient_name = '';
            if( preg_match( '/(.*)<(.+)>/', $recipient, $matches ) ) {
                if ( count( $matches ) == 3 ) {
                    $recipient_name = $matches[1];
                    $recipient = $matches[2];
                }
            }
            $phpmailer->AddAddress( $recipient, $recipient_name);
        } catch ( phpmailerException $e ) {
            continue;
        }
    }

    // If we don't have a charset from the input headers
    if ( !isset( $charset ) )
        $charset = get_bloginfo( 'charset' );

    // Set the content-type and charset

    /**
     * Filter the default wp_mail() charset.
     *
     * @since 2.3.0
     *
     * @param string $charset Default email charset.
     */
    $phpmailer->CharSet = apply_filters( 'wp_mail_charset', $charset );

    // Set mail's subject and body
    $phpmailer->Subject = $subject;

    if ( is_string($message) ) {
        $phpmailer->Body = $message;

        // Set Content-Type and charset
        // If we don't have a content-type from the input headers
        if ( !isset( $content_type ) )
            $content_type = 'text/plain';

        /**
         * Filter the wp_mail() content type.
         *
         * @since 2.3.0
         *
         * @param string $content_type Default wp_mail() content type.
         */
        $content_type = apply_filters( 'wp_mail_content_type', $content_type );

        $phpmailer->ContentType = $content_type;

        // Set whether it's plaintext, depending on $content_type
        if ( 'text/html' == $content_type )
            $phpmailer->IsHTML( true );

        // For backwards compatibility, new multipart emails should use
        // the array style $message. This never really worked well anyway
        if ( false !== stripos( $content_type, 'multipart' ) && ! empty($boundary) )
            $phpmailer->AddCustomHeader( sprintf( "Content-Type: %s;nt boundary="%s"", $content_type, $boundary ) );
    }
    elseif ( is_array($message) ) {
        foreach ($message as $type => $bodies) {
            foreach ((array) $bodies as $body) {
                if ($type === 'text/html') {
                    $phpmailer->Body = $body;
                }
                elseif ($type === 'text/plain') {
                    $phpmailer->AltBody = $body;
                }
                else {
                    $phpmailer->AddAttachment($body, '', 'base64', $type);
                }
            }
        }
    }

    // Add any CC and BCC recipients
    if ( !empty( $cc ) ) {
        foreach ( (array) $cc as $recipient ) {
            try {
                // Break $recipient into name and address parts if in the format "Foo <bar@baz.com>"
                $recipient_name = '';
                if( preg_match( '/(.*)<(.+)>/', $recipient, $matches ) ) {
                    if ( count( $matches ) == 3 ) {
                        $recipient_name = $matches[1];
                        $recipient = $matches[2];
                    }
                }
                $phpmailer->AddCc( $recipient, $recipient_name );
            } catch ( phpmailerException $e ) {
                continue;
            }
        }
    }

    if ( !empty( $bcc ) ) {
        foreach ( (array) $bcc as $recipient) {
            try {
                // Break $recipient into name and address parts if in the format "Foo <bar@baz.com>"
                $recipient_name = '';
                if( preg_match( '/(.*)<(.+)>/', $recipient, $matches ) ) {
                    if ( count( $matches ) == 3 ) {
                        $recipient_name = $matches[1];
                        $recipient = $matches[2];
                    }
                }
                $phpmailer->AddBcc( $recipient, $recipient_name );
            } catch ( phpmailerException $e ) {
                continue;
            }
        }
    }

    // Set to use PHP's mail()
    $phpmailer->IsMail();

    // Set custom headers
    if ( !empty( $headers ) ) {
        foreach ( (array) $headers as $name => $content ) {
            $phpmailer->AddCustomHeader( sprintf( '%1$s: %2$s', $name, $content ) );
        }
    }

    if ( !empty( $attachments ) ) {
        foreach ( $attachments as $attachment ) {
            try {
                $phpmailer->AddAttachment($attachment);
            } catch ( phpmailerException $e ) {
                continue;
            }
        }
    }

    /**
     * Fires after PHPMailer is initialized.
     *
     * @since 2.2.0
     *
     * @param PHPMailer &$phpmailer The PHPMailer instance, passed by reference.
     */
    do_action_ref_array( 'phpmailer_init', array( &$phpmailer ) );

    // Send!
    try {
        return $phpmailer->Send();
    } catch ( phpmailerException $e ) {
        return false;
    }
}

// Set $to to an hotmail.com or outlook.com email
$to = "YourEmail@hotmail.com";

$subject = 'wp_mail testing multipart';

$message['text/plain'] = 'Hello world! This is plain text...';
$message['text/html'] = '<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
</head>
<body>

<p>Hello World! This is HTML...</p>

</body>
</html>';

add_filter( 'wp_mail_from', $from_func = function ( $from_email ) { return 'foo@bar.com'; } );
add_filter( 'wp_mail_from_name', $from_name_func = function ( $from_name ) { return 'Foo'; } );

// send email
wp_mail( $to, $subject, $message );

remove_filter( 'wp_mail_from', $from_func );
remove_filter( 'wp_mail_from_name', $from_name_func );

public function getMailMIME()
{
    $result = '';
    $ismultipart = true;
    switch ($this->message_type) {
        case 'inline':
            $result .= $this->headerLine('Content-Type', 'multipart/related;');
            $result .= $this->textLine("tboundary="" . $this->boundary[1] . '"');
            break;
        case 'attach':
        case 'inline_attach':
        case 'alt_attach':
        case 'alt_inline_attach':
            $result .= $this->headerLine('Content-Type', 'multipart/mixed;');
            $result .= $this->textLine("tboundary="" . $this->boundary[1] . '"');
            break;
        case 'alt':
        case 'alt_inline':
            $result .= $this->headerLine('Content-Type', 'multipart/alternative;');
            $result .= $this->textLine("tboundary="" . $this->boundary[1] . '"');
            break;
        default:
            // Catches case 'plain': and case '':
            $result .= $this->textLine('Content-Type: ' . $this->ContentType . '; charset=' . $this->CharSet);
            $ismultipart = false;
            break;
    }

protected function setMessageType()
{
    $type = array();
    if ($this->alternativeExists()) {
        $type[] = 'alt';
    }
    if ($this->inlineImageExists()) {
        $type[] = 'inline';
    }
    if ($this->attachmentExists()) {
        $type[] = 'attach';
    }
    $this->message_type = implode('_', $type);
    if ($this->message_type == '') {
        $this->message_type = 'plain';
    }
}

public function alternativeExists()
{
    return !empty($this->AltBody);
}

add_action('phpmailer_init','wp_mail_set_text_body');
function wp_mail_set_text_body($phpmailer) {
     if (empty($phpmailer->AltBody)) {$phpmailer->AltBody = strip_tags($phpmailer->Body);}
}

$message ='<html>
 <head>
     <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
 </head>
 <body>
     <p>Hello World! This is HTML...</p>
 </body>
 </html>';

 wp_mail($to,$subject,$message);

add_action( 'phpmailer_init', array($this->mailer, 'send_email' ) );

/**
* Modify php mailer body with final email
*
* @since 1.0.0
* @param object $phpmailer
*/
function send_email( $phpmailer ) {

    $message            =  $this->add_template( apply_filters( 'mailtpl/email_content', $phpmailer->Body ) );
    $phpmailer->AltBody =  $this->replace_placeholders( strip_tags($phpmailer->Body) );
    $phpmailer->Body    =  $this->replace_placeholders( $message );
}

add_action( 'phpmailer_init', 'phpmailer_init' );

//http://wordpress.stackexchange.com/a/191974
//http://stackoverflow.com/a/2564472
function phpmailer_init( $phpmailer )
{
  if( $phpmailer->ContentType == 'text/html' ) {
    $phpmailer->AltBody = Html2TextHtml2Text::convert( $phpmailer->Body );
  }
}

/* setting the message parts for wp_mail()*/
$markup = array();
$markup['html'] = '<html>some html</html>';
$markup['plaintext'] = 'some plaintext';
/* message we are sending */
$message = maybe_serialize($markup);


/* setting alt body distinctly */
add_action('phpmailer_init', array($this, 'set_alt_mail_body'));

function set_alt_mail_body($phpmailer){
    if( $phpmailer->ContentType == 'text/html' ) {
        $body_parts = maybe_unserialize($phpmailer->Body);

        if(!empty($body_parts['html'])){
            $phpmailer->MsgHTML($body_parts['html']);
        }

        if(!empty($body_parts['plaintext'])){
            $phpmailer->AltBody = $body_parts['plaintext'];
        }
    }
}

<?php

$to = '';
$subject = '';
$from = '';
$body = 'The text html content, <html>...';

$headers = "FROM: {$from}";

add_action( 'phpmailer_init', function () {
    global $phpmailer;
    $phpmailer->AltBody = 'The text plain content of your original text html content.';
} );

wp_mail($to, $subject, $body, $headers);