Send mail with attachment using PHP's mail function

// Create one file named "contact_us.php"

<form method="post" action="mail.php" enctype="multipart/form-data">
    <label>
        <span>Your Name</span>
        <input type="text" value="Jon Snow" name="s_name" />
    </label>
    <label>
        <span>Your Email</span>
        <input type="email" value=""  name="s_email" />
    </label>
    <label>
        <span>Message</span>
        <textarea name="s_message"></textarea>
    </label>
    <label>
        <span>Attachments</span>
        <!-- File input fields, you can add as many as required-->
        <input type="file" name="file[]" />
        <input type="file" name="file[]" />
        <input type="file" name="file[]" />
    </label>
    <label>
        <input type="submit" value="Send" />
    </label>
</form>

// Create one file named for action"mail.php"

<?php

if ($_POST && isset($_FILES['file'])) {

    $recipient_email = "demo@demo.com"; //recepient

    $from_email      = "demo@demo.com"; //from email using site domain.

    $subject         = "Attachment email from your website!"; //email subject line

    

    $sender_name    = filter_var($_POST["s_name"], FILTER_SANITIZE_STRING); //capture sender name

    $sender_email   = filter_var($_POST["s_email"], FILTER_SANITIZE_STRING); //capture sender email

    $sender_message = filter_var($_POST["s_message"], FILTER_SANITIZE_STRING); //capture message

    $attachments    = $_FILES['file'];

    

    //php validation

    if (strlen($sender_name) < 4) {

        die('Name is too short or empty');

    }

    if (!filter_var($sender_email, FILTER_VALIDATE_EMAIL)) {

        die('Invalid email');

    }

    if (strlen($sender_message) < 4) {

        die('Too short message! Please enter something');

    }

    

    $file_count = count($attachments['name']); //count total files attached

    $boundary   = md5("sanwebe.com");

    

    if ($file_count > 0) { //if attachment exists

        //header

        $headers = "MIME-Version: 1.0\r\n";

        $headers .= "From:" . $from_email . "\r\n";

        $headers .= "Reply-To: " . $sender_email . "" . "\r\n";

        $headers .= "Content-Type: multipart/mixed; boundary = $boundary\r\n\r\n";

        

        //message text

        $body = "--$boundary\r\n";

        $body .= "Content-Type: text/plain; charset=ISO-8859-1\r\n";

        $body .= "Content-Transfer-Encoding: base64\r\n\r\n";

        $body .= chunk_split(base64_encode($sender_message));

        

        //attachments

        for ($x = 0; $x < $file_count; $x++) {

            if (!empty($attachments['name'][$x])) {

                

                if ($attachments['error'][$x] > 0) //exit script and output error if we encounter any

                    {

                    $mymsg = array(

                        1 => "The uploaded file exceeds the upload_max_filesize directive in php.ini",

                        2 => "The uploaded file exceeds the MAX_FILE_SIZE directive that was specified in the HTML form",

                        3 => "The uploaded file was only partially uploaded",

                        4 => "No file was uploaded",

                        6 => "Missing a temporary folder"

                    );

                    die($mymsg[$attachments['error'][$x]]);

                }

                

                //get file info

                $file_name = $attachments['name'][$x];

                $file_size = $attachments['size'][$x];

                $file_type = $attachments['type'][$x];

                

                //read file 

                $handle  = fopen($attachments['tmp_name'][$x], "r");

                $content = fread($handle, $file_size);

                fclose($handle);

                $encoded_content = chunk_split(base64_encode($content)); //split into smaller chunks (RFC 2045)

                

                $body .= "--$boundary\r\n";

                $body .= "Content-Type: $file_type; name=\"$file_name\"\r\n";

                $body .= "Content-Disposition: attachment; filename=\"$file_name\"\r\n";

                $body .= "Content-Transfer-Encoding: base64\r\n";

                $body .= "X-Attachment-Id: " . rand(1000, 99999) . "\r\n\r\n";

                $body .= $encoded_content;

            }

        }

        

    } else { //send plain email otherwise

        $headers = "From:" . $from_email . "\r\n" . "Reply-To: " . $sender_email . "\n" . "X-Mailer: PHP/" . phpversion();

        $body    = $sender_message;

    }

    

    $sentMail = @mail($recipient_email, $subject, $body, $headers);

    if ($sentMail) //output success or failure messages

        {

        die('Thank you for your email');

    } else {

        die('Could not send mail! Please check your PHP mail configuration.');

    }

}

?>