通过PHP发送邮件：如果附件为空，如何发送邮件？

Question

Thanks to a wonderful tutorial by Agbonghama Collins , I've begun working on a WP plugin for my personal use, one that outputs a simple contact form with file attachments.

As for now, there are two file attachment fields, but they shouldn't be mandatory. However if either is left empty, the form outputs the following error:

WARNING: FILE_GET_CONTENTS() [FUNCTION.FILE-GET-CONTENTS]: FILENAME CANNOT BE EMPTY IN ~/SP-FORM-EXAMPLE.PHP ON LINE 55

The email ultimately does send, but arrives with two attachments anyway, either one or both of which is empty, depending on what was uploaded to the form. The following image depicts what it looks like if only one attachment was included:

For the file input fields, I'm calling the variable this way...

    if ( isset( $_POST['cf-submitted'] ) ) {

            ...

            $first_attachment = chunk_split(base64_encode(file_get_contents($_FILES['cf-attachment']['tmp_name'])));
            $first_filename = $_FILES['cf-extra_attachment']['name'];
            $second_attachment = chunk_split(base64_encode(file_get_contents($_FILES['cf-attachment']['tmp_name'])));
            $second_filename = $_FILES['cf-extra_attachment']['name'];

            ...

... and transmitting the mail as a MIME stream. So, my question is this: is there any way to allow these variables to be empty when the email is processed and sent, such that the appropriate number of attachments would be included in the sent the email and no error would be returned? Code examples would be helpful :)

And for clearer reference, here's the entire plugin file. It's very light and uses no helper scripts. Thank you all in advance!!

    <?php
/*
Plugin Name: Contact Form Plugin
Plugin URI: http://dbudell.com
Description: Modification to the "Simple non-bloated WordPress Contact Form" by Agbonghama Collins (http://w3guy.com); now allows for file attachments.
Version: 1.0
Author: Daniel Bogre Udell (@dbudell)
Author URI: http://dbudell.com
*/

function html_form_code() {
    echo '<form enctype="multipart/form-data" action="' . esc_url( $_SERVER['REQUEST_URI'] ) . '" method="post">';
    echo '<p>';
    echo 'Your Name (required) <br/>';
    echo '<input type="text" name="cf-name" pattern="[a-zA-Z0-9 ]+" value="' . ( isset( $_POST["cf-name"] ) ? esc_attr( $_POST["cf-name"] ) : '' ) . '" size="40" />';
    echo '</p>';
    echo '<p>';
    echo 'Your Email (required) <br/>';
    echo '<input type="email" name="cf-email" value="' . ( isset( $_POST["cf-email"] ) ? esc_attr( $_POST["cf-email"] ) : '' ) . '" size="40" />';
    echo '</p>';
    echo '<p>';
    echo 'Subject (required) <br/>';
    echo '<input type="text" name="cf-subject" pattern="[a-zA-Z ]+" value="' . ( isset( $_POST["cf-subject"] ) ? esc_attr( $_POST["cf-subject"] ) : '' ) . '" size="40" />';
    echo '</p>';
    echo '<p>';
    echo 'File Attachment (required)';
    echo '<input type="file" name="cf-attachment" size="40" />';
    echo '</p>';
    echo '<p>';
    echo 'Second File Attachment (required)';
    echo '<input type="file" name="cf-extra_attachment" size="40" />';
    echo '</p>';
    echo '<p>';
    echo 'Your Message (required) <br/>';
    echo '<textarea rows="10" cols="35" name="cf-message">' . ( isset( $_POST["cf-message"] ) ? esc_attr( $_POST["cf-message"] ) : '' ) . '</textarea>';
    echo '</p>';
    echo '<p><input type="submit" name="cf-submitted" value="Send"></p>';
    echo '</form>';
}

function deliver_mail() {

    // if the submit button is clicked, send the email
    if ( isset( $_POST['cf-submitted'] ) ) {

        // collect form values
        $name = sanitize_text_field( $_POST['cf-name'] );
        $email   = sanitize_email( $_POST['cf-email'] );
        $subject = sanitize_text_field( $_POST['cf-subject'] );
        $message = esc_textarea( $_POST['cf-message'] );
        $first_attachment = chunk_split(base64_encode(file_get_contents($_FILES['cf-attachment']['tmp_name'])));
        $first_filename = $_FILES['cf-attachment']['name'];
        $second_attachment = chunk_split(base64_encode(file_get_contents($_FILES['cf-extra_attachment']['tmp_name'])));
        $second_filename = $_FILES['cf-extra_attachment']['name'];

        $boundary =md5(date('r', time())); 

        $to = get_option( 'admin_email' );

        $headers = "From: $name <$email>" . "\r\n";
        $headers .= "\r\nMIME-Version: 1.0\r\nContent-Type: multipart/mixed; boundary=\"_1_$boundary\"";

        $message="This is a multi-part message in MIME format.

--_1_$boundary
Content-Type: multipart/alternative; boundary=\"_2_$boundary\"

--_2_$boundary
Content-Type: multipart/alternative; boundary=\"_3_$boundary\"

--_3_$boundary
Content-Type: text/plain; charset=\"utf-8\"
Content-Transfer-Encoding: 7bit

$message

--_3_$boundary--
--_2_$boundary
Content-Type: application/octet-stream; name=\"$first_filename\" 
Content-Transfer-Encoding: base64 
Content-Disposition: attachment 

$first_attachment
--_2_$boundary--

--_1_$boundary
Content-Type: application/octet-stream; name=\"$second_filename\" 
Content-Transfer-Encoding: base64 
Content-Disposition: attachment 

$second_attachment
--_1_$boundary--";

        // If email has been processed for sending, display a success message
        if ( wp_mail( $to, $subject, $message, $headers ) ) {
            echo '<div>';
            echo '<p>Thanks for contacting me, expect a response soon.</p>';
            echo '</div>';
        } else {
            echo 'An unexpected error occurred';
        }
    }
}

function cf_shortcode() {
    ob_start();
    deliver_mail();
    html_form_code();

    return ob_get_clean();
}

add_shortcode( 'test_contact_form', 'cf_shortcode' );

?>

Answer 1

Just check if the extra attachment is set and skip the part if not:

if(isset($_FILES['cf-extra_attachment']['tmp_name'])) {
    $second_attachment = chunk_split(base64_encode(file_get_contents($_FILES['cf-extra_attachment']['tmp_name'])));
    $second_filename = $_FILES['cf-extra_attachment']['name'];
}

Answer 2

to send attachements with wp_mail, try this

function deliver_mail() {

    // if the submit button is clicked, send the email
    if ( isset( $_POST['cf-submitted'] ) ) {

        // collect form values
        $name = sanitize_text_field( $_POST['cf-name'] );
        $email   = sanitize_email( $_POST['cf-email'] );
        $subject = sanitize_text_field( $_POST['cf-subject'] );
        $message = esc_textarea( $_POST['cf-message'] );


        $attachements = array();

        if (isset($_FILES['cf-attachment']['tmp_name'])) {
            $attachements[] = $_FILES['cf-attachment']['tmp_name'];
        }

        if (isset($_FILES['cf-extra_attachment']['tmp_name'])) {
            $attachements[] = $_FILES['cf-extra_attachment']['tmp_name'];
        }


        $to = get_option( 'admin_email' );

        $headers = "From: $name <$email>" . "\r\n";

        // If email has been processed for sending, display a success message
        if ( wp_mail( $to, $subject, $message, $headers, $attachements ) ) {
            echo '<div>';
            echo '<p>Thanks for contacting me, expect a response soon.</p>';
            echo '</div>';
        } else {
            echo 'An unexpected error occurred';
        }
    }
}

or another version with setting of the names of the attachements :

        add_action("phpmailer_init", function ($phpmailer) {

            if (isset($_FILES['cf-attachment']['tmp_name'])) {
                $phpmailer->addAttachment(
                    $_FILES['cf-attachment']['tmp_name']
                    , $_FILES['cf-attachment']['name']
                );
            }

            if (isset($_FILES['cf-extra_attachment']['tmp_name'])) {
                $phpmailer->addAttachment(
                    $_FILES['cf-extra_attachment']['tmp_name']
                    , $_FILES['cf-extra_attachment']['name']
                );
            }

        }, 10, 1);


        // If email has been processed for sending, display a success message
        if ( wp_mail( $to, $subject, $message, $headers) ) {
            echo '<div>';
            echo '<p>Thanks for contacting me, expect a response soon.</p>';
            echo '</div>';
        } else {
            echo 'An unexpected error occurred';
        }