How to provide a link to the filled PDF file to the user

In some situations it is necessary to provide a long-term download link to the filled PDF to the user (by email or other methods) after they have completed the contact form, instead of attaching the PDF to CF7 email message or providing a temporary download link in the form response.

There are a number of ways to provide the link to the user:

  1. Link in the email message the user receives after the user fills out the form
  2. Link on the thank you page that appears after the user fills out the form

The reason for needing to provide a link rather than attaching the filled PDF file to the sent email message might be the rather large size of the generated PDF file and the inability of email to handle large attachments.

The first step is to set up your form to save the filled PDFs at a specific path on your server.

The above option allows you to save your filled PDF files somewhere in the wp-content/uploads directory. Mail-tags can be used as part of the path. You have to make sure to use mail-tags that provide a unique path and/or filename. One option is to use the [_serial_number] mail-tag requires the Flamingo plugin). Set the save path option to my-pdfs/[_serial_number] and set the filename option to document. Your filled PDF file will be stored at wp-content/uploads/my-pdfs/#####/document.pdf (where ##### would be a unique sequence number). You can then provide a link to [_site_url]/wp-content/uploads/my-pdfs/[_serial_number]/document.pdf in your CF7 email message or form response message.

If you would like the link to be accessible only to the user who submitted the form then you can’t use the [_serial_number] mail-tag. You have to set it up in such a way that only the right user can guess the link. Make sure the save directory has indexing disabled and set the save path option to something that is hard to guess. You can either use mail-tags in the save path that contain some user-specific private information, such as [_user_login], or you can use Contact Form 7 Dynamic Text Extension plugin to create a mail-tag with a random number.

Link on a thank you page or elsewhere

Sometimes it is necessary to provide the download link to the filled PDF file from another page on your website, such as the thank you page that the user is redirected to after submitting the form.

You will need to create a tiny plugin that will create a CF7 special mail-tag and a WP shortcode. Both will output a “user session ID” that will be stored in user’s cookies. The filled PDF will be saved on the web server at a path that contains the session ID and the redirect page will link to that same location (via the shortcode).

<?php
/*
Plugin Name: CF7 special session id mail-tag and WP shortcode
Version:     0.1
*/

add_filter('wpcf7_special_mail_tags', 'wpcf7_session_id', 10, 3);
function wpcf7_session_id($output, $name, $html)
{
        if($name == '_session_id')
        {
                if(!isset($_COOKIE['wpcf7_session_id']))
                {
                        $id = uniqid();
                        setcookie('wpcf7_session_id', $id, time() + 24*60*60, "/");
                        $_COOKIE['wpcf7_session_id'] = $id;
                }
                $output = $_COOKIE['wpcf7_session_id'];
        }
        return $output;
}

add_shortcode('wpcf7_session_id', 'wpcf7_session_id_get');
function wpcf7_session_id_get()
{
        return isset($_COOKIE['wpcf7_session_id'])?$_COOKIE['wpcf7_session_id']:"";
}

You may want to create a folder called cf7-special-session-id in your wp-content/plugins directory and save the above code in a file called cf7-special-session-id.php inside the cf7-special-session-id folder. You will need to enable the newly created plugin on your plugins page.

To configure the CF7 form PDF attachment options, we will use the following:

Filename: document
Save PDF file on server: my-pdfs/[_session_id]/

To configure the redirect page, we will link our download button to the following URL:

/wp-content/uploads/my-pdfs/[wpcf7_session_id]/document.pdf

So, your thank you page HTML might contain the following:

<a href="/wp-content/uploads/my-pdfs/[wpcf7_session_id]/document.pdf" target="_blank" rel="noreferrer noopener">download</a>

The session ID will be created and stored in user’s cookies. Only that user will know the session ID, so, they are the only ones who will have access to the filled PDF, assuming that you don’t have directory indexing enabled and you don’t have any other way for them to find out other user’s session IDs.