Event tickets in PDF with QR-code

The plugin Hello Event Ticket is a companion plugin to the Hello Event plugin. Without the use of the Hello Event Ticket plugin customers will receive a confirmation email generated by Woocommerce, but no specific ticket. When this plugin is installed they will also receive a ticket in PDF. The ticket contains various information about the event, plus a QR-code that links back to the site from where the ticket has been purchased.

Scanning the QR-code with a suitable mobile phone app or QR-code scanner able to bring a up a web page from a scanned URL will show a ticket handling page. Depending on the plugin settings and capabilities associated with the user, the ticket handling page can:

Indicate if the ticket has already been checked-in by the attendant(s)
Show information about the ticket: purchaser information, number of entries, date of purchase, etc.
If the ticket has not been checked-in: show a button for checking in the attendance
If the ticket has already been checked-in: show a button to re-activate the ticket for a new check in

In typical plugin settings all users will have access to 1 and 2, users with a first level of privileges (e.g. a subscriber role) will have access to 3, and users with further privileges (e.g. author or editor) will have access to 4.

Admin and shortcodes

The activation the plugin:

creates a database table to store information about tickets if it does not exist
creates a folder in the uploads directory to store QR-codes and tickets in PDF if it does not exist
creates a page with the slug hello-event-ticket-handler if it does not exist
adds a Tickets menu in the admin side-bar
adds a settings section to the admin side-bar

The plugin defines the following shortcodes:

hello-event-ticket-index	Used to show a list of tickets generated
hello-event-ticket-information	Used to show information about a ticket
hello-event-ticket-cancel	Used to show buttons for checking-in or re-activating a ticket

None of these shortcodes is necessary to use in normal operation.

The first shortcode makes it possible to show a list of tickets on the site front-end similar to what is shown in the admin area.

The next two shortcodes, which pick up an event-id from the URL parameter, appear on the automatically generated hello-event-ticket-handler page.