Technical information about QR Code Management for developers.
Shortcodes
[qrcm]
Displays a QR code image.
| Attribute | Description |
|---|---|
post_id | Display the QR code of the specified post |
user_id | Display the QR code of the specified user |
| (no attribute) | On a singular page, displays the QR code of the current post (only for post types enabled in the role settings); on an author archive, displays the QR code of that user |
[qrcm_scanner]
Displays a UI that reads a QR code with the camera and, after confirmation, redirects to the scanned URL. It has no attributes.
How the redirect works
When the redirect setting is enabled, QR codes embed a shortened URL of the form https://example.com/?qrc=CODE. The code is stored in the post meta / user meta rwc_qrcm_redirect_code. On access, the plugin records the scan in the {prefix}rwc_qrcm_log table and then redirects to the destination (the post permalink, or the user’s configured URL / author archive).
Access log table ({prefix}rwc_qrcm_log)
| Column | Description |
|---|---|
log_id | Sequence number |
post_id | Target post ID or user ID |
target_type | Target type (post / user). Added in 1.5.2 |
user_id | Visitor hash (stored in the rwc_qrcm_user_id cookie) |
create_date | Access date and time |
Options and metadata
| Data | Description |
|---|---|
Option rwc_qrcm | Values of the settings screen (display, data formats, roles, output, redirect) |
Option rwcqrcm | Default appearance of QR codes |
Option rwc_qrcm_db_version | Version used for DB migration |
Post / user meta rwcqrcm_qrdata_* | QR code data (URL, contact, event, free text) |
Post / user meta rwcqrcm_qrsettings_* | Per-post appearance settings |
Post / user meta rwc_qrcm_redirect_code | Code for the shortened URL |
QR code generation
QR codes are generated with the endroid/qr-code library (bundled with the plugin). The output formats are PNG / SVG / EPS / JPEG.
Uninstall
The plugin does not ship an uninstall script, so its options, metadata, and the access log table remain after the plugin is deleted. To remove them completely, delete the options, metadata, and table listed above manually.
Requirements
| WordPress | 4.7 or higher (tested up to 7.0) |
| PHP | 7.4 or higher |
| License | GPLv2 or later |