QR codes

Every short link can have a QR code, and it works anywhere - the control panel, front-end templates, emails - because Short.io serves the image from a public URL.

How it works

Short.io's API reference describes POST /links/qr/{id} as returning image bytes. It doesn't. It returns JSON holding a URL on shortiougc.com, and that URL serves the PNG to anyone.

The authenticated call is what generates the image: fetching the URL before the API has been asked for it once returns 403. So the plugin calls it the first time a QR is needed for a link, caches the resulting URL for 30 days, and hands that URL out from then on.

The practical upshot is the nice one: a QR code is an ordinary remote image. No proxying, no data URIs, no signed URLs, and browsers and CDNs cache it like anything else.

In the control panel

Show in the entry sidebar gives you a small icon, a full image, or nothing. Either visible mode links through to a download.

The download goes through the plugin rather than linking straight at the image, because a browser ignores the download attribute on a cross-origin link - the file has to come from this origin to arrive as an attachment. That action needs the View short links permission and only serves links this site manages.

In templates

<img src="{{ craft.shortIo.qrUrl(entry) }}" alt="QR code">

qrSrc() is an alias, if that reads better to you. Both return null when the entry has no link, so guard them:

{% set qr = craft.shortIo.qrUrl(entry) %}
{% if qr %}
  <img src="{{ qr }}" alt="QR code for {{ entry.title }}" width="160">
{% endif %}

The first call for a given link makes one API request; after that it comes from the cache.

Styling

The Styling setting is a single row: size, foreground, background and format.

Things worth knowing, none of which match the API reference:

• Size is a scale factor from 1 to 99, not a pixel count.
• There is no margin option. Short.io does not offer one.
• Colours must be plain hex with no #. The control panel's colour picker stores #0ea5e9; the plugin strips the hash before sending, because Short.io validates against ^[0-9A-Fa-f]{6,8}$ and rejects the version with it.
• Setting either colour switches off Short.io's domain-level defaults automatically. Without that, custom colours are silently ignored.
• The image URL does not change when the styling does. Short.io regenerates the image behind the same URL, so a styling change can take a moment to appear and may sit behind browser caching.

Leave a cell blank to use whatever that domain is configured to do in Short.io itself.

Raw bytes

If you want the file rather than a URL - to attach to an email, or write into a volume:

{% set png = craft.shortIo.qrBytes(entry) %}

That fetches the public image server-side. It is a real HTTP request each time, so do not call it in a loop over a long list.

Caching

The image URL is cached for 30 days (QR cache). The image itself is cached by whatever sits in front of it - the browser, a CDN - exactly like any other remote image.