# Call to Action

The Call to Action (CTA) feature adds a single configurable action button to content. Editors give the button a label, a target link, a type (for example a regular link or a mail link) and decide whether it opens in a new window. The CTA data is exposed in the REST serialization of the content so the frontend can render the button.

## Overview

A CTA consists of:

- **cta_label** -- the visible button text.
- **cta_type** -- the kind of action, drawn from a configurable vocabulary (`Link` / `Mail` by default).
- **cta_href** -- the target link. Internal links stored as `resolveuid/...` are resolved to absolute URLs in the serialized output.
- **cta_new_window** -- whether the link should open in a new browser window/tab.

Label and link are coupled: a CTA must have either both a label and a link, or neither. A label without a link (or a link without a label) is rejected on save.


## REST API

The CTA fields appear directly in the serialized content. Render the button only when both `cta_label` and `cta_href` are present.

```http
GET /Plone/my-page HTTP/1.1
Host: localhost:8080
Accept: application/json
```

```json
{
    "@id": "http://localhost:8080/Plone/my-page",
    "cta_label": "Contact us",
    "cta_type": {
        "title": "Mail",
        "token": "mail"
    },
    "cta_href": "http://localhost:8080/Plone/contact-form",
    "cta_new_window": true
}
```

The fields:

- `cta_label` -- the button text, or `null` when unset.
- `cta_type` -- the selected type as a token/title object, or `null`. The default vocabulary offers `link` and `mail`.
- `cta_href` -- the resolved absolute target URL, or `null`. Internal `resolveuid` references are converted to absolute URLs before serialization.
- `cta_new_window` -- boolean; render the link with `target="_blank"` when `true`.

```javascript
const response = await fetch('/Plone/my-page', {
    headers: { 'Accept': 'application/json' }
});
const page = await response.json();

if (page.cta_label && page.cta_href) {
    const target = page.cta_new_window ? '_blank' : '_self';
    console.log(page.cta_label, page.cta_href, page.cta_type?.token, target);
}
```


## Configuration

The available CTA types come from a registry record:

`wcs.backend.content.cta.types`
A list of `Title:value` entries (title and value separated by a colon) that populate the `cta_type` vocabulary. The default set is `Link:link` and `Mail:mail`. Add entries here to offer editors additional action types; the chosen `value` is what appears as the token in the serialized `cta_type`.