# Exclude Items by Default

The Exclude Items by Default feature allows folderish content types to omit child items from the REST API response. This avoids unnecessary catalog queries for blocks-based content where child items are already provided via Simplelayout blocks (`slblocks`).

## Overview

By default, the REST API response for any folderish content includes up to 25 child items. For blocks-based pages this is wasted computation — the frontend uses `slblocks` for rendering, not `items`.

When the `IExcludeItemsByDefault` behavior is active on a content type, the REST API serializer returns:

- `items`: empty list (`[]`)
- `items_total`: `0`
- `slblocks`: populated as usual

The exclusion can be overridden per-request with the query parameter `force_include_items=1`.

## REST API

### Default Response (items excluded)

```javascript
const response = await fetch('/Plone/my-page', {
    headers: { 'Accept': 'application/json' }
});
const data = await response.json();
console.log(data.items);        // []
console.log(data.items_total);  // 0
console.log(data.slblocks);     // [...] blocks still present
```

### Force Including Items

Pass `force_include_items=1` to bypass the exclusion and retrieve child items normally:

```javascript
const response = await fetch('/Plone/my-page?force_include_items=1', {
    headers: { 'Accept': 'application/json' }
});
const data = await response.json();
console.log(data.items);        // [{...}, {...}, ...]
console.log(data.items_total);  // 5
```

```python
import requests

response = requests.get(
    'http://localhost:8080/Plone/my-page',
    params={'force_include_items': '1'},
    headers={'Accept': 'application/json'}
)
data = response.json()
print(data['items'])
```

## Configuration

The behavior is opt-in. To activate it on a content type, add
`wcs.backend.content.behaviors.exclude_items.IExcludeItemsByDefault` to the
FTI's behaviors list via GenericSetup:

```xml
<object name="MyContentType" meta_type="Dexterity FTI">
  <property name="behaviors" purge="false">
    <element value="wcs.backend.content.behaviors.exclude_items.IExcludeItemsByDefault"/>
  </property>
</object>
```