How do I select entries that have a particular block type?

Question

Say I have a channel with a matrix field which has two block types - text and video. Is there any way to select all entries in that channel that have a video block?

Idea 1

Use the Low Blocks plugin to query all video block types, then get their owner IDs, then use those to grab the entries.

Idea 2

Add a light switch field to the channel called "hasVideo". Update this field programmatically using the onSave event and a plugin. Then I can select all entries if hasVideo is true.

Is there a better way I'm missing?

Answer 1

You can write a custom plugin and make use of Craft's buildElementsQuery, to be able to add custom query statements to your ElementCriteriaModel.

Give your plugin a Template Variable addVideoBlockCriteria and with some lines of plugin code you will be able to do something like this from your template:

{% set criteria = craft.entries.section('blog').order('title asc') %}
{% set entries = craft.businesslogic.addVideoBlockCriteria(criteria) %}

{% for entry in entries %}
    ...
{% endfor %}

Make your Template Variable pass the criteria to a plugin service, run them through buildElementsQuery, and you can now modify the query with some DbCommands.

public function addVideoBlockCriteria(ElementCriteriaModel $criteria)
{
    $query = craft()->elements->buildElementsQuery($criteria);

    $query->andWhere('matrixcontent_article.field_video_videoUrl is not null');

    $query->join('matrixblocks matrixblocks', 'matrixblocks.ownerId = entries.id');
    $query->join('matrixcontent_article matrixcontent_article', 'matrixcontent_article.elementId = matrixblocks.id');

    $results = $query->queryAll();

    return EntryModel::populateModels($results);
}

Use join to bring in the "matrixblocks" table and also your Matrix field's content table "matrixcontent_mymatrixfield". And add the conditions with andWhere; the Matrix field's fields column names follow a scheme "field_myMatrixBlockType_myFieldInMatrixBlock".

Answer 2

Idea 2 [...] Add a light switch field to the channel called "hasVideo". Update this field programmatically using the onSave event and a plugin. Then I can select all entries if hasVideo is true.

If you're going to write your own plugin I would encourage you to implement carlcs' solution, which is a solid one, rather than going for what is basically a hack.

However, if you do decide to use Low Blocks instead and do the heavy lifting in your template, here's how that could work:

{# Get blocks, using the field ID, filtering by block type #}
{% set blocks = craft.lowblocks.blocks.fieldId(22).type('video') %}

{# Get entry IDs #}
{% set entryIds = [] %}
{% for block in blocks %}
    {% set entryId = block.owner.id %}
    {% set entryIds = entryIds|merge([entryId]) %}
{% endfor %}

{# Get entries #}
{% set entries = craft.entries({ id : entryIds }) %}

Not super elegant, but it should work. Personally I'm a big fan of keeping templates as logic-free and simple as possible, so I'd probably go for carlcs' solution, myself.

Note: Be sure to switch out the number 22 in my example Twig for the actual ID of your Matrix field.