pdoTools integration

Sort and list resources, products, and other objects by reactions with a leftJoin on the ReactionAggregate model.

leftJoin: JSON and Fenom

pdoTools accepts leftJoin as an array or a JSON string. In JSON, escape the model class as "Reactions\\Model\\ReactionAggregate" (two \ characters before Model in the final string).

Approach	Example
MODX tag	"class":"Reactions\\\\Model\\\\ReactionAggregate" — four \ in the template, two remain in JSON
Fenom	array 'class' => 'Reactions\Model\ReactionAggregate' — preferred, no JSON
PHP / snippet	'class' => ReactionAggregate::class or a join array

If the JSON is invalid, json_decode in msProducts/pdoResources silently skips the join. Then the log shows:

Unknown column 'Aggregate.likes' in 'order clause'

msProducts and ONLY_FULL_GROUP_BY

msProducts always groups by msProduct.id. On MySQL with ONLY_FULL_GROUP_BY you cannot sort by plain Aggregate.likes — use an aggregate:

&sortby=MAX(Aggregate.likes)`` or 'sortby' => 'MAX(Aggregate.likes)'

For pdoResources without GROUP BY, Aggregate.likes is enough.

ReactionAggregate model

The reactions_aggregates table stores precomputed metrics:

Field	Description
object_class	Object class (modResource, msProduct, …)
object_id	Object ID
context	MODX context
counts	JSON with per-type counters
likes	Sum of like + up
dislikes	Sum of dislike + down
rating	likes − dislikes
total	Sum of all reactions
trending_score	Trending score

Sort resources by likes

modx

[[!pdoResources?
    &parents=`0`
    &depth=`10`
    &limit=`12`
    &leftJoin=`{"Aggregate":{"class":"Reactions\\\\Model\\\\ReactionAggregate","on":"Aggregate.object_id = modResource.id AND Aggregate.object_class = 'modResource' AND Aggregate.context = 'web'"}}`
    &sortby=`Aggregate.likes`
    &sortdir=`DESC`
    &tpl=`tpl.article.card`
]]

fenom

{'!pdoResources' | snippet : [
    'parents' => 0,
    'depth' => 10,
    'limit' => 12,
    'leftJoin' => [
        'Aggregate' => [
            'class' => 'Reactions\Model\ReactionAggregate',
            'on' => "Aggregate.object_id = modResource.id AND Aggregate.object_class = 'modResource' AND Aggregate.context = 'web'",
        ],
    ],
    'sortby' => 'Aggregate.likes',
    'sortdir' => 'DESC',
    'tpl' => 'tpl.article.card',
]}

Sort by rating

modx

[[!pdoResources?
    &parents=`5`
    &leftJoin=`{"Aggregate":{"class":"Reactions\\\\Model\\\\ReactionAggregate","on":"Aggregate.object_id = modResource.id AND Aggregate.object_class = 'modResource'"}}`
    &sortby=`Aggregate.rating`
    &sortdir=`DESC`
    &limit=`10`
]]

fenom

{'!pdoResources' | snippet : [
    'parents' => 5,
    'leftJoin' => [
        'Aggregate' => [
            'class' => 'Reactions\Model\ReactionAggregate',
            'on' => "Aggregate.object_id = modResource.id AND Aggregate.object_class = 'modResource'",
        ],
    ],
    'sortby' => 'Aggregate.rating',
    'sortdir' => 'DESC',
    'limit' => 10,
]}

Sort by trending

modx

[[!pdoResources?
    &parents=`0`
    &leftJoin=`{"Aggregate":{"class":"Reactions\\\\Model\\\\ReactionAggregate","on":"Aggregate.object_id = modResource.id AND Aggregate.object_class = 'modResource'"}}`
    &sortby=`Aggregate.trending_score`
    &sortdir=`DESC`
    &limit=`8`
]]

fenom

{'!pdoResources' | snippet : [
    'parents' => 0,
    'leftJoin' => [
        'Aggregate' => [
            'class' => 'Reactions\Model\ReactionAggregate',
            'on' => "Aggregate.object_id = modResource.id AND Aggregate.object_class = 'modResource'",
        ],
    ],
    'sortby' => 'Aggregate.trending_score',
    'sortdir' => 'DESC',
    'limit' => 8,
]}

Counters in the pdoResources chunk

In the tpl.article.card chunk:

modx

<h3>[[+pagetitle]]</h3>
<p>👍 [[!ReactionsCount? &object=`[[+id]]` &format=`{LIKES}`]]</p>

fenom

<h3>{$pagetitle}</h3>
<p>👍 {'!ReactionsCount' | snippet : ['object' => $id, 'format' => '{LIKES}']}</p>

Or via a placeholder:

modx

[[!ReactionsCount? &object=`[[+id]]` &format=`{LIKES}` &toPlaceholder=`likes_[[+id]]`]]
<span>[[+likes_[[+id]]]]</span>

fenom

{'!ReactionsCount' | snippet : [
    'object' => $id,
    'format' => '{LIKES}',
    'toPlaceholder' => ('likes_' ~ $id),
]}
<span>{$_modx->getPlaceholder('likes_' ~ $id)}</span>

List with pdoPage

modx

[[!pdoPage?
    &element=`pdoResources`
    &parents=`0`
    &leftJoin=`{"Aggregate":{"class":"Reactions\\\\Model\\\\ReactionAggregate","on":"Aggregate.object_id = modResource.id AND Aggregate.object_class = 'modResource'"}}`
    &sortby=`Aggregate.likes`
    &sortdir=`DESC`
    &tpl=`tpl.article.card`
]]
[[!+page.nav]]

fenom

{'!pdoPage' | snippet : [
    'element' => 'pdoResources',
    'parents' => 0,
    'leftJoin' => [
        'Aggregate' => [
            'class' => 'Reactions\Model\ReactionAggregate',
            'on' => "Aggregate.object_id = modResource.id AND Aggregate.object_class = 'modResource'",
        ],
    ],
    'sortby' => 'Aggregate.likes',
    'sortdir' => 'DESC',
    'tpl' => 'tpl.article.card',
]}
{$_modx->getPlaceholder('page.nav')}

In a list row template (chunk tpl / $results loop):

modx

<article>
    <h2><a href="[[~[[+id]]]]">[[+pagetitle]]</a></h2>
    [[!ReactionsCount?
        &object=`[[+id]]`
        &format=`👍 {LIKES}`
    ]]
</article>

fenom

{foreach $results as $row}
    <article>
        <h2><a href="{$row.id | url}">{$row.pagetitle}</a></h2>
        {'!ReactionsCount' | snippet : [
            'object' => $row.id,
            'format' => '👍 {LIKES}',
        ]}
    </article>
{/foreach}

Filter: only objects with reactions

modx

[[!pdoResources?
    &parents=`0`
    &leftJoin=`{"Aggregate":{"class":"Reactions\\\\Model\\\\ReactionAggregate","on":"Aggregate.object_id = modResource.id AND Aggregate.object_class = 'modResource'"}}`
    &where=`{"Aggregate.likes:>":0}`
    &sortby=`Aggregate.likes`
    &sortdir=`DESC`
]]

fenom

{'!pdoResources' | snippet : [
    'parents' => 0,
    'leftJoin' => [
        'Aggregate' => [
            'class' => 'Reactions\Model\ReactionAggregate',
            'on' => "Aggregate.object_id = modResource.id AND Aggregate.object_class = 'modResource'",
        ],
    ],
    'where' => '{"Aggregate.likes:>":0}',
    'sortby' => 'Aggregate.likes',
    'sortdir' => 'DESC',
]}

Notes

• Make sure the Reactions package is registered in xPDO: the ReactionAggregate class is available under the full name Reactions\Model\ReactionAggregate.
• If an object has no aggregate, leftJoin returns NULL. Those rows end up last with DESC or first with ASC.
• After a bulk import of reactions, run php core/components/reactions/cli.php recount.