AlgoliaEngine::map does not respect the order of the Engine results

[nunomaduro]

Context: Engines, like Algolia, allow to define the ranking - order of the results.

An example could be: I want products to be sorted by the quantity, so when I type "iphone" i want to get the ones that I have more in stock.

Problem: The method AlgoliaEngine::map does not return the models in the same order of the returned results by Algolia. Mainly because a whereIn is applied behind-the-scenes.

Solution: Sort the models by the same order of the given results just before returning the result of AlgoliaEngine::map.

[driesvints]

@nunomaduro I tried looking into this but I don't see how whereIn influences the order?

[nunomaduro]

The AlgoliaEngine::map will call the method getScoutModelsByIds from the trait Searchable.php.

The method getScoutModelsByIds will perform a Model::whereIn. The problem here: When you perform a regular $users = User::whereIn('id', [2,3,1])->get();, and assuming that you are using Mylsql, Eloquent will just tranform that in SELECT * FROM users WHERE id IN (2,3,1);. And mysql, be default, will return the rows in ID ascending order (1,2,3).

In this process you loose the order returned by the search engine.

# currently
$models = User::search('iphone')->get(); // search engine returns (2,3,1)
echo $models[0]->id // 1
echo $models[1]->id // 2
echo $models[2]->id // 3

# my proposal 
$models = User::search('iphone')->get(); // search engine returns (2,3,1)
echo $models[0]->id // 2
echo $models[1]->id // 3
echo $models[2]->id // 1

[obby-xiang]

AlgoliaEngine::map

        if (count($results['hits']) === 0) {
            return $model->newCollection();
        }

        $objectIds = collect($results['hits'])->pluck('objectID')->values()->all();

        return $model->getScoutModelsByIds(
            $builder, $objectIds
        )->filter(function ($model) use ($objectIds) {
            return in_array($model->getScoutKey(), $objectIds);
        })->sort(function ($modelA, $modelB) use ($objectIds) {
            //
            // sort
            //
            $indexA = array_search($modelA->getScoutKey(), $objectIds);
            $indexB = array_search($modelB->getScoutKey(), $objectIds);
            return $indexA == $indexB ? 0 : ($indexA < $indexB ? -1 : 1);
        });
        

[devinfd]

I can second this bug and I hope that you consider it critical. My search results are now in a seemingly random order. So basically the search results are useless. I can't see where this bug was introduced so I can't recommend a change. Sorry

[devinfd]

fyi: I had to implement an immediate fix so I overrode getScoutModelsByIds in my model with

return $query->whereIn(
            $this->getScoutKeyName(), $ids
        )->orderByRaw('FIELD('.$this->getScoutKeyName().', '.implode(', ', $ids).')')->get();

It's sloppy but it works

[nunomaduro]

@devinfd On Scout Extended this problem do not exists. Can you try see this source code https://github.com/algolia/scout-extended/blob/7935885de233a1d651e46f621b2c7ccce64da3fc/src/Searchable/ModelsResolver.php#L87 and perform a pull request to Laravel Scout?

[devinfd]

I can try that at some point. I'm away at conference and cant dedicate the time for at least a week.

[ChrisThompsonTLDR]

This should fix the issue.

    public function map(Builder $builder, $results, $model)
    {
        if (count($results['hits']) === 0) {
            return $model->newCollection();
        }

        $objectIds = collect($results['hits'])->pluck('objectID')->values()->all();

        return $model->getScoutModelsByIds(
                $builder, $objectIds
            )->filter(function ($model) use ($objectIds) {
                return in_array($model->getScoutKey(), $objectIds);
            })->sortBy(function($model) use ($objectIds) {
                return array_search($model->getScoutKey(), $objectIds);
            });
    }

[driesvints]

PR Made: #369