Loupe

An SQLite based, PHP-only fulltext search engine.

Loupe…

• …only requires PHP and SQLite, you don't need anything else - no containers, no nothing
• …is typo-tolerant (based on the State Set Index Algorithm and Levenshtein)
• …supports phrase search using " quotation marks
• …supports filtering (and ordering) on any attribute with any SQL-inspired filter statement
• …supports filtering (and ordering) on Geo distance
• …orders relevance based on a typical TF-IDF Cosine similarity algorithm
• …auto-detects languages
• …supports stemming
• …is very easy to use
• …is all-in-all just the easiest way to replace your good old SQL LIKE %...% queries with a way better search experience but without all the hassle of an additional service to manage. SQLite is everywhere and all it needs is your filesystem.

Acknowledgement

If you are familiar with MeiliSearch, you will notice that the API is very much inspired by it. The reasons for this are simple:

1. First and foremost: I think, they did an amazing job of keeping configuration simple and understandable from a developer's perspective. Basic search tools shouldn't be complicated.
2. If Loupe shouldn't be enough for your use case anymore (you need advanced features, better performance etc.), switching to MeiliSearch instead should be as easy as possible.

I even took the liberty to copy some of their test data to feed Loupe for functional tests.

Usage

<?php

namespace App;

require_once 'vendor/autoload.php';

use Loupe\Loupe\Config\TypoTolerance;
use Loupe\Loupe\Configuration;
use Loupe\Loupe\LoupeFactory;
use Loupe\Loupe\SearchParameters;

$configuration = Configuration::create()
    ->withPrimaryKey('uuid') // optional, by default it's 'id'
    ->withSearchableAttributes(['firstname', 'lastname']) // optional, by default it's ['*'] - everything is indexed
    ->withFilterableAttributes(['departments', 'age'])
    ->withSortableAttributes(['lastname'])
    ->withTypoTolerance(TypoTolerance::create()->withFirstCharTypoCountsDouble(false)) // can be further fine-tuned but is enabled by default
;

$loupeFactory = new LoupeFactory();
$loupe = $loupeFactory->createInMemory($configuration);

// Persist your database:
// $loupe = $loupeFactory->create($dbPath, $configuration);


$loupe->addDocuments([
    [
        'uuid' => 2,
        'firstname' => 'Uta',
        'lastname' => 'Koertig',
        'departments' => [
            'Development',
            'Backoffice',
        ],
        'age' => 29,
    ],
    [
        'uuid' => 6,
        'firstname' => 'Huckleberry',
        'lastname' => 'Finn',
        'departments' => [
            'Backoffice',
        ],
        'age' => 18,
    ],
]);


$searchParameters = SearchParameters::create()
    ->withQuery('Gucleberry')
    ->withAttributesToRetrieve(['id', 'firstname'])
    ->withFilter("(departments = 'Backoffice' OR departments = 'Project Management') AND age > 17")
    ->withSort(['lastname:asc'])
;

$results = $loupe->search($searchParameters);

print_r($results->toArray());

/*
Array
(
    [hits] => Array
        (
            [0] => Array
                (
                    [firstname] => Huckleberry
                )

        )

    [query] => Gucleberry
    [processingTimeMs] => 4
    [hitsPerPage] => 20
    [page] => 1
    [totalPages] => 1
    [totalHits] => 1
)
*/

Docs

• Configuration.
• Searching.

"Why Loupe?" you ask? "Loupe" means "magnifier" in French and I felt like this was the appropriate choice for this library after having given my PHP crawler library a French name :-)