PHP Elasticsearch客户端使用function_score出现Unknown key报错求助

触发parsing_exception的核心原因是查询结构不符合Elasticsearch DSL规范：function_score是查询类型的一种，必须嵌套在请求体body下的query字段中，不能直接作为body的一级参数。

$client = ClientBuilder::create()->setHosts(['127.0.0.1:9200'])->build();
$params['index'] = 'providers_wow';

$params['body'] = [
    // 新增query层级包裹function_score
    'query' => [
        'function_score' => [
            'query' => [
                'multi_match' => [
                    'query' => $_GET['search'],
                    'fuzziness' => 2,
                    'fields' => ['services', 'specialities', 'full_name', 'primary_speciality']
                ]
            ],
            'score_mode' => 'multiply',
            'functions' => [
                [
                    'filter' => [
                        'term' => [
                            'node_type' => 'S'
                        ]
                    ],
                    'weight' => 4
                ],
                [
                    'filter' => [
                        'term' => [
                            'node_type' => 'SP'
                        ]
                    ],
                    'weight' => 5
                ],
                [
                    'filter' => [
                        'term' => [
                            'node_type' => 'P'
                        ]
                    ],
                    'weight' => 1
                ],
            ]
        ]
    ]
];
$params['from'] = 0;
$params['size'] = 100;
$params['_source'] = ["full_name", "services", "specialities", "node_type", "primary_speciality"];

$response = $client->search($params);

内容的提问来源于stack exchange，提问作者Umer Javed