如何在Elasticsearch PHP客户端中使用_script进行排序？

要在Elasticsearch PHP客户端中实现脚本排序，核心是把sort配置放在请求体（body数组）内，而不是作为顶级参数。你之前的错误在于将sort放在了$params的根节点，导致客户端把它解析成URL查询参数，而非请求体的一部分。

正确代码示例 #

$params = [
    'index' => self::INDEX_NAME,
    'from' => $offset,
    'size' => $pageSize,
    'body' => [
        // 将sort嵌套在body中，与query同级
        'sort' => [
            '_script' => [
                'type' => 'number',
                'script' => [
                    'source' => "doc['language'].value == 'en' ? 1 : 0"
                ],
                'order' => 'desc'
            ]
        ],
        'query' => [
            'bool' => [
                'must' => [
                    'multi_match' => [
                        'query' => $query,
                        'type' => 'best_fields',
                        'fields' => ['title', 'description', 'subject'],
                        'operator' => 'and'
                    ]
                ]
            ]
        ]
    ]
];

/**
 * @var ElasticResponse
 */
$response = $this->elasticClient->search($params);
$arrayResponse = $response->asArray();

错误原因说明 #

1. 顶级sort参数的问题：你最初把$params['sort']作为顶级参数时，PHP客户端会将其转换为URL查询参数（类似?sort=Array），这完全不符合Elasticsearch对脚本排序的结构要求，因此报出No mapping found for [Array] in order to sort on.。
2. JSON编码后仍放URL的问题：后来用json_encode处理sort参数，虽然序列化了结构，但依然放在URL中——复杂的脚本排序逻辑必须通过请求体传递，URL参数无法正确解析这种嵌套结构。

原问题背景 #

请问能否在Elasticsearch PHP客户端中使用_script进行排序？我尚未找到实现方法，但已通过cURL成功实现。

通过cURL执行查询的有效示例：

curl -X GET "localhost:9200/name/_search?pretty" -H 'Content-Type: application/json' -d'
{
  "query":{"bool":{"must":{"multi_match":{"query":"hello","type":"best_fields","fields":["title","description"],"operator":"and"}}}},
  "sort": {
    "_script": {
      "type": "number",
      "script": {
        "source": "doc[\u0027language\u0027].value == \u0027en\u0027 ? 1 : 0"
      },
      "order": "desc"
    }
  }
}
'

但使用PHP客户端时，sort参数会被添加到查询字符串而非请求体中，无法正常工作。

我首先尝试的代码：

$params = [
    'index' => self::INDEX_NAME,
    'from' => $offset,
    'size' => $pageSize,
    'body' => [],
];

$params['sort'] = ['_script' => ["script" => ["source" => "doc['language'].value == 'en' ? 1 : 0"], "type" => "number", "order" => "desc"]];

$params['body']['query']['bool']['must']['multi_match'] = [
    'query' => $query,
    'type' => 'best_fields',
    'fields' => [
        'title',
        'description',
        'subject',
    ],
    'operator' => 'and',
];


/**
 * @var ElasticResponse
 */
$response = $this->elasticClient->search($params);

$arrayResponse = $response->asArray();

结果报错：No mapping found for [Array] in order to sort on.

之后我尝试对sort参数进行编码：

$params['sort'] = json_encode(['_script' => ["script" => ["source" => "doc['language'].value == 'en' ? 1 : 0"], "type" => "number", "order" => "desc"]]);

此时sort参数出现在查询字符串中，仍无法正常工作：

POST http://localhost:9200/index/_search?sort=%7B%22_script%22%3A%7B%22script%22%3A%7B%22source%22%3A%22doc%5B%27language%27%5D.value+%3D%3D+%27en%27+%3F+1+%3A+0%22%7D%2C%22type%22%3A%22number%22%2C%22order%22%3A%22desc%22%7D%7D

请问有可行的解决方法吗？

内容的提问来源于stack exchange，提问作者Khriz