具有嵌套过滤器和 AND 和 OR 条件的 Elasticsearch-dsl 完全匹配

Question

三个参数来自前端：

1. State - 字符串
2. Categories - 一个字符串数组。字符串可以由多个单词组成。
3. Tags - 类似于类别。

所有参数都是可选的。

如果是多个传输，需要通过AND来实现它们的bundle（和state、category、tag的巧合）。 如果提交了多个categories 或tags，则会为其中至少一个进行匹配。

也就是说，如果一个带有参数的请求到达

{"state": "Alaska", "categories": ["category 1", "category 2"]}

答案将是

• state = Alaska，categories = category 1；
• state = Alaska, categories = category 2;
• state = Alaska, categories = [category 1, category 2];
• state = Alaska, categories = [category 1, category 3]（至少有一个要求的类别）。

不适合

• state = Alabama, categories = category 1
• state = Alaska, categories = 3
• state = Alaska, categories = 1 category（类别名称应该是 1-in-1"category 1" != "1 category"）

到elastikserch 我从python (3.7) 发送请求。拿了一个图书馆 elasticsearch-dsl

通过Q 对象收集三个过滤器（在其中使用match）。

combined_filter = state_filter & categories_filter & tags_filter

categories和tags的列表分为subfilters through OR。

query = queries.pop()
for item in queries:
    query |= item

这样的请求是为elasticsearch 创建的。

Bool(minimum_should_match=1, 
    must=[Match(state='Alaska'), MatchAll()], 
    should=[Match(categories='category 1'), Match(categories='category 2')]
)

为什么这个逻辑通过不准确 category / tag 名称查找条目？

from typing import List

from elasticsearch import Elasticsearch
from elasticsearch_dsl import Q, Search
from flask import request
from flask.views import MethodView


es = Elasticsearch()


class ArticleSearchAPIView(MethodView):
    """
    Search articles using ElasticSearch
    """

    @staticmethod
    def filter_create(queries: List[Q]) -> Q:
        """
        Creates Q.OR filter
        """
        query = queries.pop()
        for item in queries:
            query |= item
        return query

    def get(self) -> dict:
        """
        Search article
        First request - with empty params
        """
        search = Search(using=es, index=ArticleModel.__tablename__)
        state_filter = categories_filter = tags_filter = Q()
        result = "Articles not found."

        data = request.get_json()
        categories = data.get("categories")
        tags = data.get("tags")
        state = data.get("state")

        if state:
            state_filter = Q("match", state=state)

        if categories:
            queries = [Q("match", categories=value) for value in categories]
            categories_filter = self.filter_create(queries)

        if tags:
            queries = [Q("match", tags=value) for value in tags]
            tags_filter = self.filter_create(queries)

        combined_filter = state_filter & categories_filter & tags_filter
        found = (
            search.filter(combined_filter)
            .execute()
            .to_dict()["hits"]
            .get("hits")
        )

        if found:
            result = [article["_source"] for article in found]
        return {"response": result}

更新

---

Article and Category 和 Article and Tag - MTM 之间的关系

映射

{
  "articles": {
    "mappings": {
      "properties": {
        ...
        "categories": {
          "type": "text",
          "fields": {
            "keyword": {
              "type": "keyword",
              "ignore_above": 256
            }
          }
        },
        "state": {
          "type": "text",
          "fields": {
            "keyword": {
              "type": "keyword",
              "ignore_above": 256
            }
          }
        },
        "tags": {
          "type": "text",
          "fields": {
            "keyword": {
              "type": "keyword",
              "ignore_above": 256
            }
          }
        }
        ...
      }
    }
  }
}

Answer 1

您可以使用布尔查询。

在布尔查询ElasticSearch Boolean Query

你有 'must' 相当于 'AND' 运算符。和 'should' 充当 'OR' 运算符。

{
  "query": {
    "bool" : {
      "must" : {
        "term" : { "user" : "kimchy" }
      },
      "should" : [
        { "term" : { "tag" : "wow" } },
        { "term" : { "tag" : "elasticsearch" } }
      ],
    }
  }
}

Answer 2

我认为这里不需要使用elasticsearch-dsl。

这是我的决定。

from typing import Dict, List, Tuple, Union

from elasticsearch import Elasticsearch
from flask import request
from flask.views import MethodView

from .models import AticleModel  # ArticleModel.__tablename__ == "articles"


es = Elasticsearch()


class ArticleSearchAPIView(MethodView):
    """
    Search articles using ElasticSearch
    """

    def get(
        self,
    ) -> Union[
        Dict[str, Union[list, List[str]]],
        Tuple[Dict[str, str], int],
        Dict[str, Union[list, str]],
    ]:
        """
        Search articles
        """
        data = request.get_json()
        categories = data.get("categories")
        tags = data.get("tags")
        state = data.get("state")
        result = "Articles not found."

        query = {"bool": {"must": []}}
        if state:
            query["bool"]["must"].append({"term": {"state.keyword": state}})
        if categories:
            query["bool"]["must"].append(
                {"terms": {"categories.keyword": categories}}
            )
        if tags:
            query["bool"]["must"].append({"terms": {"tags.keyword": tags}})

        found = es.search(
            index=ArticleModel.__tablename__, body={"query": query},
        )["hits"].get("hits")

        if found:
            result = [article["_source"] for article in found]
        return {"response": result}