python - 带有嵌套过滤器的Elasticsearch-dsl以及完全匹配的AND和OR条件

Question

前端有三个参数:

State-字符串

Categories-字符串数组。字符串可以包含几个单词。

Tags-与类别相似。

所有参数都是可选的。

如果传输了多个，则需要通过AND(以及state，category和tag的重合)实现它们的 bundle 包。如果提交了多个categories或tags，则至少匹配其中一个。

也就是说，如果请求到达时带有参数

{"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](具有至少一个请求的类别)。

不适合

state = Alabama, categories = category 1

state = Alaska, categories = 3

state = Alaska, categories = 1 category(类别名称应为1合1 "category 1" != "1 category")

为了发送elastikserch，我从python(3.7)发送请求。图书馆
elasticsearch-dsl

通过Q对象(在其中使用了match)收集了三个过滤器。

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

为elasticsearch创建了这样的请求。

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

为什么此逻辑查找的条目与的category / tag名称不完全相同？

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之间的关系-MTM
制图

{
  "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 bool(boolean) 查询。

在 bool(boolean) 查询ElasticSearch Boolean Query

您具有“必须”，它等同于“与”运算符。而“应该”充当“或”运算符。

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