使用ElasticSearch搜索文件名

Question

我想使用ElasticSearch搜索文件名(而不是文件的内容).因此,我需要找到文件名的一部分(完全匹配,没有模糊搜索).

示例:
我有以下名称的文件:

My_first_file_created_at_2012.01.13.doc
My_second_file_created_at_2012.01.13.pdf
Another file.txt
And_again_another_file.docx
foo.bar.txt

现在我想搜索2012.01.13获取前两个文件.
搜索file或ile应返回除最后一个之外的所有文件名.

我如何使用ElasticSearch实现这一目标？

这是我测试过的,但它总是返回零结果:

curl -X DELETE localhost:9200/files
curl -X PUT    localhost:9200/files -d '
{
  "settings" : {
    "index" : {
      "analysis" : {
        "analyzer" : {
          "filename_analyzer" : {
            "type" : "custom",
            "tokenizer" : "lowercase",
            "filter"    : ["filename_stop", "filename_ngram"]
          }
        },
        "filter" : {
          "filename_stop" : {
            "type" : "stop",
            "stopwords" : ["doc", "pdf", "docx"]
          },
          "filename_ngram" : {
            "type" : "nGram",
            "min_gram" : 3,
            "max_gram" : 255
          }
        }
      }
    }
  },

  "mappings": {
    "files": {
      "properties": {
        "filename": {
          "type": "string",
          "analyzer": "filename_analyzer"
        }
      }
    }
  }
}
'

curl -X POST "http://localhost:9200/files/file" -d '{ "filename" : "My_first_file_created_at_2012.01.13.doc" }'
curl -X POST "http://localhost:9200/files/file" -d '{ "filename" : "My_second_file_created_at_2012.01.13.pdf" }'
curl -X POST "http://localhost:9200/files/file" -d '{ "filename" : "Another file.txt" }'
curl -X POST "http://localhost:9200/files/file" -d '{ "filename" : "And_again_another_file.docx" }'
curl -X POST "http://localhost:9200/files/file" -d '{ "filename" : "foo.bar.txt" }'
curl -X POST "http://localhost:9200/files/_refresh"


FILES='
http://localhost:9200/files/_search?q=filename:2012.01.13
'

for file in ${FILES}
do
  echo; echo; echo ">>> ${file}"
  curl "${file}&pretty=true"
done

Answer 1

你粘贴的内容有各种各样的问题:

1)映射不正确

创建索引时,指定:

"mappings": {
    "files": {

但你的类型实际上file不是files.如果您检查了映射,您会立即看到:

curl -XGET 'http://127.0.0.1:9200/files/_mapping?pretty=1' 

# {
#    "files" : {
#       "files" : {
#          "properties" : {
#             "filename" : {
#                "type" : "string",
#                "analyzer" : "filename_analyzer"
#             }
#          }
#       },
#       "file" : {
#          "properties" : {
#             "filename" : {
#                "type" : "string"
#             }
#          }
#       }
#    }
# }

2)分析仪定义不正确

您已指定了lowercasetokenizer但删除了任何非字母的内容(请参阅文档),因此您的数字将被完全删除.

您可以使用analyze API进行检查:

curl -XGET 'http://127.0.0.1:9200/_analyze?pretty=1&text=My_file_2012.01.13.doc&tokenizer=lowercase' 

# {
#    "tokens" : [
#       {
#          "end_offset" : 2,
#          "position" : 1,
#          "start_offset" : 0,
#          "type" : "word",
#          "token" : "my"
#       },
#       {
#          "end_offset" : 7,
#          "position" : 2,
#          "start_offset" : 3,
#          "type" : "word",
#          "token" : "file"
#       },
#       {
#          "end_offset" : 22,
#          "position" : 3,
#          "start_offset" : 19,
#          "type" : "word",
#          "token" : "doc"
#       }
#    ]
# }

3)关于搜索的Ngrams

您在索引分析器和搜索分析器中都包含了ngram标记过滤器.这对于索引分析器来说很好,因为你想要对ngram进行索引.但是当你搜索时,你想搜索完整的字符串,而不是每个ngram.

例如,如果"abcd"使用长度为1到4的ngrams进行索引,则最终会得到这些标记:

a b c d ab bc cd abc bcd

但是如果您搜索"dcba"(不应该匹配)并且您还使用ngrams分析搜索条件,那么您实际上是在搜索:

d c b a dc cb ba dbc cba

因此a,b,c和d将匹配!

解

首先,您需要选择合适的分析仪.您的用户可能会搜索单词,数字或日期,但他们可能不希望ile匹配file.相反,使用edge ngrams 可能会更有用,它会将ngram锚定到每个单词的开头(或结尾).

另外,为什么排除docx等？当然用户可能想要搜索文件类型？

因此,我们通过删除任何非字母或数字的东西(使用模式标记器)将每个文件名分解为较小的标记:

My_first_file_2012.01.13.doc
=> my first file 2012 01 13 doc

然后对于索引分析器,我们还将在每个令牌上使用edge ngrams:

my     => m my
first  => f fi fir firs first
file   => f fi fil file
2012   => 2 20 201 201
01     => 0 01
13     => 1 13
doc    => d do doc

我们创建索引如下:

curl -XPUT 'http://127.0.0.1:9200/files/?pretty=1'  -d '
{
   "settings" : {
      "analysis" : {
         "analyzer" : {
            "filename_search" : {
               "tokenizer" : "filename",
               "filter" : ["lowercase"]
            },
            "filename_index" : {
               "tokenizer" : "filename",
               "filter" : ["lowercase","edge_ngram"]
            }
         },
         "tokenizer" : {
            "filename" : {
               "pattern" : "[^\\p{L}\\d]+",
               "type" : "pattern"
            }
         },
         "filter" : {
            "edge_ngram" : {
               "side" : "front",
               "max_gram" : 20,
               "min_gram" : 1,
               "type" : "edgeNGram"
            }
         }
      }
   },
   "mappings" : {
      "file" : {
         "properties" : {
            "filename" : {
               "type" : "string",
               "search_analyzer" : "filename_search",
               "index_analyzer" : "filename_index"
            }
         }
      }
   }
}
'

现在,测试我们的分析仪是否正常工作:

filename_search:

curl -XGET 'http://127.0.0.1:9200/files/_analyze?pretty=1&text=My_first_file_2012.01.13.doc&analyzer=filename_search' 
[results snipped]
"token" : "my"
"token" : "first"
"token" : "file"
"token" : "2012"
"token" : "01"
"token" : "13"
"token" : "doc"

filename_index:

curl -XGET 'http://127.0.0.1:9200/files/_analyze?pretty=1&text=My_first_file_2012.01.13.doc&analyzer=filename_index' 
"token" : "m"
"token" : "my"
"token" : "f"
"token" : "fi"
"token" : "fir"
"token" : "firs"
"token" : "first"
"token" : "f"
"token" : "fi"
"token" : "fil"
"token" : "file"
"token" : "2"
"token" : "20"
"token" : "201"
"token" : "2012"
"token" : "0"
"token" : "01"
"token" : "1"
"token" : "13"
"token" : "d"
"token" : "do"
"token" : "doc"

好的 - 似乎工作正常.所以让我们添加一些文档:

curl -X POST "http://localhost:9200/files/file" -d '{ "filename" : "My_first_file_created_at_2012.01.13.doc" }'
curl -X POST "http://localhost:9200/files/file" -d '{ "filename" : "My_second_file_created_at_2012.01.13.pdf" }'
curl -X POST "http://localhost:9200/files/file" -d '{ "filename" : "Another file.txt" }'
curl -X POST "http://localhost:9200/files/file" -d '{ "filename" : "And_again_another_file.docx" }'
curl -X POST "http://localhost:9200/files/file" -d '{ "filename" : "foo.bar.txt" }'
curl -X POST "http://localhost:9200/files/_refresh"

并尝试搜索:

curl -XGET 'http://127.0.0.1:9200/files/file/_search?pretty=1'  -d '
{
   "query" : {
      "text" : {
         "filename" : "2012.01"
      }
   }
}
'

# {
#    "hits" : {
#       "hits" : [
#          {
#             "_source" : {
#                "filename" : "My_second_file_created_at_2012.01.13.pdf"
#             },
#             "_score" : 0.06780553,
#             "_index" : "files",
#             "_id" : "PsDvfFCkT4yvJnlguxJrrQ",
#             "_type" : "file"
#          },
#          {
#             "_source" : {
#                "filename" : "My_first_file_created_at_2012.01.13.doc"
#             },
#             "_score" : 0.06780553,
#             "_index" : "files",
#             "_id" : "ER5RmyhATg-Eu92XNGRu-w",
#             "_type" : "file"
#          }
#       ],
#       "max_score" : 0.06780553,
#       "total" : 2
#    },
#    "timed_out" : false,
#    "_shards" : {
#       "failed" : 0,
#       "successful" : 5,
#       "total" : 5
#    },
#    "took" : 4
# }

成功!

####更新####

我意识到搜索2012.01会匹配两者2012.01.12,2012.12.01所以我尝试更改查询以使用文本短语查询.但是,这不起作用.事实证明,边缘ngram滤波器增加了每个ngram的位置计数(虽然我认为每个ngram的位置将与单词的开头相同).

在点(3)中提到的问题使用时以上只是一个问题query_string,field或text查询它试图匹配任何令牌.但是,对于text_phrase查询,它会尝试匹配所有标记,并且顺序正确.

要演示此问题,请使用不同的日期索引另一个doc:

curl -X POST "http://localhost:9200/files/file" -d '{ "filename" : "My_third_file_created_at_2012.12.01.doc" }'
curl -X POST "http://localhost:9200/files/_refresh"

并进行与上述相同的搜索:

curl -XGET 'http://127.0.0.1:9200/files/file/_search?pretty=1'  -d '
{
   "query" : {
      "text" : {
         "filename" : {
            "query" : "2012.01"
         }
      }
   }
}
'

# {
#    "hits" : {
#       "hits" : [
#          {
#             "_source" : {
#                "filename" : "My_third_file_created_at_2012.12.01.doc"
#             },
#             "_score" : 0.22097087,
#             "_index" : "files",
#             "_id" : "xmC51lIhTnWplOHADWJzaQ",
#             "_type" : "file"
#          },
#          {
#             "_source" : {
#                "filename" : "My_first_file_created_at_2012.01.13.doc"
#             },
#             "_score" : 0.13137488,
#             "_index" : "files",
#             "_id" : "ZUezxDgQTsuAaCTVL9IJgg",
#             "_type" : "file"
#          },
#          {
#             "_source" : {
#                "filename" : "My_second_file_created_at_2012.01.13.pdf"
#             },
#             "_score" : 0.13137488,
#             "_index" : "files",
#             "_id" : "XwLNnSlwSeyYtA2y64WuVw",
#             "_type" : "file"
#          }
#       ],
#       "max_score" : 0.22097087,
#       "total" : 3
#    },
#    "timed_out" : false,
#    "_shards" : {
#       "failed" : 0,
#       "successful" : 5,
#       "total" : 5
#    },
#    "took" : 5
# }

第一个结果的日期2012.12.01不是最佳匹配2012.01.所以为了匹配那个确切的短语,我们可以这样做:

curl -XGET 'http://127.0.0.1:9200/files/file/_search?pretty=1'  -d '
{
   "query" : {
      "text_phrase" : {
         "filename" : {
            "query" : "2012.01",
            "analyzer" : "filename_index"
         }
      }
   }
}
'

# {
#    "hits" : {
#       "hits" : [
#          {
#             "_source" : {
#                "filename" : "My_first_file_created_at_2012.01.13.doc"
#             },
#             "_score" : 0.55737644,
#             "_index" : "files",
#             "_id" : "ZUezxDgQTsuAaCTVL9IJgg",
#             "_type" : "file"
#          },
#          {
#             "_source" : {
#                "filename" : "My_second_file_created_at_2012.01.13.pdf"
#             },
#             "_score" : 0.55737644,
#             "_index" : "files",
#             "_id" : "XwLNnSlwSeyYtA2y64WuVw",
#             "_type" : "file"
#          }
#       ],
#       "max_score" : 0.55737644,
#       "total" : 2
#    },
#    "timed_out" : false,
#    "_shards" : {
#       "failed" : 0,
#       "successful" : 5,
#       "total" : 5
#    },
#    "took" : 7
# }

或者,如果您仍想匹配所有3个文件(因为用户可能会记住文件名中的某些单词,但顺序错误),您可以运行这两个查询,但会增加文件名的重要性,这是正确的顺序:

curl -XGET 'http://127.0.0.1:9200/files/file/_search?pretty=1'  -d '
{
   "query" : {
      "bool" : {
         "should" : [
            {
               "text_phrase" : {
                  "filename" : {
                     "boost" : 2,
                     "query" : "2012.01",
                     "analyzer" : "filename_index"
                  }
               }
            },
            {
               "text" : {
                  "filename" : "2012.01"
               }
            }
         ]
      }
   }
}
'

# [Fri Feb 24 16:31:02 2012] Response:
# {
#    "hits" : {
#       "hits" : [
#          {
#             "_source" : {
#                "filename" : "My_first_file_created_at_2012.01.13.doc"
#             },
#             "_score" : 0.56892186,
#             "_index" : "files",
#             "_id" : "ZUezxDgQTsuAaCTVL9IJgg",
#             "_type" : "file"
#          },
#          {
#             "_source" : {
#                "filename" : "My_second_file_created_at_2012.01.13.pdf"
#             },
#             "_score" : 0.56892186,
#             "_index" : "files",
#             "_id" : "XwLNnSlwSeyYtA2y64WuVw",
#             "_type" : "file"
#          },
#          {
#             "_source" : {
#                "filename" : "My_third_file_created_at_2012.12.01.doc"
#             },
#             "_score" : 0.012931341,
#             "_index" : "files",
#             "_id" : "xmC51lIhTnWplOHADWJzaQ",
#             "_type" : "file"
#          }
#       ],
#       "max_score" : 0.56892186,
#       "total" : 3
#    },
#    "timed_out" : false,
#    "_shards" : {
#       "failed" : 0,
#       "successful" : 5,
#       "total" : 5
#    },
#    "took" : 4
# }