ElasticSearch &附件类型(NEST C#) [英] ElasticSearch & attachment type (NEST C#)

问题描述

我正在尝试使用 elasticsearch/NEST 为 pdf 文档编制索引.

I'm trying to index a pdf document with elasticsearch/NEST.

文件已编入索引，但搜索结果返回 0 个命中.

The file is indexed but search results returns with 0 hits.

我需要搜索结果只返回文档Id和高亮结果

I need the search result to return only the document Id and the highlight result

(不含 base64 内容)

(without the base64 content)

代码如下:

我将不胜感激，

谢谢，

class Program
{
    static void Main(string[] args)
    {
        // create es client
        string index = "myindex";

        var settings = new ConnectionSettings("localhost", 9200)
            .SetDefaultIndex(index);
        var es = new ElasticClient(settings);

        // delete index if any
        es.DeleteIndex(index);

        // index document
        string path = "test.pdf";
        var doc = new Document()
        {
            Id = 1,
            Title = "test",
            Content = Convert.ToBase64String(File.ReadAllBytes(path))
        };

        var parameters = new IndexParameters() { Refresh = true };
        if (es.Index<Document>(doc, parameters).OK)
        {
            // search in document
            string query = "semantic"; // test.pdf contains the string "semantic"

            var result = es.Search<Document>(s => s
                .Query(q =>
                    q.QueryString(qs => qs
                        .Query(query)
                    )
                )
                .Highlight(h => h
                    .PreTags("<b>")
                    .PostTags("</b>")
                    .OnFields(
                      f => f
                        .OnField(e => e.Content)
                        .PreTags("<em>")
                        .PostTags("</em>")
                    )
                )
            );

            if (result.Hits.Total == 0)
            {
            }
        }
    }
}

[ElasticType(
    Name = "document",
    SearchAnalyzer = "standard",
    IndexAnalyzer = "standard"
)]
public class Document
{
    public int Id { get; set; }

    [ElasticProperty(Store = true)]
    public string Title { get; set; }

    [ElasticProperty(Type = FieldType.attachment,
        TermVector = TermVectorOption.with_positions_offsets)]
    public string Content { get; set; }
}

推荐答案

安装附件插件并重启ES

Install the Attachment Plugin and restart ES

bin/plugin -install elasticsearch/elasticsearch-mapper-attachments/2.3.2

创建一个映射到附件插件文档的附件类

Create an Attachment Class that maps to the Attachment Plugin Documentation

  public class Attachment
  {
      [ElasticProperty(Name = "_content")]
      public string Content { get; set; }

      [ElasticProperty(Name = "_content_type")]
      public string ContentType { get; set; }

      [ElasticProperty(Name = "_name")]
      public string Name { get; set; }
  }

在要索引的 Document 类上添加一个属性，名称为File"并正确映射

Add a property on the Document class you are indexing with the name "File" and correct mapping

  [ElasticProperty(Type = FieldType.Attachment, TermVector = TermVectorOption.WithPositionsOffsets, Store = true)]
  public Attachment File { get; set; }

在索引类的任何实例之前显式创建索引.如果您不这样做，它将使用动态映射并忽略您的属性映射.如果您以后更改映射，请始终重新创建索引.

Create your index explicitly before you index any instances of your class. If you don't do this, it will use dynamic mapping and ignore your attribute mapping. If you change your mapping in the future, always recreate the index.

  client.CreateIndex("index-name", c => c
     .AddMapping<Document>(m => m.MapFromAttributes())
  );

索引您的项目

  string path = "test.pdf";

  var attachment = new Attachment();
  attachment.Content = Convert.ToBase64String(File.ReadAllBytes(path));
  attachment.ContentType = "application/pdf";
  attachment.Name = "test.pdf";

  var doc = new Document()
  {
      Id = 1,
      Title = "test",
      File = attachment
  };
  client.Index<Document>(item);

搜索文件属性

  var query = Query<Document>.Term("file", "searchTerm");

  var searchResults = client.Search<Document>(s => s
          .From(start)
          .Size(count)
          .Query(query)
  );

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