.net – 使用LINQ处理弹性搜索结果

使用LINQ处理ElasticSearch结果的最有效方法是什么？

我遇到了JSON.Net的JObject Class.

从ElasticSearch返回的JSON是否通过JObject类以适合LINQ查询的方式构建？

这是关于如何利用LINQ处理来自elasticsearch引擎的JSON查询结果的完整解决方案.

连接库 – PlainElastic.NET

首先,我将PlainElastic.NET用于一个目的：连接到我的elasticsearch服务器.该库非常精简,包含简洁的GET,POST和PUT功能.这将在下面与客户端连接对象发挥作用. result.ToString()提供来自elasticsearch服务器的JSON响应.只需将DLL打入您的bin并添加引用即可.

JSON处理器 – JSON.NET

我正在使用NewtonSoft JSON.NET的一个很棒的功能来促进LINQ查询.该库有一个JObject类,它提供了一个可嵌套的可查询结构来执行LINQ.请参阅下面的行,我抓住HitCount以查看获取单个值有多好,当然,请查看LINQ查询以查看如何查询它.请记住,这只是一个数据结构,它是解析JSON字符串的结果.只需将DLL打入您的bin并添加引用即可.

执行针对弹性搜索的查询

'Execute the Search
Dim client = New ElasticConnection("localhost", 9200)
Dim result = client.Post("myindex/mytype/_search", elastic_query) 'elastic_query = well-formatted elasticsearch query (json string)'
Dim J As JObject = JObject.Parse(result.ToString())

'How many results were located? 
Dim HitCount = CInt(J("hits")("total"))

'What was the maximum score? Maybe you want to know this for normalizing scores to 0-100.
' - We make sure we have hits first
' - Also, make sure scoring is turned on. It might be turned off if an alternate sort method is used in your query
If HitCount > 0 AndAlso J("hits")("max_score").Type <> JTokenType.Null Then MaxScore = CDbl(J("hits")("max_score"))

使用LINQ处理结果

现在,使用LINQ提供一个漂亮的匿名对象来绑定到Gridviews,DataLists,Repeater等.我有意提供了一个非平凡的LINQ查询示例.此示例获取嵌套数据(商店,类别)

Dim SearchResults = _
  (From X In J("hits")("hits")
    Select
      score = CDec(If(X("_score").Type = JTokenType.Null, 0, X("_score"))),
      boost = CDbl(X("_source")("_boost")),
      InstitutionID = CInt(X("_source")("InstitutionID")),
      Name = CStr(X("_source")("Name")),
      Stores = (From S In X("_source")("Stores") Select CInt(S("StoreID"))).ToList(),
      Categories = (From Z In X("_source")("Categories") Select CatID = CInt(Z("CatID")), CatName = CStr(Z("CatName")), InstitutionID = CInt(X("_source")("InstitutionID"))).ToList()
 Order By score Descending, boost Descending
)

现在,您可以绑定到Repeater,DataList或Gridview

MyRepeater.DataSource = SearchResults
MyRepeater.DataBind()