[英]Static Query Building with NEST
I'm playing around with Elasticsearch and NEST. 我正在玩Elasticsearch和NEST。
I do have some trouble understanding the various classes and interfaces which can be used to create and build static queries. 我在理解可用于创建和构建静态查询的各种类和接口时遇到一些麻烦。
Here's a simplified example of what I want to achieve: 这是我想要实现的简化示例:
using Nest;
using System;
using System.Text;
namespace NestTest
{
public class Product
{
public string Name { get; set; }
public int Price { get; set; }
}
public class ProductFilter
{
public string[] IncludeNames { get; set; }
public string[] ExcludeNames { get; set; }
public int MaxPrice { get; set; }
}
class Program
{
static void Main(string[] args)
{
var filter = new ProductFilter();
filter.MaxPrice = 100;
filter.IncludeNames = new[] { "Notebook", "Workstation" };
filter.ExcludeNames = new[] { "Router", "Modem" };
var query = CreateQueryFromFilter(filter);
var client = new ElasticClient();
// Test Serialization
var serialized = Encoding.UTF8.GetString(client.Serializer.Serialize(query));
Console.WriteLine(serialized);
// TODO: How to convert the IQuery to QueryContainer?
//client.Search<Product>(s => s.Query(q => query));
}
private static IQuery CreateQueryFromFilter(ProductFilter filter)
{
var baseBoolean = new BoolQueryDescriptor<Product>();
if (filter.IncludeNames != null && filter.IncludeNames.Length > 0)
{
foreach (var include in filter.IncludeNames)
{
// TODO: This overwrites the previous must
baseBoolean.Must(q => q.Term(t => t.Name, include));
}
}
if (filter.ExcludeNames != null && filter.ExcludeNames.Length > 0)
{
foreach (var exclude in filter.ExcludeNames)
{
// TODO: This overwrites the previous must
baseBoolean.MustNot(q => q.Term(t => t.Name, exclude));
}
}
if (filter.MaxPrice > 0)
{
// TODO: This overwrites the previous must
baseBoolean.Must(q => q.Range(r => r.LowerOrEquals(filter.MaxPrice).OnField(f => f.Price)));
}
return baseBoolean;
}
}
}
As you can see, I'd like to create some kind of query object (most likely BoolQuery) and then fill this object later on. 如您所见,我想创建某种查询对象(很可能是BoolQuery),然后再填充此对象。 I've added some TODOS in code where I have the actual problems. 我在代码中添加了一些TODOS,我遇到了实际问题。 But in general, there are just too many possibilities (IQuery, QueryContainer, XXXQueryDescriptor, SearchDescriptor, SearchRequest) and I cannot figure out how to successfully "build" a query part by part. 但总的来说,有太多的可能性(IQuery,QueryContainer,XXXQueryDescriptor,SearchDescriptor,SearchRequest),我无法弄清楚如何逐个成功地“构建”查询。
Anybody who could enlighten me? 谁能开导我?
Combinding boolean queries is described in the documentation here: 这里的文档描述了组合布尔查询:
http://nest.azurewebsites.net/nest/writing-queries.html http://nest.azurewebsites.net/nest/writing-queries.html
That page is slightly outdated and will be updated soon although most of it still applies I updated your CreateQueryFromFilter
method to showcase the several ways you can formulate queries: 该页面稍微过时,即将更新,但大部分内容仍然适用我更新了您的CreateQueryFromFilter
方法,以展示您可以制定查询的几种方法:
private static IQueryContainer CreateQueryFromFilter(ProductFilter filter)
{
QueryContainer queryContainer = null;
if (filter.IncludeNames != null && filter.IncludeNames.Length > 0)
{
foreach (var include in filter.IncludeNames)
{
//using object initializer syntax
queryContainer &= new TermQuery()
{
Field = Property.Path<Product>(p => p.Name),
Value = include
};
}
}
if (filter.ExcludeNames != null && filter.ExcludeNames.Length > 0)
{
foreach (var exclude in filter.ExcludeNames)
{
//using static Query<T> to dispatch fluent syntax
//note the ! support here to introduce a must_not clause
queryContainer &= !Query<Product>.Term(p => p.Name, exclude);
}
}
if (filter.MaxPrice > 0)
{
//fluent syntax through manually newing a descriptor
queryContainer &= new QueryDescriptor<Product>()
.Range(r => r.LowerOrEquals(filter.MaxPrice).OnField(f => f.Price)
);
}
return queryContainer;
}
Here's how you can pass that to a search operation: 以下是将其传递给搜索操作的方法:
static void Main(string[] args)
{
//using the object initializer syntax
client.Search<Product>(new SearchRequest()
{
Query = query
});
//using fluent syntax
client.Search<Product>(s => s.Query(query));
}
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