c# - ElasticSearch 索引适用于 REST API,但不适用于 C# 代码
问题描述
我正在尝试索引包含弹性搜索中的地理点的数据。当我通过代码索引时,它失败了。当我通过 REST 端点建立索引时,它成功了。但是我找不到通过 REST 端点发送的 JSON 和使用代码时发送的 JSON 之间的区别。
这是配置索引的代码(作为 LINQPad 程序):
async Task Main()
{
var pool = new SingleNodeConnectionPool(new Uri("http://localhost:9200"));
var connectionSettings = new ConnectionSettings(pool)
.DefaultMappingFor<DataEntity>(m => m.IndexName("data").TypeName("_doc"));
var client = new ElasticClient(connectionSettings);
await client.CreateIndexAsync(
"data",
index => index.Mappings(mappings => mappings.Map<DataEntity>(mapping => mapping.AutoMap().Properties(
properties => properties.GeoPoint(field => field.Name(x => x.Location))))));
// var data = new DataEntity(new GeoLocationEntity(50, 30));
//
// var json = client.RequestResponseSerializer.SerializeToString(data);
// json.Dump("JSON");
//
// var indexResult = await client.IndexDocumentAsync(data);
// indexResult.DebugInformation.Dump("Debug Information");
}
public sealed class GeoLocationEntity
{
[JsonConstructor]
public GeoLocationEntity(
double latitude,
double longitude)
{
this.Latitude = latitude;
this.Longitude = longitude;
}
[JsonProperty("lat")]
public double Latitude { get; }
[JsonProperty("lon")]
public double Longitude { get; }
}
public sealed class DataEntity
{
[JsonConstructor]
public DataEntity(
GeoLocationEntity location)
{
this.Location = location;
}
[JsonProperty("location")]
public GeoLocationEntity Location { get; }
}
运行此之后,我的映射看起来正确,因为GET /data/_doc/_mapping
返回:
{
"data" : {
"mappings" : {
"_doc" : {
"properties" : {
"location" : {
"type" : "geo_point"
}
}
}
}
}
}
我可以通过开发控制台成功地将文档添加到索引中:
POST /data/_doc
{
"location": {
"lat": 88.59,
"lon": -98.87
}
}
结果是:
{
"_index" : "data",
"_type" : "_doc",
"_id" : "RqpyjGgBZ27KOduFRIxL",
"_version" : 1,
"result" : "created",
"_shards" : {
"total" : 2,
"successful" : 1,
"failed" : 0
},
"_seq_no" : 0,
"_primary_term" : 1
}
但是当我取消注释上面的 LINQPad 程序中的代码并执行时,索引时出现此错误:
Invalid NEST response built from a unsuccessful low level call on POST: /data/_doc
# Audit trail of this API call:
- [1] BadResponse: Node: http://localhost:9200/ Took: 00:00:00.0159927
# OriginalException: Elasticsearch.Net.ElasticsearchClientException: The remote server returned an error: (400) Bad Request.. Call: Status code 400 from: POST /data/_doc. ServerError: Type: mapper_parsing_exception Reason: "failed to parse" CausedBy: "Type: parse_exception Reason: "field must be either [lat], [lon] or [geohash]"" ---> System.Net.WebException: The remote server returned an error: (400) Bad Request.
at System.Net.HttpWebRequest.EndGetResponse(IAsyncResult asyncResult)
at Elasticsearch.Net.HttpWebRequestConnection.<>c__DisplayClass5_0`1.<RequestAsync>b__1(IAsyncResult r)
at System.Threading.Tasks.TaskFactory`1.FromAsyncCoreLogic(IAsyncResult iar, Func`2 endFunction, Action`1 endAction, Task`1 promise, Boolean requiresSynchronization)
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task)
at Elasticsearch.Net.HttpWebRequestConnection.<RequestAsync>d__5`1.MoveNext()
--- End of inner exception stack trace ---
# Request:
<Request stream not captured or already read to completion by serializer. Set DisableDirectStreaming() on ConnectionSettings to force it to be set on the response.>
# Response:
<Response stream not captured or already read to completion by serializer. Set DisableDirectStreaming() on ConnectionSettings to force it to be set on the response.>
转储的 JSON 如下所示:
{
"location": {
"latitude": 50.0,
"longitude": 30.0
}
}
因此它与在开发控制台中工作的 JSON 的结构相匹配。
为了解决这个问题,我编写了一个自定义,以以下格式JsonConverter
序列化我的对象:GeoLocationEntity
{lat},{lon}
public sealed class GeoLocationConverter : JsonConverter
{
public override bool CanConvert(Type objectType) =>
objectType == typeof(GeoLocationEntity);
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
var token = JToken.Load(reader);
if (!(token is JValue))
{
throw new JsonSerializationException("Token was not a primitive.");
}
var stringValue = (string)token;
var split = stringValue.Split(',');
var latitude = double.Parse(split[0]);
var longitude = double.Parse(split[1]);
return new GeoLocationEntity(latitude, longitude);
}
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
var geoLocation = (GeoLocationEntity)value;
if (geoLocation == null)
{
writer.WriteNull();
return;
}
var geoLocationValue = $"{geoLocation.Latitude},{geoLocation.Longitude}";
writer.WriteValue(geoLocationValue);
}
}
将此JsonConverter
应用于序列化程序设置让我解决了这个问题。但是,我不想解决这样的问题。
谁能启发我如何解决这个问题?
解决方案
6.x Elasticsearch 高级客户端 NEST 通过以下方式内化了 Json.NET 依赖项
- IL 合并 Json.NET 程序集
- 将所有类型转换为
internal
- 将它们重命名为
Nest.*
这在实践中意味着客户端不直接依赖于 Json.NET(阅读发布博客文章以了解我们这样做的原因)并且不知道 Json.NET 类型,包括JsonPropertyAttribute
或JsonConverter
.
有几种方法可以解决这个问题。首先,以下设置在开发过程中可能会有所帮助
var defaultIndex = "default-index";
var pool = new SingleNodeConnectionPool(new Uri("http://localhost:9200"));
var settings = new ConnectionSettings(pool)
.DefaultMappingFor<DataEntity>(m => m
.IndexName(defaultIndex)
.TypeName("_doc")
)
.DisableDirectStreaming()
.PrettyJson()
.OnRequestCompleted(callDetails =>
{
if (callDetails.RequestBodyInBytes != null)
{
Console.WriteLine(
$"{callDetails.HttpMethod} {callDetails.Uri} \n" +
$"{Encoding.UTF8.GetString(callDetails.RequestBodyInBytes)}");
}
else
{
Console.WriteLine($"{callDetails.HttpMethod} {callDetails.Uri}");
}
Console.WriteLine();
if (callDetails.ResponseBodyInBytes != null)
{
Console.WriteLine($"Status: {callDetails.HttpStatusCode}\n" +
$"{Encoding.UTF8.GetString(callDetails.ResponseBodyInBytes)}\n" +
$"{new string('-', 30)}\n");
}
else
{
Console.WriteLine($"Status: {callDetails.HttpStatusCode}\n" +
$"{new string('-', 30)}\n");
}
});
var client = new ElasticClient(settings);
这会将所有请求和响应写入控制台,因此您可以看到客户端从 Elasticsearch 发送和接收的内容。.DisableDirectStreaming()
在内存中缓冲请求和响应字节,以使它们可用于传递给的委托.OnRequestCompleted()
,因此它对开发很有用,但您可能不希望它在生产中使用,因为它会降低性能。
现在,解决方案:
1.使用PropertyNameAttribute
JsonPropertyAttribute
您可以使用PropertyNameAttribute
来命名序列化的属性,而不是使用
public sealed class GeoLocationEntity
{
public GeoLocationEntity(
double latitude,
double longitude)
{
this.Latitude = latitude;
this.Longitude = longitude;
}
[PropertyName("lat")]
public double Latitude { get; }
[PropertyName("lon")]
public double Longitude { get; }
}
public sealed class DataEntity
{
public DataEntity(
GeoLocationEntity location)
{
this.Location = location;
}
[PropertyName("location")]
public GeoLocationEntity Location { get; }
}
并使用
if (client.IndexExists(defaultIndex).Exists)
client.DeleteIndex(defaultIndex);
var createIndexResponse = client.CreateIndex(defaultIndex, c => c
.Mappings(m => m
.Map<DataEntity>(mm => mm
.AutoMap()
.Properties(p => p
.GeoPoint(g => g
.Name(n => n.Location)
)
)
)
)
);
var indexResponse = client.Index(
new DataEntity(new GeoLocationEntity(88.59, -98.87)),
i => i.Refresh(Refresh.WaitFor)
);
var searchResponse = client.Search<DataEntity>(s => s
.Query(q => q
.MatchAll()
)
);
PropertyNameAttribute
行为类似于您通常JsonPropertAttribute
与 Json.NET 一起使用的方式。
2.使用DataMemberAttribute
PropertyNameAttribute
如果您不希望 POCO 与 NEST 类型相关联,这将与本例中的情况相同(尽管我认为 POCO 与 Elasticsearch 相关联,因此将它们与 .NET Elasticsearch 类型相关联可能不是问题)。
3.使用Geolocation
类型
您可以将GeoLocationEntity
type 替换为 Nest 的GeoLocation
类型,该类型映射到geo_point
字段数据类型映射。在使用这个的时候,少了一个POCO,从属性类型中可以推断出正确的映射关系
public sealed class DataEntity
{
public DataEntity(
GeoLocation location)
{
this.Location = location;
}
[DataMember(Name = "location")]
public GeoLocation Location { get; }
}
// ---
if (client.IndexExists(defaultIndex).Exists)
client.DeleteIndex(defaultIndex);
var createIndexResponse = client.CreateIndex(defaultIndex, c => c
.Mappings(m => m
.Map<DataEntity>(mm => mm
.AutoMap()
)
)
);
var indexResponse = client.Index(
new DataEntity(new GeoLocation(88.59, -98.87)),
i => i.Refresh(Refresh.WaitFor)
);
var searchResponse = client.Search<DataEntity>(s => s
.Query(q => q
.MatchAll()
)
);
4. 连接 JsonNetSerializer
NEST 允许连接自定义序列化程序,以负责序列化您的类型。一个单独的 nuget 包NEST.JsonNetSerializer允许您使用 Json.NET 序列化您的类型,序列化程序委托回内部序列化程序以获取 NEST 类型的属性。
首先,您需要将 JsonNetSerializer 传递给ConnectionSettings
构造函数
var settings = new ConnectionSettings(pool, JsonNetSerializer.Default)
然后您的原始代码将按预期工作,无需自定义JsonConverter
public sealed class GeoLocationEntity
{
public GeoLocationEntity(
double latitude,
double longitude)
{
this.Latitude = latitude;
this.Longitude = longitude;
}
[JsonProperty("lat")]
public double Latitude { get; }
[JsonProperty("lon")]
public double Longitude { get; }
}
public sealed class DataEntity
{
public DataEntity(
GeoLocationEntity location)
{
this.Location = location;
}
[JsonProperty("location")]
public GeoLocationEntity Location { get; }
}
// ---
if (client.IndexExists(defaultIndex).Exists)
client.DeleteIndex(defaultIndex);
var createIndexResponse = client.CreateIndex(defaultIndex, c => c
.Mappings(m => m
.Map<DataEntity>(mm => mm
.AutoMap()
.Properties(p => p
.GeoPoint(g => g
.Name(n => n.Location)
)
)
)
)
);
var indexResponse = client.Index(
new DataEntity(new GeoLocationEntity(88.59, -98.87)),
i => i.Refresh(Refresh.WaitFor)
);
var searchResponse = client.Search<DataEntity>(s => s
.Query(q => q
.MatchAll()
)
);
我最后列出了这个选项,因为在内部,以这种方式将序列化传递给 Json.NET 会产生性能和分配开销。包含它是为了提供灵活性,但我建议仅在您真正需要时才使用它,例如,在序列化结构不常规的情况下完成 POCO 的自定义序列化。我们正在致力于更快的序列化,这将在未来减少这种开销。
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