Elasticsearch 入門（三）使用Elasticsearch.Net & NEST作為elasticsearch客戶端

GitHub倉庫

• https://github.com/elastic/elasticsearch-net
• 選擇 Elasticsearch.Net 作為客戶端
• 連接方式

var node = new Uri("http://myserver:9200");
var config = new ConnectionConfiguration(node);
var client = new ElasticLowLevelClient(config);

var myJson = @"{ ""hello"" : ""world"" }";
client.Index<StringResponse>("myindex", "1", myJson);
var myJson = new { hello = "world" };
client.Index<BytesResponse>("myindex", "1", PostData.Serializable(myJson));

Elasticsearch.Net 封裝

• 新建 ElasticSearchClient類

    public class ElasticSearchClient
    {
        public ElasticLowLevelClient Client { get; }

        private readonly IConfiguration _configuration;

        public ElasticSearchClient(IConfiguration configuration)
        {
            _configuration = configuration;
            Client = InitClient();
        }

        #region Methods
        public async Task<string> Index(string index, string id, PostData body)
        {
            var response = await Client.IndexAsync<StringResponse>(index, id, body);

            ResponseValidate(response);
            return response.Body;
        }

        public async Task<List<string>> SearchWithHighLight(string index, string query)
        {
            var response = await Client.SearchAsync<StringResponse>(
                index,
                PostData.Serializable(new
                {
                    from = 0,
                    size = 100,
                    query = new
                    {
                        match = new
                        {
                            content = query
                        }
                    },
                    highlight = new
                    {
                        pre_tags = new[] { "<tag1>", "<tag2>" },
                        post_tags = new[] { "/<tag1>", "/<tag2>" },
                        fields = new
                        {
                            content = new { }
                        }
                    }
                }));

            ResponseValidate(response);
            var responseJson = (JObject)JsonConvert.DeserializeObject(response.Body);

            var hits = responseJson["hits"]["hits"] as JArray;

            var result = new List<string>();

            foreach (var hit in hits)
            {
                var id = hit["_id"].ToObject<string>();

                result.Add(id);
            }

            return result;
        }

        public async Task Delete(string index, string id)
        {
            var response = await Client.DeleteAsync<StringResponse>(index, id);

            ResponseValidate(response);
        }
        #endregion

        #region privates
        private ElasticLowLevelClient InitClient()
        {
            var node = new Uri(_configuration.GetConnectionString("ElasticSearch"));
            var settings = new ConnectionConfiguration(node);
            var client = new ElasticLowLevelClient(settings);

            return client;
        }

        private void ResponseValidate(StringResponse response)
        {
            if (response.Success == false)
            {
                throw new ResultException(response.Body);
            }
        }

        #endregion

    }

• 依賴註入 Startup.csservices.AddScoped<ElasticSearchClient>();
• 使用

private readonly ElasticSearchClient _elasticSearchClient;
await _elasticSearchClient.Index(Article.EsIndex, article.ArticleUID,PostData.Serializable(article));