Question

我有以下DocumentDB存储库帮助程序类

using Microsoft.Azure.Documents;
using Microsoft.Azure.Documents.Client;
using Microsoft.Azure.Documents.Linq;
using System;
using System.Collections.Generic;
using System.Configuration;
using System.Linq;
using System.Linq.Expressions;
using System.Threading.Tasks;
using System.Web;

namespace TenantManagementWebApi.DataAccess
{
    public static class DocumentDBRepository<T> where T : class
    {
        private static readonly string DatabaseId = ConfigurationManager.AppSettings["database"];
        private static readonly string CollectionId = ConfigurationManager.AppSettings["collection"];
        private static DocumentClient client;

        public static async Task<T> GetItemAsync(string id)
        {
            try
            {
                Document document = await client.ReadDocumentAsync(UriFactory.CreateDocumentUri(DatabaseId, CollectionId, id));
                return (T)(dynamic)document;
            }
            catch (DocumentClientException e)
            {
                if (e.StatusCode == System.Net.HttpStatusCode.NotFound)
                {
                    return null;
                }
                else
                {
                    throw;
                }
            }
        }

        public static async Task<IEnumerable<T>> GetItemsAsync(Expression<Func<T, bool>> predicate)
        {
            IDocumentQuery<T> query = client.CreateDocumentQuery<T>(
                UriFactory.CreateDocumentCollectionUri(DatabaseId, CollectionId),
                new FeedOptions { MaxItemCount = -1 })
                .Where(predicate)
                .AsDocumentQuery();

            List<T> results = new List<T>();
            while (query.HasMoreResults)
            {
                results.AddRange(await query.ExecuteNextAsync<T>());
            }

            return results;
        }

        public static async Task<Document> CreateItemAsync(T item)
        {
            return await client.CreateDocumentAsync(UriFactory.CreateDocumentCollectionUri(DatabaseId, CollectionId), item);
        }

        public static async Task<Document> UpdateItemAsync(string id, T item)
        {
            return await client.ReplaceDocumentAsync(UriFactory.CreateDocumentUri(DatabaseId, CollectionId, id), item);
        }

        public static async Task DeleteItemAsync(string id)
        {
            await client.DeleteDocumentAsync(UriFactory.CreateDocumentUri(DatabaseId, CollectionId, id));
        }

        public static void Initialize()
        {
            client = new DocumentClient(new Uri(ConfigurationManager.AppSettings["endpoint"]), ConfigurationManager.AppSettings["authKey"]);
            CreateDatabaseIfNotExistsAsync().Wait();
            CreateCollectionIfNotExistsAsync().Wait();
        }

        private static async Task CreateDatabaseIfNotExistsAsync()
        {
            try
            {
                await client.ReadDatabaseAsync(UriFactory.CreateDatabaseUri(DatabaseId));
            }
            catch (DocumentClientException e)
            {
                if (e.StatusCode == System.Net.HttpStatusCode.NotFound)
                {
                    await client.CreateDatabaseAsync(new Database { Id = DatabaseId });
                }
                else
                {
                    throw;
                }
            }
        }

        private static async Task CreateCollectionIfNotExistsAsync()
        {
            try
            {
                await client.ReadDocumentCollectionAsync(UriFactory.CreateDocumentCollectionUri(DatabaseId, CollectionId));
            }
            catch (DocumentClientException e)
            {
                if (e.StatusCode == System.Net.HttpStatusCode.NotFound)
                {
                    await client.CreateDocumentCollectionAsync(
                        UriFactory.CreateDatabaseUri(DatabaseId),
                        new DocumentCollection { Id = CollectionId },
                        new RequestOptions { OfferThroughput = 1000 });
                }
                else
                {
                    throw;
                }
            }
        }
    }
}

我需要为一个实体做webapi crud控制器：

 public class Tenant
    {
        public string TenantId { get; set; }
        public string TenantUrl { get; set; }
        public string CertificatePath { get; set; }
        public string CertificatePassword { get; set; }

        public override string ToString()
        {
            return JsonConvert.SerializeObject(this);
        }
    }

我不确定要在谓词中添加什么来获取所有属于租户的项目。

 public async Task<List<Tenant>> GetTenants()
        {
            return await  DocumentDBRepository<List<Tenant>>.GetItemsAsync(d => d. != null);
        }

Answer 1

您需要使通用T对象更加具体。将其限制为实现诸如ICosmosEntity之类的接口的类，并在该接口上添加EntityType属性。

然后使您的DTO实现该接口，并将EntityType设置为类名。这样，您就可以创建一个动态谓词，该谓词获取nameof(T)并自动将其添加到LINQ查询的Where子句中。

如果您只想获取集合中的所有项目，那么在您的代码中，x => true谓词可以做到这一点，但是除非集合中仅包含租户对象，否则它不会将它限制在租户中。

ReadDocumentAsync仅在您的集合没有分区键时才值得这样做（不建议这样做）

也许值得一看Cosmonaut，因为它确实可以满足您的需求以及更多。它支持与您尝试编写的代码完全相同的collection sharing逻辑。

免责声明，我是宇航员的创造者。

如何通过webapi从DocumentDB中正确获取所有项目

1 个答案: