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CRUD .NET Core e DynamoDB

CRUD .NET Core e DynamoDB

Bom pessoal, estou de volta com a série de artigos .NET Core e AWS. No artigo de hoje faremos acesso ao banco noSQL DynamoDB da AWS.

Apesar de ser iniciante em .Net (e ainda cometer erros), já sei o suficiente para compartilhar o que estou aprendendo com vocês. 🙂

Caso queira ler o artigo anterior, acesse o link abaixo:

https://www.profissionaloracle.com.br/2019/11/10/criando-um-serverless-net-core-web-api-com-aws-lambda/

DynamoDB

Não vou entrar em detalhes sobre o DynamoDB, mas se você quiser mais informações sobre ele, acesse esse link.

Se isso não for suficiente, a edX está oferecendo um curso totalmente gratuito de DynamoDB. Acesse o post abaixo e veja como se inscrever.

https://www.profissionaloracle.com.br/2019/06/12/amazon-dynamodb-building-nosql-database-driven-applications-curso-gratuito/

Também existe um guia muito bom que você pode utilizar:

https://www.profissionaloracle.com.br/2019/06/07/guia-de-aprendizado-dynamodb/

Se você estudar qualquer um dos materiais citados, já estará apto para acompanhar este artigo ! 🙂

Vamos agora continuar e criar o nosso banco DynamoDB na AWS.

Acesse sua conta da AWS, clique em Serviços e procure por DynamoDB.

image 16

Clique em Create Table.

Chamaremos a nossa tabela de ProductList.

Clique no botão Criar.

image 3

Faça a inserção dos dados no DynamoDb.

image 4

Agora já temos o suficiente para testar. Abra o Visual Studio e vamos iniciar o nosso projeto.

Clique em Create a new project e escolha o template ASP.Net Core Web Application.

image 26

Vamos chamar o nosso projeto de AWSProductListDynamoDb.

image 27

Agora escolha Empty, pois vamos escrever na mão as classes. Clique em Create para criar o nosso projeto.

image 28

Vamos instalar o pacote com o SDK da AWS. Para isso, acesse o Package Manager Console em View >> Other Windows >> Package Manager Console.

image 29

Digite no Package Manager Console: install-package AWSSDK.Extensions.NETCore.Setup

image 30

Verifique se a instalação ocorreu sem erros.

image 31

Agora iremos instalar o nuget do DynamoDB. Para isso, digite install-package AWSSDK.DynamoDBv2.

image 32

Verifique se a instalação ocorreu sem erros:

image 33

Agora vamos começar a implementar as classes que farão todas as operações básicas com o banco de dados:

  • Criação da tabela
  • Inserção de dados
  • Leitura de dados
  • Exclusão de dados

Primeiramente, vamos criar o nosso arquivo appsettings.json que conterá as informações necessárias para conexão com o DynamoDB na AWS e também alguns parâmetros referentes a tabela. Os principais para são:

  • Region
  • AccessKey
  • SecretKey
{
   "AWS": {
     "Region": "sa-east-1",
     "AccessKey": "XXXXXXXXXXXXXXXXXXX",
     "SecretKey": "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"
   },
   "VAR": {
      "TableName":  "ProductList"
   }
 }

Dica: Para descobrir o Region onde o seu serviço está executando, no painel da AWS, clique na região e a nomenclatura aparecerá:

image 14

Agora vamos ao IAM (Identity Access Management) para criar o nosso usuário de acesso ao DynamoDB e assim gerar o AccessKey e o SecretKey. Para isso acesse USUÁRIOS e clique no botão adicionar usuário.

image 15

Vamos dar o nome de nosso usuário de test_dyn, e o tipo de acesso será o programático.

image 16

Para simplificar, vamos anexar as políticas de forma direta, como na imagem a seguir. A política de permissão que daremos ao nosso usuário é a AmazonDynamoDBFullAccess. Como o objetivo desse artigo não é a criação de grupos e usuários, faremos do jeito mais simples.

image 17

Vamos pular a parte de tags e ir direto a Revisão. Verifique se está tudo Ok e clique em Criar usuário.

image 18

Pronto, agora obtemos o AccessKey e o SecretKey para acessarmos o nosso banco de dados.

image 19

Agora que já temos o nosso usuário de acesso, e as chaves, vamos voltar ao nosso projeto.

Crie um novo Projeto do tipo Class Library (.NET Core) chamado AWSProductListDynamoDb. Aqui ficará todas as interfaces e classes responsáveis pelo CRUD.

Clique com o botão direito e depois em Add Reference. Selecione AWSProductListDynamoDb.Libs e clique em OK. Assim o nosso projeto principal terá acesso a todas as classes de nossa Lib.

image 22
image 21

Agora, vamos instalar o pacote do DynamoDB no segundo projeto.

image 20
PM> install-package AWSSDK.DynamoDBv2
 Restoring packages for C:\Users\gioth\source\repos\AWSProductListDynamoDB\AWSProductListDynamoDB.Libs\AWSProductListDynamoDb.Libs.csproj…
   GET https://api.nuget.org/v3-flatcontainer/awssdk.dynamodbv2/index.json
   OK https://api.nuget.org/v3-flatcontainer/awssdk.dynamodbv2/index.json 576ms
   GET https://api.nuget.org/v3-flatcontainer/awssdk.dynamodbv2/3.3.104.2/awssdk.dynamodbv2.3.3.104.2.nupkg
   OK https://api.nuget.org/v3-flatcontainer/awssdk.dynamodbv2/3.3.104.2/awssdk.dynamodbv2.3.3.104.2.nupkg 14ms
   GET https://api.nuget.org/v3-flatcontainer/awssdk.core/index.json
   OK https://api.nuget.org/v3-flatcontainer/awssdk.core/index.json 566ms
   GET https://api.nuget.org/v3-flatcontainer/awssdk.core/3.3.104/awssdk.core.3.3.104.nupkg
   OK https://api.nuget.org/v3-flatcontainer/awssdk.core/3.3.104/awssdk.core.3.3.104.nupkg 10ms
 Installing AWSSDK.Core 3.3.104.
 Installing AWSSDK.DynamoDBv2 3.3.104.2.
 Installing NuGet package AWSSDK.DynamoDBv2 3.3.104.2.
 Committing restore…
 Generating MSBuild file C:\Users\gioth\source\repos\AWSProductListDynamoDB\AWSProductListDynamoDB.Libs\obj\AWSProductListDynamoDb.Libs.csproj.nuget.g.props.
 Writing assets file to disk. Path: C:\Users\gioth\source\repos\AWSProductListDynamoDB\AWSProductListDynamoDB.Libs\obj\project.assets.json
 Restore completed in 3,36 sec for C:\Users\gioth\source\repos\AWSProductListDynamoDB\AWSProductListDynamoDB.Libs\AWSProductListDynamoDb.Libs.csproj.
 Successfully installed 'AWSSDK.Core 3.3.104' to AWSProductListDynamoDb.Libs
 Successfully installed 'AWSSDK.DynamoDBv2 3.3.104.2' to AWSProductListDynamoDb.Libs
 Committing restore…
 Assets file has not changed. Skipping assets file writing. Path: C:\Users\gioth\source\repos\AWSProductListDynamoDB\AWSProductListDynamoDB\obj\project.assets.json
 Restore completed in 19,77 ms for C:\Users\gioth\source\repos\AWSProductListDynamoDB\AWSProductListDynamoDB\AWSProductListDynamoDb.csproj.
 NuGet Config files used:
     C:\Users\gioth\AppData\Roaming\NuGet\NuGet.Config
     C:\Program Files (x86)\NuGet\Config\Microsoft.VisualStudio.Offline.config
     C:\Program Files (x86)\NuGet\Config\Xamarin.Offline.config
 Feeds used:
     https://api.nuget.org/v3/index.json
     C:\Program Files (x86)\Microsoft SDKs\NuGetPackages\
 Executing nuget actions took 357,9 ms
 Time Elapsed: 00:00:05.5700886
 PM> 

Nosso ambiente agora está pronto ! Vamos começar a implementar o nosso CRUD.

No projeto .Net Core teremos:

image 1

AWSProductListDynamoDBStartup.cs

using System;
using System.IO;
using Amazon.DynamoDBv2;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Configuration;
using AWSProductListDynamoDb.Libs.AWSProductListDynamoDb;

namespace AWSProductListDynamoDb
{
    public class Startup
    {
        public Startup()
        {
            Configuration = new ConfigurationBuilder()
                .SetBasePath(Directory.GetCurrentDirectory())
                .AddJsonFile("appsettings.json")
                .Build();
        }

        public IConfigurationRoot Configuration { get; set; } 
        
        // This method gets called by the runtime. Use this method to add services to the container.
        // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddMvcCore();

            services.AddDefaultAWSOptions(Configuration.GetAWSOptions());

            Environment.SetEnvironmentVariable("AWS_ACCESS_KEY_ID",Configuration["AWS:AccessKey"]);
            Environment.SetEnvironmentVariable("AWS_SECRET_ACCESS_KEY",Configuration["AWS:SecretKey"]);
            Environment.SetEnvironmentVariable("AWS_REGION", Configuration["AWS:Region"]);
            Environment.SetEnvironmentVariable("AWS_CONTENT", Configuration["VAR:TableName"]);

            services.AddAWSService<IAmazonDynamoDB>();

            services.AddSingleton<IAWSProductListDynamoDbExamples, AWSProductListDynamoDbExamples>();
            services.AddSingleton<IInsertItem, InsertItem>();
            services.AddSingleton<IQueryItem, QueryItem>();
            services.AddSingleton<IDeleteItem, DeleteItem>();

        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.UseRouting();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllerRoute("default", "{controller=Home}/{action=Index}");
            });

        }
    }
} 

AWSProductListDynamoDBProgram.cs

using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Hosting;

namespace AWSProductListDynamoDb
{
    public class Program
    {
        public static void Main(string[] args)
        {
            CreateHostBuilder(args).Build().Run();
        }

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.UseStartup<Startup>();
                });
    }
} 

AWSProductListDynamoDB – Controllers AWSProductListDynamoDb.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using AWSProductListDynamoDb.Libs.AWSProductListDynamoDb;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;

namespace AWSProductListDynamoDb.Controllers
{
    [Produces("application/json")]
    [Route("api/[controller]")]

    public class AWSProductListDynamoDBController : Controller //Base
    {
        private readonly IAWSProductListDynamoDbExamples _dynamoDbExamples;
        private readonly IInsertItem _insertItem;
        private readonly IQueryItem _queryItem;
        private readonly IDeleteItem _deleteItem;

        public AWSProductListDynamoDBController(IAWSProductListDynamoDbExamples dynamoDbExamples, IInsertItem insertItem, IQueryItem queryItem, IDeleteItem deleteItem)
        {
            _dynamoDbExamples = dynamoDbExamples;
            _insertItem = insertItem;
            _queryItem = queryItem;
            _deleteItem = deleteItem;
        }

        [Route("createtable")]
        public IActionResult CreateDynamoDbTable()
        {
            _dynamoDbExamples.CreateDynamoDbTable();

            return Ok();
        }

        [HttpPost]
        [Route("insertitem")]
        public IActionResult InsertItem([FromQuery] string productName, int productQuantity)
        {
            _insertItem.AddNewEntry(productName, productQuantity);

            return Ok();
        }
        [HttpGet]
        [Route("queryitems")]
        public async Task<IActionResult> GetItems([FromQuery] string productName)
        {
            var response = await _queryItem.GetItems(productName);

            return Ok(response);
        }
        [HttpDelete]
        [Route("deleteitems")]
        public IActionResult DeleteItems([FromQuery] string productName)
        {
            _deleteItem.DeleteEntry(productName);

            return Ok();
        }
    }
} 

O projeto Lib teremos:

image 2

AWSProductListDynamoDB.Libs – AWSProductListDynamoDB IAWSProductListDynamoDbExamples.cs (Interface)

namespace AWSProductListDynamoDb.Libs.AWSProductListDynamoDb
 {
     public interface IAWSProductListDynamoDbExamples
     {
         void CreateDynamoDbTable();
 }
 }

AWSProductListDynamoDB.Libs – AWSProductListDynamoDBAWSProductListDynamoDbExamples.cs (Classe responsável pela criação da tabela no DynamoDb)

Caso a tabela não exista, ela será criada no DynamoDB.

using Amazon.DynamoDBv2;
using Amazon.DynamoDBv2.Model;
using System;
using System.Collections.Generic;
using System.Threading;

namespace AWSProductListDynamoDb.Libs.AWSProductListDynamoDb
{
    public class AWSProductListDynamoDbExamples : IAWSProductListDynamoDbExamples
    {
        private readonly IAmazonDynamoDB _dynamoDbClient;
        private static readonly string tableName = Environment.GetEnvironmentVariable("AWS_CONTENT");

        public AWSProductListDynamoDbExamples(IAmazonDynamoDB dynamoDbClient)
        {
            _dynamoDbClient = dynamoDbClient;
        }

        public void CreateDynamoDbTable()
        {
            try
            {
                CreateTempTable();
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
                throw;
            }
        }

        private async void CreateTempTable()
        {
            Console.WriteLine("Criando a tabela...");

            var request = new CreateTableRequest
            {
                AttributeDefinitions = new List<AttributeDefinition>
                {
                    new AttributeDefinition
                    {
                        AttributeName = "ProductName",
                        AttributeType = ScalarAttributeType.S //String
                    },
                    new AttributeDefinition
                    {
                        AttributeName = "ProductQuantity",
                        AttributeType = ScalarAttributeType.N //Number
                    }

                },
                KeySchema = new List<KeySchemaElement>
                {
                    new KeySchemaElement
                    {
                        AttributeName = "ProductName",
                        KeyType = "HASH"

                    },
                    new KeySchemaElement
                    {
                        AttributeName = "ProductQuantity",
                        KeyType = "RANGE"

                    }
                },
                ProvisionedThroughput = new ProvisionedThroughput
                {
                    ReadCapacityUnits = 5,
                    WriteCapacityUnits = 5
                },
                TableName = tableName
            };

            await _dynamoDbClient.CreateTableAsync(request);

            WaitUntilTableReady(tableName);
        }

        public void WaitUntilTableReady(string tableName)
        {
            string status = null;   

            do
            {
                Thread.Sleep(5000);

                try
                {
                    var res = _dynamoDbClient.DescribeTableAsync(tableName);

                    status = res.Result.Table.TableStatus;
                }

                catch (ResourceNotFoundException)
                {
                    Console.WriteLine(status);
                }

            } while (status != "ACTIVE");
            {
                Console.WriteLine("Tabela criada com sucesso !!!");          
            }
        }
    }

} 

AWSProductListDynamoDB.Libs – AWSProductListDynamoDB – Models – DynamoDbTableItems.cs

 using System;
 using System.Collections.Generic;
 using System.Text;
 namespace AWSProductListDynamoDb.Libs.Models
 {
   public class DynamoDbTableItems
   {
     public IEnumerable Items { get; set; }
   }
 }

AWSProductListDynamoDB.Libs – AWSProductListDynamoDB – Models – Item.cs

 using System;
 using System.Collections.Generic;
 using System.Text;
 namespace AWSProductListDynamoDb.Libs.Models
 {
     public class Item
     {
         public string productName { get; set; }
         public int productQuantity { get; set; }
     }
 }

AWSProductListDynamoDB.Libs – AWSProductListDynamoDB IInsertItem.cs (Interface)

 using System.Threading.Tasks;
 namespace AWSProductListDynamoDb.Libs.AWSProductListDynamoDb
 {
     public interface IInsertItem
     {
         Task AddNewEntry(string productName, int productQuantity);
     }
 }

AWSProductListDynamoDB.Libs – AWSProductListDynamoDB InsertItem.cs (Insere os dados no banco de dados)

using Amazon.DynamoDBv2;
using Amazon.DynamoDBv2.Model;
using System;
using System.Collections.Generic;
using System.Threading.Tasks;

namespace AWSProductListDynamoDb.Libs.AWSProductListDynamoDb
{
    public class InsertItem : IInsertItem
    {
        private static readonly string tableName = Environment.GetEnvironmentVariable("AWS_CONTENT");

        private readonly IAmazonDynamoDB _dynamoDbClient;
        public InsertItem(IAmazonDynamoDB dynamoDbClient)
        {
            _dynamoDbClient = dynamoDbClient;
        }
        public async Task AddNewEntry(string productName, int productQuantity)
        {
            try
            {
                var queryRequest = RequestBuilder(productName, productQuantity);

                await PutItemAsync(queryRequest);
            }
            catch (InternalServerErrorException)
            {
                Console.WriteLine("Erro 1");
            }
            catch (ResourceNotFoundException)
            {
                Console.WriteLine("Erro 2");
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.InnerException.StackTrace.ToString());
            }

        }

        private PutItemRequest RequestBuilder(string productName, int productQuantity)
        {
            Dictionary<string, AttributeValue> attributes = new Dictionary<string, AttributeValue>();

            attributes["ProductName"] = new AttributeValue { S = productName.ToString() };
            attributes["ProductQuantity"] = new AttributeValue { N = productQuantity.ToString() };

            return new PutItemRequest
            {
                TableName = tableName,
                Item = attributes
            };
        }
        private async Task PutItemAsync(PutItemRequest request)
        {
            try
            {
                await _dynamoDbClient.PutItemAsync(request);
            }
            catch (Exception ex)
            {
                Console.WriteLine("Erro: " + ex.InnerException.StackTrace.ToString());
            }
        }
    }
} 

AWSProductListDynamoDB.Libs – AWSProductListDynamoDB IQueryItem.cs (IInterface)

 using System.Threading.Tasks;
 using AWSProductListDynamoDb.Libs.Models;
 namespace AWSProductListDynamoDb.Libs.AWSProductListDynamoDb
 {
     public interface IQueryItem
     {
         Task GetItems(string? productName);
     }
 }

AWSProductListDynamoDB.Libs – AWSProductListDynamoDB QueryItem.cs (Busca os dados no banco de dados)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Amazon.DynamoDBv2;
using Amazon.DynamoDBv2.Model;
using AWSProductListDynamoDb.Libs.Models;

namespace AWSProductListDynamoDb.Libs.AWSProductListDynamoDb
{
    public class QueryItem : IQueryItem
    {
        private readonly IAmazonDynamoDB _dynamoDbClient;
        private static readonly string tableName = Environment.GetEnvironmentVariable("AWS_CONTENT");

        public QueryItem(IAmazonDynamoDB dynamoDbClient)
        {
            _dynamoDbClient = dynamoDbClient;
        }

        public async Task<DynamoDbTableItems> GetItems(string productName)
        {
            var queryRequest = RequestBuilder(productName);

            var result = await ScanAsync(queryRequest);

            return new DynamoDbTableItems
            {
                Items = result.Items.Select(Map).ToList()
            };
        }

        private Item Map(Dictionary<string, AttributeValue> result)
        {
            return new Item
            {
                productName = result["ProductName"].S,
                productQuantity = Convert.ToInt32(result["ProductQuantity"].N)
            };
        }

        private async Task<ScanResponse> ScanAsync(ScanRequest request)
        {
            var response = await _dynamoDbClient.ScanAsync(request);

            return response;
        }

        private ScanRequest RequestBuilder(string? productName)
        {
            if (productName.Length <= 0)
            {
                return new ScanRequest
                {
                    TableName = tableName
                };
            }

            return new ScanRequest
            {
                TableName = tableName,
                ExpressionAttributeValues = new Dictionary<string, AttributeValue> {
                    {
                        ":v_ProductName",  new AttributeValue { S = productName }
                    }

                },
                FilterExpression = "ProductName = :v_ProductName",
                ProjectionExpression = "ProductName, ProductQuantity"
            };
        }

    }
} 

AWSProductListDynamoDB.Libs – AWSProductListDynamoDB IUpdateItem.cs (Interface)

 using System.Threading.Tasks;
 using AWSProductListDynamoDb.Libs.Models;
 namespace AWSProductListDynamoDb.Libs.AWSProductListDynamoDb
 {
     public interface IUpdateItem
     {
         Task Update(string productName, int productQuantity);
     }
 }

AWSProductListDynamoDB.Libs – AWSProductListDynamoDB UpdateItem.cs (Altera os dados no banco de dados)

using Amazon.DynamoDBv2;
using Amazon.DynamoDBv2.Model;
using AWSProductListDynamoDb.Libs.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace AWSProductListDynamoDb.Libs.AWSProductListDynamoDb
{
    public class UpdateItem : IUpdateItem
    {
        private readonly IQueryItem _queryItem;
        private static readonly string tableName = Environment.GetEnvironmentVariable("AWS_CONTENT");
        private readonly IAmazonDynamoDB _dynamoDbClient;

        public UpdateItem(IQueryItem queryItem, IAmazonDynamoDB dynamoDbClient)
        {
            _queryItem = queryItem;
            _dynamoDbClient = dynamoDbClient;
        }

        public async Task<Item> Update(string productName, int productQuantity)
        {
            var response = await _queryItem.GetItems(productName);

            var currentQuantity = response.Items.Select(p => p.productQuantity).FirstOrDefault();

            var request = RequestBuilder(productName, productQuantity, currentQuantity);

            var result = await UpdateItemAsync(request);

            return new Item
            {
                productName = result.Attributes["ProductName"].S,
                productQuantity = Convert.ToInt32(result.Attributes["ProductQuantity"].N)
            };
        }

        private UpdateItemRequest RequestBuilder(string productName, int productQuantity, int currentQuantity)
        {
            var request = new UpdateItemRequest
            {
                Key = new Dictionary<string, AttributeValue>
                {
                    {
                        "ProductName", new AttributeValue
                        {
                            S = productName
                        }

                    }//,
                    //{
                    //    "ProductQuantity", new AttributeValue
                     //   {
                     //       N = currentQuantity.ToString()
                     //   }

                   // }
                },              
                ExpressionAttributeNames = new Dictionary<string, string>
                {
                    {"#P", "ProductQuantity"}
                },
                ExpressionAttributeValues = new Dictionary<string, AttributeValue>
                {
                    {
                        ":newquantity", new AttributeValue
                        {
                            N = productQuantity.ToString()
                        }
                    },
                    {   
                        ":currquantity", new AttributeValue
                        {
                            N = currentQuantity.ToString() 
                        }
                    }
                },

                UpdateExpression = "SET #P = :newquantity",
                ConditionExpression = "#P = :currquantity",

                TableName = tableName,
                ReturnValues = "ALL_NEW"
            };

            return request;
        }
        private async Task<UpdateItemResponse> UpdateItemAsync(UpdateItemRequest request)
        {
            var response = await _dynamoDbClient.UpdateItemAsync(request);

            return response;
        }
    }
} 

AWSProductListDynamoDB.Libs – AWSProductListDynamoDB IDeleteItem.cs (Interface)

 using System.Threading.Tasks;
 namespace AWSProductListDynamoDb.Libs.AWSProductListDynamoDb
 {
     public interface IDeleteItem
     {
         Task DeleteEntry(string productName, int productQuantity);
     }
 }

AWSProductListDynamoDB.Libs – AWSProductListDynamoDB DeleteItem.cs (Exclui dados do banco de dados)

using Amazon.DynamoDBv2;
using Amazon.DynamoDBv2.Model;
using System;
using System.Collections.Generic;
using System.Threading.Tasks;


namespace AWSProductListDynamoDb.Libs.AWSProductListDynamoDb
{
    public class DeleteItem : IDeleteItem
    {
        private static readonly string tableName = Environment.GetEnvironmentVariable("AWS_CONTENT");

        private readonly IAmazonDynamoDB _dynamoDbClient;
        public DeleteItem(IAmazonDynamoDB dynamoDbClient)
        {
            _dynamoDbClient = dynamoDbClient;
        }
        public async Task DeleteEntry(string productName, int productQuantity)
        {
            try
            {
                var queryRequest = RequestBuilder(productName, productQuantity);

                await DeleteItemAsync(queryRequest);
            }
            catch (InternalServerErrorException)
            {
                Console.WriteLine("Erro 1");
            }
            catch (ResourceNotFoundException)
            {
                Console.WriteLine("Erro 2");
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.InnerException.StackTrace.ToString());
            }

        }

        private DeleteItemRequest RequestBuilder(string productName, int productQuantity)
        {
            var item = new Dictionary<string, AttributeValue>
            {
                {"ProductName", new AttributeValue {S = productName}}
            };

            return new DeleteItemRequest
            {
                TableName = tableName,
                Key = item
            };
        }
        private async Task DeleteItemAsync(DeleteItemRequest request)
        {
            await _dynamoDbClient.DeleteItemAsync(request);
        }
    }
} 
 

Com todas as classes criadas em nosso projeto, vamos compilá-lo ! CTRL+SHIFT+B e depois F5 para executarmos ! 🙂

image 5

Agora é hora de testarmos. Vamos abrir o postman e começar !

Primeiramente vamos inserir um novo item: 1 Motherboard

Clique em Send e veja o resultado:

image 6

Sem erros ! Vejamos agora no DynamoDb:

image 8

Agora vamos alterar a quantidade do Monitor:

image 9
image 11

Agora vamos excluir o Keyboard:

image 12
image 13

E por último, vamos pesquisar o Mouse:

image 15

É isso aí pessoal ! Espero que esse artigo seja útil a vocês !

Abraço

Fontes

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5 comentários em “CRUD .NET Core e DynamoDB”

  1. Avatar de Anderson

    A parte de “criar um novo Projeto do tipo Class Library (.NET Core) chamado AWSProductListDynamoDb” ficou muito confuso. Os nomes dos projetos se repetem e do nada é para selecionar a opção “AWSProductListDynamoDb.Libs”, que até então não foi criada.

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