Esempi di Amazon Keyspaces utilizzando AWS SDK for .NET

I seguenti esempi di codice mostrano come eseguire azioni e implementare scenari comuni utilizzando AWS SDK for .NET con Amazon Keyspaces.

Le operazioni sono estratti di codice da programmi più grandi e devono essere eseguite nel contesto. Sebbene le operazioni mostrino come richiamare le singole funzioni del servizio, è possibile visualizzarle contestualizzate negli scenari correlati e negli esempi tra servizi.

Scenari: esempi di codice che mostrano come eseguire un'attività specifica richiamando più funzioni all'interno dello stesso servizio.

Ogni esempio include un collegamento a GitHub, dove puoi trovare istruzioni su come configurare ed eseguire il codice nel contesto.

Nozioni di base

I seguenti esempi di codice mostrano come iniziare a utilizzare Amazon Keyspaces.

AWS SDK for .NET

Nota

C'è altro su. GitHub Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice AWS.


namespace KeyspacesActions;

public class HelloKeyspaces
{
    private static ILogger logger = null!;

    static async Task Main(string[] args)
    {
        // Set up dependency injection for Amazon Keyspaces (for Apache Cassandra).
        using var host = Host.CreateDefaultBuilder(args)
            .ConfigureLogging(logging =>
                logging.AddFilter("System", LogLevel.Debug)
                    .AddFilter<DebugLoggerProvider>("Microsoft", LogLevel.Information)
                    .AddFilter<ConsoleLoggerProvider>("Microsoft", LogLevel.Trace))
            .ConfigureServices((_, services) =>
                services.AddAWSService<IAmazonKeyspaces>()
                .AddTransient<KeyspacesWrapper>()
            )
            .Build();

        logger = LoggerFactory.Create(builder => { builder.AddConsole(); })
            .CreateLogger<HelloKeyspaces>();

        var keyspacesClient = host.Services.GetRequiredService<IAmazonKeyspaces>();
        var keyspacesWrapper = new KeyspacesWrapper(keyspacesClient);

        Console.WriteLine("Hello, Amazon Keyspaces! Let's list your keyspaces:");
        await keyspacesWrapper.ListKeyspaces();
    }
}

Per i dettagli sull'API, ListKeyspacesconsulta AWS SDK for .NET API Reference.

Azioni

Il seguente esempio di codice mostra come utilizzareCreateKeyspace.

AWS SDK for .NET

Nota

C'è altro da fare GitHub. Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice AWS.


    /// <summary>
    /// Create a new keyspace.
    /// </summary>
    /// <param name="keyspaceName">The name for the new keyspace.</param>
    /// <returns>The Amazon Resource Name (ARN) of the new keyspace.</returns>
    public async Task<string> CreateKeyspace(string keyspaceName)
    {
        var response =
            await _amazonKeyspaces.CreateKeyspaceAsync(
                new CreateKeyspaceRequest { KeyspaceName = keyspaceName });
        return response.ResourceArn;
    }

Per i dettagli sull'API, CreateKeyspaceconsulta AWS SDK for .NET API Reference.

Il seguente esempio di codice mostra come utilizzareCreateTable.

AWS SDK for .NET

Nota

C'è altro da fare GitHub. Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice AWS.


    /// <summary>
    /// Create a new Amazon Keyspaces table.
    /// </summary>
    /// <param name="keyspaceName">The keyspace where the table will be created.</param>
    /// <param name="schema">The schema for the new table.</param>
    /// <param name="tableName">The name of the new table.</param>
    /// <returns>The Amazon Resource Name (ARN) of the new table.</returns>
    public async Task<string> CreateTable(string keyspaceName, SchemaDefinition schema, string tableName)
    {
        var request = new CreateTableRequest
        {
            KeyspaceName = keyspaceName,
            SchemaDefinition = schema,
            TableName = tableName,
            PointInTimeRecovery = new PointInTimeRecovery { Status = PointInTimeRecoveryStatus.ENABLED }
        };

        var response = await _amazonKeyspaces.CreateTableAsync(request);
        return response.ResourceArn;
    }

Per i dettagli sull'API, CreateTableconsulta AWS SDK for .NET API Reference.

Il seguente esempio di codice mostra come utilizzareDeleteKeyspace.

AWS SDK for .NET

Nota

C'è altro da fare GitHub. Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice AWS.


    /// <summary>
    /// Delete an existing keyspace.
    /// </summary>
    /// <param name="keyspaceName"></param>
    /// <returns>A Boolean value indicating the success of the action.</returns>
    public async Task<bool> DeleteKeyspace(string keyspaceName)
    {
        var response = await _amazonKeyspaces.DeleteKeyspaceAsync(
            new DeleteKeyspaceRequest { KeyspaceName = keyspaceName });
        return response.HttpStatusCode == HttpStatusCode.OK;
    }

Per i dettagli sull'API, DeleteKeyspaceconsulta AWS SDK for .NET API Reference.

Il seguente esempio di codice mostra come utilizzareDeleteTable.

AWS SDK for .NET

Nota

C'è altro da fare GitHub. Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice AWS.


    /// <summary>
    /// Delete an Amazon Keyspaces table.
    /// </summary>
    /// <param name="keyspaceName">The keyspace containing the table.</param>
    /// <param name="tableName">The name of the table to delete.</param>
    /// <returns>A Boolean value indicating the success of the action.</returns>
    public async Task<bool> DeleteTable(string keyspaceName, string tableName)
    {
        var response = await _amazonKeyspaces.DeleteTableAsync(
            new DeleteTableRequest { KeyspaceName = keyspaceName, TableName = tableName });
        return response.HttpStatusCode == HttpStatusCode.OK;
    }

Per i dettagli sull'API, DeleteTableconsulta AWS SDK for .NET API Reference.

Il seguente esempio di codice mostra come utilizzareGetKeyspace.

AWS SDK for .NET

Nota

C'è altro da fare GitHub. Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice AWS.


    /// <summary>
    /// Get data about a keyspace.
    /// </summary>
    /// <param name="keyspaceName">The name of the keyspace.</param>
    /// <returns>The Amazon Resource Name (ARN) of the keyspace.</returns>
    public async Task<string> GetKeyspace(string keyspaceName)
    {
        var response = await _amazonKeyspaces.GetKeyspaceAsync(
            new GetKeyspaceRequest { KeyspaceName = keyspaceName });
        return response.ResourceArn;
    }

Per i dettagli sull'API, GetKeyspaceconsulta AWS SDK for .NET API Reference.

Il seguente esempio di codice mostra come utilizzareGetTable.

AWS SDK for .NET

Nota

C'è altro da fare GitHub. Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice AWS.


    /// <summary>
    /// Get information about an Amazon Keyspaces table.
    /// </summary>
    /// <param name="keyspaceName">The keyspace containing the table.</param>
    /// <param name="tableName">The name of the Amazon Keyspaces table.</param>
    /// <returns>The response containing data about the table.</returns>
    public async Task<GetTableResponse> GetTable(string keyspaceName, string tableName)
    {
        var response = await _amazonKeyspaces.GetTableAsync(
            new GetTableRequest { KeyspaceName = keyspaceName, TableName = tableName });
        return response;
    }

Per i dettagli sull'API, GetTableconsulta AWS SDK for .NET API Reference.

Il seguente esempio di codice mostra come utilizzareListKeyspaces.

AWS SDK for .NET

Nota

C'è altro da fare GitHub. Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice AWS.


    /// <summary>
    /// Lists all keyspaces for the account.
    /// </summary>
    /// <returns>Async task.</returns>
    public async Task ListKeyspaces()
    {
        var paginator = _amazonKeyspaces.Paginators.ListKeyspaces(new ListKeyspacesRequest());

        Console.WriteLine("{0, -30}\t{1}", "Keyspace name", "Keyspace ARN");
        Console.WriteLine(new string('-', Console.WindowWidth));
        await foreach (var keyspace in paginator.Keyspaces)
        {
            Console.WriteLine($"{keyspace.KeyspaceName,-30}\t{keyspace.ResourceArn}");
        }
    }

Per i dettagli sull'API, ListKeyspacesconsulta AWS SDK for .NET API Reference.

Il seguente esempio di codice mostra come utilizzareListTables.

AWS SDK for .NET

Nota

C'è altro da fare GitHub. Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice AWS.


    /// <summary>
    /// Lists the Amazon Keyspaces tables in a keyspace.
    /// </summary>
    /// <param name="keyspaceName">The name of the keyspace.</param>
    /// <returns>A list of TableSummary objects.</returns>
    public async Task<List<TableSummary>> ListTables(string keyspaceName)
    {
        var response = await _amazonKeyspaces.ListTablesAsync(new ListTablesRequest { KeyspaceName = keyspaceName });
        response.Tables.ForEach(table =>
        {
            Console.WriteLine($"{table.KeyspaceName}\t{table.TableName}\t{table.ResourceArn}");
        });

        return response.Tables;
    }

Per i dettagli sull'API, ListTablesconsulta AWS SDK for .NET API Reference.

Il seguente esempio di codice mostra come utilizzareRestoreTable.

AWS SDK for .NET

Nota

C'è altro da fare GitHub. Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice AWS.


    /// <summary>
    /// Restores the specified table to the specified point in time.
    /// </summary>
    /// <param name="keyspaceName">The keyspace containing the table.</param>
    /// <param name="tableName">The name of the table to restore.</param>
    /// <param name="timestamp">The time to which the table will be restored.</param>
    /// <returns>The Amazon Resource Name (ARN) of the restored table.</returns>
    public async Task<string> RestoreTable(string keyspaceName, string tableName, string restoredTableName, DateTime timestamp)
    {
        var request = new RestoreTableRequest
        {
            RestoreTimestamp = timestamp,
            SourceKeyspaceName = keyspaceName,
            SourceTableName = tableName,
            TargetKeyspaceName = keyspaceName,
            TargetTableName = restoredTableName
        };

        var response = await _amazonKeyspaces.RestoreTableAsync(request);
        return response.RestoredTableARN;
    }

Per i dettagli sull'API, RestoreTableconsulta AWS SDK for .NET API Reference.

Il seguente esempio di codice mostra come utilizzareUpdateTable.

AWS SDK for .NET

Nota

C'è altro da fare GitHub. Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice AWS.


    /// <summary>
    /// Updates the movie table to add a boolean column named watched.
    /// </summary>
    /// <param name="keyspaceName">The keyspace containing the table.</param>
    /// <param name="tableName">The name of the table to change.</param>
    /// <returns>The Amazon Resource Name (ARN) of the updated table.</returns>
    public async Task<string> UpdateTable(string keyspaceName, string tableName)
    {
        var newColumn = new ColumnDefinition { Name = "watched", Type = "boolean" };
        var request = new UpdateTableRequest
        {
            KeyspaceName = keyspaceName,
            TableName = tableName,
            AddColumns = new List<ColumnDefinition> { newColumn }
        };
        var response = await _amazonKeyspaces.UpdateTableAsync(request);
        return response.ResourceArn;
    }

Per i dettagli sull'API, UpdateTableconsulta AWS SDK for .NET API Reference.

Scenari

L'esempio di codice seguente mostra come:

Crea uno spazio chiave e una tabella. Lo schema della tabella contiene i dati dei film e il point-in-time ripristino è abilitato.
Connect al keyspace utilizzando una connessione TLS sicura con autenticazione SigV4.
Esegui una query sulla tabella. Aggiungi, recupera e aggiorna i dati dei film.
Aggiorna la tabella. Aggiungi una colonna per tenere traccia dei film guardati.
Ripristina lo stato precedente della tabella e ripulisci le risorse.

AWS SDK for .NET

Nota

C'è altro da fare GitHub. Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice AWS.


global using System.Security.Cryptography.X509Certificates;
global using Amazon.Keyspaces;
global using Amazon.Keyspaces.Model;
global using KeyspacesActions;
global using KeyspacesScenario;
global using Microsoft.Extensions.Configuration;
global using Microsoft.Extensions.DependencyInjection;
global using Microsoft.Extensions.Hosting;
global using Microsoft.Extensions.Logging;
global using Microsoft.Extensions.Logging.Console;
global using Microsoft.Extensions.Logging.Debug;
global using Newtonsoft.Json;


namespace KeyspacesBasics;

/// <summary>
/// Amazon Keyspaces (for Apache Cassandra) scenario. Shows some of the basic
/// actions performed with Amazon Keyspaces.
/// </summary>
public class KeyspacesBasics
{
    private static ILogger logger = null!;

    static async Task Main(string[] args)
    {
        // Set up dependency injection for the Amazon service.
        using var host = Host.CreateDefaultBuilder(args)
            .ConfigureLogging(logging =>
                logging.AddFilter("System", LogLevel.Debug)
                    .AddFilter<DebugLoggerProvider>("Microsoft", LogLevel.Information)
                    .AddFilter<ConsoleLoggerProvider>("Microsoft", LogLevel.Trace))
            .ConfigureServices((_, services) =>
            services.AddAWSService<IAmazonKeyspaces>()
            .AddTransient<KeyspacesWrapper>()
            .AddTransient<CassandraWrapper>()
            )
            .Build();

        logger = LoggerFactory.Create(builder => { builder.AddConsole(); })
            .CreateLogger<KeyspacesBasics>();

        var configuration = new ConfigurationBuilder()
            .SetBasePath(Directory.GetCurrentDirectory())
            .AddJsonFile("settings.json") // Load test settings from .json file.
            .AddJsonFile("settings.local.json",
                true) // Optionally load local settings.
            .Build();

        var keyspacesWrapper = host.Services.GetRequiredService<KeyspacesWrapper>();
        var uiMethods = new UiMethods();

        var keyspaceName = configuration["KeyspaceName"];
        var tableName = configuration["TableName"];

        bool success; // Used to track the results of some operations.

        uiMethods.DisplayOverview();
        uiMethods.PressEnter();

        // Create the keyspace.
        var keyspaceArn = await keyspacesWrapper.CreateKeyspace(keyspaceName);

        // Wait for the keyspace to be available. GetKeyspace results in a
        // resource not found error until it is ready for use.
        try
        {
            var getKeyspaceArn = "";
            Console.Write($"Created {keyspaceName}. Waiting for it to become available. ");
            do
            {
                getKeyspaceArn = await keyspacesWrapper.GetKeyspace(keyspaceName);
                Console.Write(". ");
            } while (getKeyspaceArn != keyspaceArn);
        }
        catch (ResourceNotFoundException)
        {
            Console.WriteLine("Waiting for keyspace to be created.");
        }

        Console.WriteLine($"\nThe keyspace {keyspaceName} is ready for use.");

        uiMethods.PressEnter();

        // Create the table.
        // First define the schema.
        var allColumns = new List<ColumnDefinition>
        {
            new ColumnDefinition { Name = "title", Type = "text" },
            new ColumnDefinition { Name = "year", Type = "int" },
            new ColumnDefinition { Name = "release_date", Type = "timestamp" },
            new ColumnDefinition { Name = "plot", Type = "text" },
        };

        var partitionKeys = new List<PartitionKey>
        {
            new PartitionKey { Name = "year", },
            new PartitionKey { Name = "title" },
        };

        var tableSchema = new SchemaDefinition
        {
            AllColumns = allColumns,
            PartitionKeys = partitionKeys,
        };

        var tableArn = await keyspacesWrapper.CreateTable(keyspaceName, tableSchema, tableName);

        // Wait for the table to be active.
        try
        {
            var resp = new GetTableResponse();
            Console.Write("Waiting for the new table to be active. ");
            do
            {
                try
                {
                    resp = await keyspacesWrapper.GetTable(keyspaceName, tableName);
                    Console.Write(".");
                }
                catch (ResourceNotFoundException)
                {
                    Console.Write(".");
                }
            } while (resp.Status != TableStatus.ACTIVE);

            // Display the table's schema.
            Console.WriteLine($"\nTable {tableName} has been created in {keyspaceName}");
            Console.WriteLine("Let's take a look at the schema.");
            uiMethods.DisplayTitle("All columns");
            resp.SchemaDefinition.AllColumns.ForEach(column =>
            {
                Console.WriteLine($"{column.Name,-40}\t{column.Type,-20}");
            });

            uiMethods.DisplayTitle("Cluster keys");
            resp.SchemaDefinition.ClusteringKeys.ForEach(clusterKey =>
            {
                Console.WriteLine($"{clusterKey.Name,-40}\t{clusterKey.OrderBy,-20}");
            });

            uiMethods.DisplayTitle("Partition keys");
            resp.SchemaDefinition.PartitionKeys.ForEach(partitionKey =>
            {
                Console.WriteLine($"{partitionKey.Name}");
            });

            uiMethods.PressEnter();
        }
        catch (ResourceNotFoundException ex)
        {
            Console.WriteLine($"Error: {ex.Message}");
        }

        // Access Apache Cassandra using the Cassandra drive for C#.
        var cassandraWrapper = host.Services.GetRequiredService<CassandraWrapper>();
        var movieFilePath = configuration["MovieFile"];

        Console.WriteLine("Let's add some movies to the table we created.");
        var inserted = await cassandraWrapper.InsertIntoMovieTable(keyspaceName, tableName, movieFilePath);

        uiMethods.PressEnter();

        Console.WriteLine("Added the following movies to the table:");
        var rows = await cassandraWrapper.GetMovies(keyspaceName, tableName);
        uiMethods.DisplayTitle("All Movies");

        foreach (var row in rows)
        {
            var title = row.GetValue<string>("title");
            var year = row.GetValue<int>("year");
            var plot = row.GetValue<string>("plot");
            var release_date = row.GetValue<DateTime>("release_date");
            Console.WriteLine($"{release_date}\t{title}\t{year}\n{plot}");
            Console.WriteLine(uiMethods.SepBar);
        }

        // Update the table schema
        uiMethods.DisplayTitle("Update table schema");
        Console.WriteLine("Now we will update the table to add a boolean field called watched.");

        // First save the current time as a UTC Date so the original
        // table can be restored later.
        var timeChanged = DateTime.UtcNow;

        // Now update the schema.
        var resourceArn = await keyspacesWrapper.UpdateTable(keyspaceName, tableName);
        uiMethods.PressEnter();

        Console.WriteLine("Now let's mark some of the movies as watched.");

        // Pick some files to mark as watched.
        var movieToWatch = rows[2].GetValue<string>("title");
        var watchedMovieYear = rows[2].GetValue<int>("year");
        var changedRows = await cassandraWrapper.MarkMovieAsWatched(keyspaceName, tableName, movieToWatch, watchedMovieYear);

        movieToWatch = rows[6].GetValue<string>("title");
        watchedMovieYear = rows[6].GetValue<int>("year");
        changedRows = await cassandraWrapper.MarkMovieAsWatched(keyspaceName, tableName, movieToWatch, watchedMovieYear);

        movieToWatch = rows[9].GetValue<string>("title");
        watchedMovieYear = rows[9].GetValue<int>("year");
        changedRows = await cassandraWrapper.MarkMovieAsWatched(keyspaceName, tableName, movieToWatch, watchedMovieYear);

        movieToWatch = rows[10].GetValue<string>("title");
        watchedMovieYear = rows[10].GetValue<int>("year");
        changedRows = await cassandraWrapper.MarkMovieAsWatched(keyspaceName, tableName, movieToWatch, watchedMovieYear);

        movieToWatch = rows[13].GetValue<string>("title");
        watchedMovieYear = rows[13].GetValue<int>("year");
        changedRows = await cassandraWrapper.MarkMovieAsWatched(keyspaceName, tableName, movieToWatch, watchedMovieYear);

        uiMethods.DisplayTitle("Watched movies");
        Console.WriteLine("These movies have been marked as watched:");
        rows = await cassandraWrapper.GetWatchedMovies(keyspaceName, tableName);
        foreach (var row in rows)
        {
            var title = row.GetValue<string>("title");
            var year = row.GetValue<int>("year");
            Console.WriteLine($"{title,-40}\t{year,8}");
        }
        uiMethods.PressEnter();

        Console.WriteLine("We can restore the table to its previous state but that can take up to 20 minutes to complete.");
        string answer;
        do
        {
            Console.WriteLine("Do you want to restore the table? (y/n)");
            answer = Console.ReadLine();
        } while (answer.ToLower() != "y" && answer.ToLower() != "n");

        if (answer == "y")
        {
            var restoredTableName = $"{tableName}_restored";
            var restoredTableArn = await keyspacesWrapper.RestoreTable(
                keyspaceName,
                tableName,
                restoredTableName,
                timeChanged);
            // Loop and call GetTable until the table is gone. Once it has been
            // deleted completely, GetTable will raise a ResourceNotFoundException.
            bool wasRestored = false;

            try
            {
                do
                {
                    var resp = await keyspacesWrapper.GetTable(keyspaceName, restoredTableName);
                    wasRestored = (resp.Status == TableStatus.ACTIVE);
                } while (!wasRestored);
            }
            catch (ResourceNotFoundException)
            {
                // If the restored table raised an error, it isn't
                // ready yet.
                Console.Write(".");
            }
        }

        uiMethods.DisplayTitle("Clean up resources.");

        // Delete the table.
        success = await keyspacesWrapper.DeleteTable(keyspaceName, tableName);

        Console.WriteLine($"Table {tableName} successfully deleted from {keyspaceName}.");
        Console.WriteLine("Waiting for the table to be removed completely. ");

        // Loop and call GetTable until the table is gone. Once it has been
        // deleted completely, GetTable will raise a ResourceNotFoundException.
        bool wasDeleted = false;

        try
        {
            do
            {
                var resp = await keyspacesWrapper.GetTable(keyspaceName, tableName);
            } while (!wasDeleted);
        }
        catch (ResourceNotFoundException ex)
        {
            wasDeleted = true;
            Console.WriteLine($"{ex.Message} indicates that the table has been deleted.");
        }

        // Delete the keyspace.
        success = await keyspacesWrapper.DeleteKeyspace(keyspaceName);
        Console.WriteLine("The keyspace has been deleted and the demo is now complete.");
    }
}


namespace KeyspacesActions;

/// <summary>
/// Performs Amazon Keyspaces (for Apache Cassandra) actions.
/// </summary>
public class KeyspacesWrapper
{
    private readonly IAmazonKeyspaces _amazonKeyspaces;

    /// <summary>
    /// Constructor for the KeyspaceWrapper.
    /// </summary>
    /// <param name="amazonKeyspaces">An Amazon Keyspaces client object.</param>
    public KeyspacesWrapper(IAmazonKeyspaces amazonKeyspaces)
    {
        _amazonKeyspaces = amazonKeyspaces;
    }

    /// <summary>
    /// Create a new keyspace.
    /// </summary>
    /// <param name="keyspaceName">The name for the new keyspace.</param>
    /// <returns>The Amazon Resource Name (ARN) of the new keyspace.</returns>
    public async Task<string> CreateKeyspace(string keyspaceName)
    {
        var response =
            await _amazonKeyspaces.CreateKeyspaceAsync(
                new CreateKeyspaceRequest { KeyspaceName = keyspaceName });
        return response.ResourceArn;
    }


    /// <summary>
    /// Create a new Amazon Keyspaces table.
    /// </summary>
    /// <param name="keyspaceName">The keyspace where the table will be created.</param>
    /// <param name="schema">The schema for the new table.</param>
    /// <param name="tableName">The name of the new table.</param>
    /// <returns>The Amazon Resource Name (ARN) of the new table.</returns>
    public async Task<string> CreateTable(string keyspaceName, SchemaDefinition schema, string tableName)
    {
        var request = new CreateTableRequest
        {
            KeyspaceName = keyspaceName,
            SchemaDefinition = schema,
            TableName = tableName,
            PointInTimeRecovery = new PointInTimeRecovery { Status = PointInTimeRecoveryStatus.ENABLED }
        };

        var response = await _amazonKeyspaces.CreateTableAsync(request);
        return response.ResourceArn;
    }


    /// <summary>
    /// Delete an existing keyspace.
    /// </summary>
    /// <param name="keyspaceName"></param>
    /// <returns>A Boolean value indicating the success of the action.</returns>
    public async Task<bool> DeleteKeyspace(string keyspaceName)
    {
        var response = await _amazonKeyspaces.DeleteKeyspaceAsync(
            new DeleteKeyspaceRequest { KeyspaceName = keyspaceName });
        return response.HttpStatusCode == HttpStatusCode.OK;
    }


    /// <summary>
    /// Delete an Amazon Keyspaces table.
    /// </summary>
    /// <param name="keyspaceName">The keyspace containing the table.</param>
    /// <param name="tableName">The name of the table to delete.</param>
    /// <returns>A Boolean value indicating the success of the action.</returns>
    public async Task<bool> DeleteTable(string keyspaceName, string tableName)
    {
        var response = await _amazonKeyspaces.DeleteTableAsync(
            new DeleteTableRequest { KeyspaceName = keyspaceName, TableName = tableName });
        return response.HttpStatusCode == HttpStatusCode.OK;
    }


    /// <summary>
    /// Get data about a keyspace.
    /// </summary>
    /// <param name="keyspaceName">The name of the keyspace.</param>
    /// <returns>The Amazon Resource Name (ARN) of the keyspace.</returns>
    public async Task<string> GetKeyspace(string keyspaceName)
    {
        var response = await _amazonKeyspaces.GetKeyspaceAsync(
            new GetKeyspaceRequest { KeyspaceName = keyspaceName });
        return response.ResourceArn;
    }


    /// <summary>
    /// Get information about an Amazon Keyspaces table.
    /// </summary>
    /// <param name="keyspaceName">The keyspace containing the table.</param>
    /// <param name="tableName">The name of the Amazon Keyspaces table.</param>
    /// <returns>The response containing data about the table.</returns>
    public async Task<GetTableResponse> GetTable(string keyspaceName, string tableName)
    {
        var response = await _amazonKeyspaces.GetTableAsync(
            new GetTableRequest { KeyspaceName = keyspaceName, TableName = tableName });
        return response;
    }


    /// <summary>
    /// Lists all keyspaces for the account.
    /// </summary>
    /// <returns>Async task.</returns>
    public async Task ListKeyspaces()
    {
        var paginator = _amazonKeyspaces.Paginators.ListKeyspaces(new ListKeyspacesRequest());

        Console.WriteLine("{0, -30}\t{1}", "Keyspace name", "Keyspace ARN");
        Console.WriteLine(new string('-', Console.WindowWidth));
        await foreach (var keyspace in paginator.Keyspaces)
        {
            Console.WriteLine($"{keyspace.KeyspaceName,-30}\t{keyspace.ResourceArn}");
        }
    }


    /// <summary>
    /// Lists the Amazon Keyspaces tables in a keyspace.
    /// </summary>
    /// <param name="keyspaceName">The name of the keyspace.</param>
    /// <returns>A list of TableSummary objects.</returns>
    public async Task<List<TableSummary>> ListTables(string keyspaceName)
    {
        var response = await _amazonKeyspaces.ListTablesAsync(new ListTablesRequest { KeyspaceName = keyspaceName });
        response.Tables.ForEach(table =>
        {
            Console.WriteLine($"{table.KeyspaceName}\t{table.TableName}\t{table.ResourceArn}");
        });

        return response.Tables;
    }


    /// <summary>
    /// Restores the specified table to the specified point in time.
    /// </summary>
    /// <param name="keyspaceName">The keyspace containing the table.</param>
    /// <param name="tableName">The name of the table to restore.</param>
    /// <param name="timestamp">The time to which the table will be restored.</param>
    /// <returns>The Amazon Resource Name (ARN) of the restored table.</returns>
    public async Task<string> RestoreTable(string keyspaceName, string tableName, string restoredTableName, DateTime timestamp)
    {
        var request = new RestoreTableRequest
        {
            RestoreTimestamp = timestamp,
            SourceKeyspaceName = keyspaceName,
            SourceTableName = tableName,
            TargetKeyspaceName = keyspaceName,
            TargetTableName = restoredTableName
        };

        var response = await _amazonKeyspaces.RestoreTableAsync(request);
        return response.RestoredTableARN;
    }


    /// <summary>
    /// Updates the movie table to add a boolean column named watched.
    /// </summary>
    /// <param name="keyspaceName">The keyspace containing the table.</param>
    /// <param name="tableName">The name of the table to change.</param>
    /// <returns>The Amazon Resource Name (ARN) of the updated table.</returns>
    public async Task<string> UpdateTable(string keyspaceName, string tableName)
    {
        var newColumn = new ColumnDefinition { Name = "watched", Type = "boolean" };
        var request = new UpdateTableRequest
        {
            KeyspaceName = keyspaceName,
            TableName = tableName,
            AddColumns = new List<ColumnDefinition> { newColumn }
        };
        var response = await _amazonKeyspaces.UpdateTableAsync(request);
        return response.ResourceArn;
    }

}


using System.Net;
using Cassandra;

namespace KeyspacesScenario;

/// <summary>
/// Class to perform CRUD methods on an Amazon Keyspaces (for Apache Cassandra) database.
///
/// NOTE: This sample uses a plain text authenticator for example purposes only.
/// Recommended best practice is to use a SigV4 authentication plugin, if available.
/// </summary>
public class CassandraWrapper
{
    private readonly IConfiguration _configuration;
    private readonly string _localPathToFile;
    private const string _certLocation = "https://certs.secureserver.net/repository/sf-class2-root.crt";
    private const string _certFileName = "sf-class2-root.crt";
    private readonly X509Certificate2Collection _certCollection;
    private X509Certificate2 _amazoncert;
    private Cluster _cluster;

    // User name and password for the service.
    private string _userName = null!;
    private string _pwd = null!;

    public CassandraWrapper()
    {
        _configuration = new ConfigurationBuilder()
            .SetBasePath(Directory.GetCurrentDirectory())
            .AddJsonFile("settings.json") // Load test settings from .json file.
            .AddJsonFile("settings.local.json",
                true) // Optionally load local settings.
            .Build();

        _localPathToFile = Path.GetTempPath();

        // Get the Starfield digital certificate and save it locally.
        var client = new WebClient();
        client.DownloadFile(_certLocation, $"{_localPathToFile}/{_certFileName}");

        //var httpClient = new HttpClient();
        //var httpResult = httpClient.Get(fileUrl);
        //using var resultStream = await httpResult.Content.ReadAsStreamAsync();
        //using var fileStream = File.Create(pathToSave);
        //resultStream.CopyTo(fileStream);

        _certCollection = new X509Certificate2Collection();
        _amazoncert = new X509Certificate2($"{_localPathToFile}/{_certFileName}");

        // Get the user name and password stored in the configuration file.
        _userName = _configuration["UserName"]!;
        _pwd = _configuration["Password"]!;

        // For a list of Service Endpoints for Amazon Keyspaces, see:
        // https://docs.aws.amazon.com/keyspaces/latest/devguide/programmatic.endpoints.html
        var awsEndpoint = _configuration["ServiceEndpoint"];

        _cluster = Cluster.Builder()
            .AddContactPoints(awsEndpoint)
            .WithPort(9142)
            .WithAuthProvider(new PlainTextAuthProvider(_userName, _pwd))
            .WithSSL(new SSLOptions().SetCertificateCollection(_certCollection))
            .WithQueryOptions(
                new QueryOptions()
                    .SetConsistencyLevel(ConsistencyLevel.LocalQuorum)
                    .SetSerialConsistencyLevel(ConsistencyLevel.LocalSerial))
            .Build();
    }

    /// <summary>
    /// Loads the contents of a JSON file into a list of movies to be
    /// added to the Apache Cassandra table.
    /// </summary>
    /// <param name="movieFileName">The full path to the JSON file.</param>
    /// <returns>A list of movie objects.</returns>
    public List<Movie> ImportMoviesFromJson(string movieFileName, int numToImport = 0)
    {
        if (!File.Exists(movieFileName))
        {
            return null!;
        }

        using var sr = new StreamReader(movieFileName);
        string json = sr.ReadToEnd();

        var allMovies = JsonConvert.DeserializeObject<List<Movie>>(json);

        // If numToImport = 0, return all movies in the collection.
        if (numToImport == 0)
        {
            // Now return the entire list of movies.
            return allMovies;
        }
        else
        {
            // Now return the first numToImport entries.
            return allMovies.GetRange(0, numToImport);
        }
    }

    /// <summary>
    /// Insert movies into the movie table.
    /// </summary>
    /// <param name="keyspaceName">The keyspace containing the table.</param>
    /// <param name="movieTableName">The Amazon Keyspaces table.</param>
    /// <param name="movieFilePath">The path to the resource file containing
    /// movie data to insert into the table.</param>
    /// <returns>A Boolean value indicating the success of the action.</returns>
    public async Task<bool> InsertIntoMovieTable(string keyspaceName, string movieTableName, string movieFilePath, int numToImport = 20)
    {
        // Get some movie data from the movies.json file
        var movies = ImportMoviesFromJson(movieFilePath, numToImport);

        var session = _cluster.Connect(keyspaceName);

        string insertCql;

        RowSet rs;

        // Now we insert the numToImport movies into the table.
        foreach (var movie in movies)
        {
            // Escape single quote characters in the plot.
            insertCql = $"INSERT INTO {keyspaceName}.{movieTableName} (title, year, release_date, plot) values($${movie.Title}$$, {movie.Year}, '{movie.Info.Release_Date.ToString("yyyy-MM-dd")}', $${movie.Info.Plot}$$)";
            rs = await session.ExecuteAsync(new SimpleStatement(insertCql));
        }

        return true;
    }

    /// <summary>
    /// Gets all of the movies in the movies table.
    /// </summary>
    /// <param name="keyspaceName">The keyspace containing the table.</param>
    /// <param name="tableName">The name of the table.</param>
    /// <returns>A list of row objects containing movie data.</returns>
    public async Task<List<Row>> GetMovies(string keyspaceName, string tableName)
    {
        var session = _cluster.Connect();
        RowSet rs;
        try
        {
            rs = await session.ExecuteAsync(new SimpleStatement($"SELECT * FROM {keyspaceName}.{tableName}"));

            // Extract the row data from the returned RowSet.
            var rows = rs.GetRows().ToList();
            return rows;
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
            return null!;
        }
    }

    /// <summary>
    /// Mark a movie in the movie table as watched.
    /// </summary>
    /// <param name="keyspaceName">The keyspace containing the table.</param>
    /// <param name="tableName">The name of the table.</param>
    /// <param name="title">The title of the movie to mark as watched.</param>
    /// <param name="year">The year the movie was released.</param>
    /// <returns>A set of rows containing the changed data.</returns>
    public async Task<List<Row>> MarkMovieAsWatched(string keyspaceName, string tableName, string title, int year)
    {
        var session = _cluster.Connect();
        string updateCql = $"UPDATE {keyspaceName}.{tableName} SET watched=true WHERE title = $${title}$$ AND year = {year};";
        var rs = await session.ExecuteAsync(new SimpleStatement(updateCql));
        var rows = rs.GetRows().ToList();
        return rows;
    }

    /// <summary>
    /// Retrieve the movies in the movies table where watched is true.
    /// </summary>
    /// <param name="keyspaceName">The keyspace containing the table.</param>
    /// <param name="tableName">The name of the table.</param>
    /// <returns>A list of row objects containing information about movies
    /// where watched is true.</returns>
    public async Task<List<Row>> GetWatchedMovies(string keyspaceName, string tableName)
    {
        var session = _cluster.Connect();
        RowSet rs;
        try
        {
            rs = await session.ExecuteAsync(new SimpleStatement($"SELECT title, year, plot FROM {keyspaceName}.{tableName} WHERE watched = true ALLOW FILTERING"));

            // Extract the row data from the returned RowSet.
            var rows = rs.GetRows().ToList();
            return rows;
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
            return null!;
        }
    }
}

Per informazioni dettagliate sull'API, consulta i seguenti argomenti nella Documentazione di riferimento delle API AWS SDK for .NET .

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