matthiasxc/dynamodb-net-core-sample

A very simple .NET Core console app with DynamoDB

Getting Started With DynamoDB with C# (.NET Core)

This is a very simple .NET Core console app with DynamoDB. It verifies or creates a DynamoDB table, waits for that table to become active, then adds one document to the table and retrieves it.

The item stored in the database is modeled on the audio state item created in the Alexa Audio Player sample.

Nuget Package

AWSSDK Amazon DynamoDB

Search or type Install-Package AWSSDK.DynamoDBv2 into your Package Manager Console

Add the following namespaces

using Amazon;
using Amazon.DynamoDBv2;
using Amazon.DynamoDBv2.DataModel;
using Amazon.DynamoDBv2.DocumentModel;
using Amazon.DynamoDBv2.Model;
using Amazon.Runtime;

Set Your AWS Credentials

BasicAWSCredentials(accessKey, secretKey);
var client = new AmazonDynamoDBClient(credentials, RegionEndpoint.USEast1);

Verify a Table

var tableResponse = await client.ListTablesAsync();
if (!tableResponse.TableNames.Contains(tableName))
{
    // Create our table if it doesn't exist
}

Create a New Table

await client.CreateTableAsync(new CreateTableRequest
{
    TableName = tableName,
    ProvisionedThroughput = new ProvisionedThroughput
    {
        ReadCapacityUnits = 3,
        WriteCapacityUnits = 1
    },
    KeySchema = new List<KeySchemaElement>
    {
        new KeySchemaElement
        {
            AttributeName = hashKey,
            KeyType = KeyType.HASH
        }
    },
    AttributeDefinitions = new List<AttributeDefinition>
    {
        new AttributeDefinition {
            AttributeName = hashKey,
            AttributeType =ScalarAttributeType.S
        }
    }
});

Wait for New Table to Create / Become Active

bool isTableAvailable = false;
while (!isTableAvailable) {
    Thread.Sleep(5000);
    var tableStatus = await client.DescribeTableAsync(tableName);
    isTableAvailable = tableStatus.Table.TableStatus == "ACTIVE";
}

Set Your Context

var context = new DynamoDBContext(client);

Create an Object and Save It

// Create our audio state object
AlexaAudioState currentState = new AlexaAudioState
{
    UserId = "someAwesomeUser",
    State = new StateMap()
    {
        EnqueuedToken = "awesomeAudioPart2",
        Index = 0,
        Loop = true,
        OffsetInMS = 123456,
        PlaybackFinished = false,
        PlaybackIndexChanged = false,
        playOrder = new List<int> { 0, 1 },
        Shuffle = false,
        State = "PLAY_MODE",
        Token = "awesomeAudioPart1"
    }
};

// Save that object into our DynamoDB
await context.SaveAsync<AlexaAudioState>(currentState);

Retrieve a Document

List<ScanCondition> conditions = new List<ScanCondition>();
conditions.Add(new ScanCondition("UserId", ScanOperator.Equal, currentState.UserId));
var allDocs = await context.ScanAsync<AlexaAudioState>(conditions).GetRemainingAsync();
var savedState = allDocs.FirstOrDefault();

Delete a Table

context.Dispose();
await client.DeleteTableAsync(new DeleteTableRequest() { TableName = tableName });

dynamodb-net-core-sample's Issues

Question regarding object composition

Is there a reason that you put State in to object StateMap rather than just putting all the properties in to AlexAudioState? Is this required by DynamoDB or is this your design choice?

[DynamoDBTable("AlexaAudioStates")]
    public class AlexaAudioState
    {
        [DynamoDBHashKey]
        public string UserId { get; set; }
        public StateMap State { get; set; }

    }