public async Task <APIGatewayProxyResponse> OnConnectHandler(APIGatewayProxyRequest request, ILambdaContext context)
{
try
{
var connectionId = request.RequestContext.ConnectionId;
context.Logger.LogLine($"ConnectionId: {connectionId}");
var ddbRequest = new PutItemRequest
{
TableName = ConnectionMappingTable,
Item = new Dictionary <string, AttributeValue>
{
{ ConnectionIdField, new AttributeValue {
S = connectionId
} }
}
};
await DdbClient.PutItemAsync(ddbRequest);
return(new APIGatewayProxyResponse
{
StatusCode = 200,
Body = "Connected."
});
}
catch (Exception e)
{
context.Logger.LogLine("Error connecting: " + e.Message);
context.Logger.LogLine(e.StackTrace);
return(new APIGatewayProxyResponse
{
StatusCode = 500,
Body = $"Failed to connect: {e.Message}"
});
}
}
public async Task <APIGatewayProxyResponse> PingPongHandler(APIGatewayProxyRequest request, ILambdaContext context)
{
try
{
var domainName = request.RequestContext.DomainName;
var stage = request.RequestContext.Stage;
var endpoint = $"https://{domainName}/{stage}";
var apiClient = ApiGatewayManagementApiClientFactory(endpoint);
context.Logger.LogLine($"API Gateway management endpoint: {endpoint}");
var connectionId = request.RequestContext.ConnectionId;
context.Logger.LogLine($"Ping from ConnectionId: {connectionId}");
var stream = new MemoryStream(Encoding.UTF8.GetBytes("{\"message\": \"pong\"}"));
var postConnectionRequest = new PostToConnectionRequest
{
ConnectionId = connectionId,
Data = stream
};
try
{
context.Logger.LogLine($"Reply pong to connection: {postConnectionRequest.ConnectionId}");
stream.Position = 0;
await apiClient.PostToConnectionAsync(postConnectionRequest);
}
catch (AmazonServiceException e)
{
// API Gateway returns a status of 410 GONE then the connection is no
// longer available. If this happens, delete the identifier
// from our DynamoDB table.
if (e.StatusCode == HttpStatusCode.Gone)
{
var ddbDeleteRequest = new DeleteItemRequest
{
TableName = ConnectionMappingTable,
Key = new Dictionary <string, AttributeValue>
{
{ ConnectionIdField, new AttributeValue {
S = postConnectionRequest.ConnectionId
} }
}
};
context.Logger.LogLine($"Deleting gone connection: {postConnectionRequest.ConnectionId}");
await DdbClient.DeleteItemAsync(ddbDeleteRequest);
}
else
{
context.Logger.LogLine($"Error posting message to {postConnectionRequest.ConnectionId}: {e.Message}");
context.Logger.LogLine(e.StackTrace);
}
}
return(new APIGatewayProxyResponse
{
StatusCode = (int)HttpStatusCode.OK,
Body = $"Pong sent to connection id {connectionId}"
});
}
catch (Exception e)
{
context.Logger.LogLine("Error ping/pong: " + e.Message);
context.Logger.LogLine(e.StackTrace);
return(new APIGatewayProxyResponse
{
StatusCode = (int)HttpStatusCode.InternalServerError,
Body = $"Failed to send message: {e.Message}"
});
}
}
public async Task <APIGatewayProxyResponse> SendMessageHandler(APIGatewayProxyRequest request, ILambdaContext context)
{
try
{
// Construct the API Gateway endpoint that incoming message will be broadcasted to.
var domainName = request.RequestContext.DomainName;
var stage = request.RequestContext.Stage;
var endpoint = $"https://{domainName}/{stage}";
context.Logger.LogLine($"API Gateway management endpoint: {endpoint}");
// The body will look something like this: {"message":"sendmessage", "data":"What are you doing?"}
var message = JsonDocument.Parse(request.Body);
// Grab the data from the JSON body which is the message to broadcasted.
if (!message.RootElement.TryGetProperty("data", out var dataProperty))
{
context.Logger.LogLine("Failed to find data element in JSON document");
return(new APIGatewayProxyResponse
{
StatusCode = (int)HttpStatusCode.BadRequest
});
}
var data = dataProperty.GetRawText();
context.Logger.LogLine($"Received data: {data}");
var stream = new MemoryStream(Encoding.UTF8.GetBytes(data));
// List all of the current connections. In a more advanced use case the table could be used to grab a group of connection ids for a chat group.
var scanRequest = new ScanRequest
{
TableName = ConnectionMappingTable,
ProjectionExpression = ConnectionIdField
};
var scanResponse = await DdbClient.ScanAsync(scanRequest);
// Construct the IAmazonApiGatewayManagementApi which will be used to send the message to.
var apiClient = ApiGatewayManagementApiClientFactory(endpoint);
// Loop through all of the connections and broadcast the message out to the connections.
var count = 0;
foreach (var item in scanResponse.Items)
{
var postConnectionRequest = new PostToConnectionRequest
{
ConnectionId = item[ConnectionIdField].S,
Data = stream
};
try
{
context.Logger.LogLine($"Post to connection {count}: {postConnectionRequest.ConnectionId}");
stream.Position = 0;
await apiClient.PostToConnectionAsync(postConnectionRequest);
count++;
}
catch (AmazonServiceException e)
{
// API Gateway returns a status of 410 GONE then the connection is no
// longer available. If this happens, delete the identifier
// from our DynamoDB table.
if (e.StatusCode == HttpStatusCode.Gone)
{
var ddbDeleteRequest = new DeleteItemRequest
{
TableName = ConnectionMappingTable,
Key = new Dictionary <string, AttributeValue>
{
{ ConnectionIdField, new AttributeValue {
S = postConnectionRequest.ConnectionId
} }
}
};
context.Logger.LogLine($"Deleting gone connection: {postConnectionRequest.ConnectionId}");
await DdbClient.DeleteItemAsync(ddbDeleteRequest);
}
else
{
context.Logger.LogLine($"Error posting message to {postConnectionRequest.ConnectionId}: {e.Message}");
context.Logger.LogLine(e.StackTrace);
}
}
}
return(new APIGatewayProxyResponse
{
StatusCode = (int)HttpStatusCode.OK,
Body = "Data sent to " + count + " connection" + (count == 1 ? "" : "s")
});
}
catch (Exception e)
{
context.Logger.LogLine("Error disconnecting: " + e.Message);
context.Logger.LogLine(e.StackTrace);
return(new APIGatewayProxyResponse
{
StatusCode = (int)HttpStatusCode.InternalServerError,
Body = $"Failed to send message: {e.Message}"
});
}
}
