private Product MapToContract(ProductTableEntity productTableEntity)
{
return(new Product
{
Id = productTableEntity.Id,
Name = productTableEntity.Name,
Price = productTableEntity.Price,
});
}
/// <summary>
/// Event handler that listens for PrdouctChanged Events from the catalog service
/// and synchronizes the Catalog Read Table in BasketEntity accordingly.
/// Handles both productEntity inserts and updates.
/// </summary>
/// <param name="productEntity">ProductEntity Information</param>
/// <param name="correlationId">Tracks request - can be any value</param>
/// <returns></returns>
public async Task ProductChanged(ProductEntity productEntity, string correlationId)
{
if (productEntity == null)
{
_logger.LogWarning($"Missing productEntity information for synchronization event in BasketEntity");
throw new Exception($"Missing productEntity information for synchronization event in BasketEntity");
}
// Transform to ProductTableEntity objects
var productTableEntity = new ProductTableEntity
{
PartitionKey = ProductPartitionKey,
RowKey = productEntity.Id.ToString(),
Title = productEntity.Title,
ArtistName = productEntity.ArtistName,
GenreName = productEntity.GenreName,
Price = productEntity.Price.ToString(),
//Upc = productEntity.Upc
};
try
{
// Determine if record already exists
var currentReadTableItems =
await _productRepository.GetItem(ProductPartitionKey,
productTableEntity.RowKey, correlationId);
if (currentReadTableItems == null)
{
// Insert resource
await _productRepository.Insert(productTableEntity, correlationId);
_logger.LogInformation(
$"Inserting ProductEntity {productEntity.Id}, {productTableEntity.Title} into Catalog ReadModel for Request {correlationId}");
}
else
{
// Update resource
await _productRepository.Update(productTableEntity, correlationId);
_logger.LogInformation(
$"Updating ProductEntity {productEntity.Id}, {productTableEntity.Title} to Catalog ReadModel for Request {correlationId}");
}
}
catch (Exception ex)
{
_logger.LogError(new EventId(ex.HResult),
ex,
"Exception throw in ProductChanged() in BasketEntity : {message}", ex.Message);
throw new Exception($"Error in ProductChanged() in BasketEntity : {ex.Message}");
}
await Task.CompletedTask;
}
/// <summary>
/// Add single line item to shopping basket
/// </summary>
/// <param name="productId">Id of productEntity to add</param>
/// <param name="correlationToken">Tracks request - can be any value</param>
/// <param name="basketId">Id of shopping basket</param>
/// <returns>BasketItemEntity</returns>
public async Task <BasketEntity> AddItemToBasket(int productId, string correlationToken,
string basketId)
{
//* Materialized View Pattern
//* Fetch product entity data from a read-only store contained in shopping basket service.
//* ProductEntity ID is row key in underlying Azure table.
//* Returns a ProductTableEntity class
var productTableEntity = await _productRepository.GetItem(ProductPartitionKey, productId.ToString(), correlationToken);
// Fallback logic
if (productTableEntity == null)
{
// Fallback:
// If product not available from local read store, fetch it from catalog service by
// making direct HTTP call to Catalog Service.
var product = await _restClient.GetAsync <ProductEntity>(ServiceEnum.Catalog, $"api/Catalog/Music/{productId}", correlationToken);
if (product == null)
{
throw new Exception(
$"Cannot add item to shopping basket: ProductEntity #{productId} does not exist for Request {correlationToken}. Have you created the ProductEntity Read Model for the Shopping BasketEntity microservice?");
}
// Transform product into an entity class for table storage
productTableEntity = new ProductTableEntity
{
// parition key is constant
PartitionKey = ProductPartitionKey,
// row key is productId
RowKey = product.Data.Id.ToString(),
Title = product.Data.Title,
Id = product.Data.Id,
GenreName = product.Data.GenreName,
ArtistName = product.Data.ArtistName,
Price = product.Data.Price.ToString()
};
// Add product entity tolocal read store, implementing a cache-aside pattern
await _productRepository.Insert(productTableEntity, correlationToken);
_logger.LogInformation(
$"Added productEntity information for item {productId} for Request {correlationToken} to the read model.");
}
BasketEntity basket = null;
// Does basketID exist?
if (basketId == "-1")
{
basketId = SnowflakeIdGenerator.GenerateId(SnowflakeEnum.Basket);
}
else
{
basket = await _distributedCacheRepository.GetBasketAsync(basketId, correlationToken, _telemetryClient);
}
// Get basket from cache
if (basket == null)
{
// BasketEntity is null, add new single item to it
basket = new BasketEntity
{
BuyerId = "2",
BasketId = basketId,
CorrelationToken = correlationToken,
Items =
{
new BasketItemEntity
{
CorrelationToken = correlationToken,
//DateCreated = DateTime.Now,
Title = productTableEntity.Title,
UnitPrice = productTableEntity.Price.ToString(),
Artist = productTableEntity.ArtistName,
Genre = productTableEntity.GenreName,
Quantity = 1,
ProductId = productId,
}
}
};
basket = await _distributedCacheRepository.UpdateBasketAsync(basket, correlationToken, _telemetryClient);
_logger.LogInformation($"Created new shopping basket {basketId} and added productEntity {productTableEntity.Title} for Request {correlationToken} ");
}
else
{
// BasketEntity is not null
// Determine if the same productEntity has already been added to the basket
var itemInBasket = basket.Items.FirstOrDefault(x => x.ProductId == Int32.Parse(productTableEntity.RowKey));
if (itemInBasket == null)
{
// ProductEntity does not exist in basket, add it
basket.Items.Add(new BasketItemEntity()
{
CorrelationToken = correlationToken,
//DateCreated = DateTime.Now,
Title = productTableEntity.Title,
UnitPrice = productTableEntity.Price.ToString(),
Artist = productTableEntity.ArtistName,
Genre = productTableEntity.GenreName,
Quantity = 1,
ProductId = Int32.Parse(productTableEntity.RowKey)
});
_logger.LogInformation($"Added productEntity Id {productId} to shopping basket {basketId} for request {correlationToken}");
}
else
{
// Idempotency write-check
// Ensure that update with same correlation token does not already exist.
// This could happen if we've already committed the write, but have gotten caught-up in retry logic.
if (itemInBasket.CorrelationToken != null && itemInBasket.CorrelationToken == correlationToken)
{
_logger.LogWarning($"ProductEntity Id {productId} already added to shopping basket {basketId} for Request {correlationToken}");
return(basket);
}
// ProductEntity already exists in basket. Increment its count.
basket.Items.FirstOrDefault(x => x.ProductId == Int32.Parse(productTableEntity.RowKey)).Quantity++;
_logger.LogInformation($"Added productEntity Id {productId} to existing shopping basket {basketId} for request {correlationToken}");
}
basket = await _distributedCacheRepository.UpdateBasketAsync(basket, correlationToken, _telemetryClient);
}
return(basket);
}
