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Cookbook ​

Short recipes for common steps. Each uses an input type Order and an output type OrderDto; replace them with your own flow types.

Map a record ​

csharp
public override void Execute(IMetaData metaDataInstance, IViaType inputDataInstance)
{
    var metaData = (viauser.FlowMetaData)metaDataInstance;
    var order = (Order)inputDataInstance;
    var dto = new OrderDto { Id = order.Id, Total = order.Amount + order.Tax };
    Next(metaData, dto);
}
python
def execute(metaData: FlowMetaData, inputData: Order):
    dto = OrderDto()
    dto.Id = inputData.Id
    dto.Total = inputData.Amount + inputData.Tax
    services.Next(metaData, dto)
javascript
async function execute(metaData, inputData) {
	const dto = new OrderDto();
	dto.Id = inputData.Id;
	dto.Total = inputData.Amount + inputData.Tax;
	services.Next(metaData, dto);
}

Filter records ​

Return without calling Next to drop a record.

csharp
if (order.Status != "Paid") return;
Next(metaData, order);
python
if inputData.Status != "Paid":
    return
services.Next(metaData, inputData)
javascript
if (inputData.Status !== "Paid") return;
services.Next(metaData, inputData);

Split a list into records ​

csharp
foreach (var line in order.Lines)
    Next(metaData, new OrderLineDto { OrderId = order.Id, Sku = line.Sku, Quantity = line.Quantity });
python
for line in inputData.Lines:
    dto = OrderLineDto()
    dto.OrderId = inputData.Id
    dto.Sku = line.Sku
    dto.Quantity = line.Quantity
    services.Next(metaData, dto)
javascript
for (const line of inputData.Lines) {
	const dto = new OrderLineDto();
	dto.OrderId = inputData.Id;
	dto.Sku = line.Sku;
	dto.Quantity = line.Quantity;
	services.Next(metaData, dto);
}

When the consumer works in batches, send the lines in a batch.

Read a setting ​

csharp
var threshold = Services.Settings.Get<decimal>("Orders", "ReviewThreshold");
if (order.Amount > threshold) Services.Log.Warning($"Order {order.Id} needs review", metaData, order);
python
threshold = float(services.Settings.Get("Orders", "ReviewThreshold"))
if inputData.Amount > threshold:
    services.Log.Warning(f"Order {inputData.Id} needs review")
javascript
const threshold = Number(services.Settings.Get("Orders", "ReviewThreshold"));
if (inputData.Amount > threshold) services.Log.Warning(`Order ${inputData.Id} needs review`);

Number records ​

A sequence gives unique numbers that survive restarts.

csharp
Services.Storage.Sequences.NewIfMissing("invoice");
dto.InvoiceNumber = $"INV-{Services.Storage.Sequences.Next("invoice"):D6}";
python
services.Storage.Sequences.NewIfMissing("invoice")
dto.InvoiceNumber = f"INV-{services.Storage.Sequences.Next('invoice'):06d}"
javascript
services.Storage.Sequences.NewIfMissing("invoice");
dto.InvoiceNumber = "INV-" + String(services.Storage.Sequences.Next("invoice")).padStart(6, "0");

Call an HTTP API ​

For most calls the Http client plugin is the better choice. Inside a script:

csharp
private static readonly HttpClient _http = new();

public override async Task ExecuteAsync(IMetaData metaDataInstance, IViaType inputDataInstance)
{
    var metaData = (viauser.FlowMetaData)metaDataInstance;
    var order = (Order)inputDataInstance;
    var url = Services.Settings.Get("Crm", "ApiUrl");
    var json = await _http.GetStringAsync($"{url}/customers/{order.CustomerId}", Services.CancellationToken);
    order.CustomerJson = json;
    await NextAsync(metaData, order);
}
python
import urllib.request

def execute(metaData: FlowMetaData, inputData: Order):
    url = services.Settings.Get("Crm", "ApiUrl")
    with urllib.request.urlopen(f"{url}/customers/{inputData.CustomerId}") as response:
        inputData.CustomerJson = response.read().decode("utf-8")
    services.Next(metaData, inputData)
javascript
async function execute(metaData, inputData) {
	const url = services.Settings.Get("Crm", "ApiUrl");
	const response = await fetch(`${url}/customers/${inputData.CustomerId}`);
	if (!response.ok) throw new Error(`CRM answered ${response.status}`);
	inputData.CustomerJson = await response.text();
	services.Next(metaData, inputData);
}

The C# version needs Async/Await switched on.

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