README.md

OrderCloud.Integrations.Tax.Avalara

This project brings easy tax calculation to your ecommerce app using the Avalara API. It is published as a nuget code library and conforms to standard tax interfaces published in the base library OrderCloud.Catalyst.

Basics and Installation

1. If you haven't, please read How to Calculate Tax with OrderCloud. In short, webhooks from the platform make requests to solution-custom API routes that contain tax calculation logic.
2. This library can be installed in the context of a .NET API project that responds to those webhooks. If you already have a .NET API project, great. If not, you can follow this guide. After you have published your API, you will need to configure OrderCloud to point its Integration Event webhooks at your API.
3. In your .NET project, add the OrderCloud.Integrations.Tax.Avalara nuget package with either the Visual Studio UI or the dotnet CLI.

dotnet add package OrderCloud.Integrations.Tax.Avalara

Authentication and Injection

You will need these configuration data points to authneticate to the Avalara API - BaseUrl, AccountID, LicenseKey, and CompanyCode. Create an account with avalara and get these from the admin portal.

var avalaraService = new AvalaraService(new AvalaraConfig()
{
	BaseUrl = "https://sandbox-rest.avatax.com/api/v2",
	LicenseKey = "...",
	AccountID = "...",
	CompanyCode = "...",
});

For efficient use of compute resources and clean code, create 1 AvalaraService object and make it available throughout your project using inversion of control dependency injection.

services.AddSingleton<ITaxCalculator>(avalaraService);
services.AddSingleton<ITaxCodeProvider>(avalaraService);

Notice that the interfaces being used to register avalaraService are not specific to Avalara. They are general to the domain of tax and come from the upstream OrderCloud.Catalyst package.

Usage

Create routes that respond to the OrderCloud platform's Integration Event webhooks. Inject the tax interfaces like ITaxCalculator and use them within the logic of the route. It is not recommended to rely directly on AvalaraService anywhere. The layer of abstraction that ITaxCalculator provides decouples your code from Avalara as a specific provider and hides some internal complexity of tax calculation.

public class CheckoutIntegrationEventController : CatalystController
{
	private readonly ITaxCalculator _taxCalculator;

	public CheckoutIntegrationEventController(ITaxCalculator taxCalculator)
	{
		// Inject interface. Implementation will depend on how services were registered, AvalaraService in this case.
		_taxCalculator = taxCalculator; 
	}

	....

	[HttpPost, Route("ordercalculate")] // route and method specified by OrderCloud platform
	[OrderCloudWebhookAuth] // Security feature to verifiy request came from Ordercloud.
	public async Task<OrderCalculateResponse> CalculateOrder([FromBody] OrderCalculatePayload<CheckoutConfig> payload)
	{
		// custom logic and mapping 

		var summary = new OrderSummaryForTax() { ... }
		OrderTaxCalculation taxCalculation = await _taxCalculator.CalculateEstimateAsync(summary);
		response.TaxTotal = calculation.TotalTax; // Populate Total Tax field on the Order

		...
	}

	[HttpPost, Route("ordersubmit")] // route and method specified by OrderCloud platform
	[OrderCloudWebhookAuth] // Security feature to verifiy request came from Ordercloud.
	public async Task<OrderSubmitResponse> HandleOrderSubmit([FromBody] OrderCalculatePayload<CheckoutConfig> payload)
	{
		// custom logic and mapping 

		var summary = new OrderSummaryForTax() { ... }
		await _taxCalculator.CommitTransactionAsync(summary);

		...
	}
}

This library also supports more complex cases that require mulitple tax accounts with different credentials. For example, in a franchise business model where each location is independent but all sell on one ecommerce solution. In that case, still inject one instance of AvalaraService exactly as above. You can provide empty strings for the fields. However, when you call methods on the interfaces, provide the optional configOverride parameter.

AvalaraConfig configOverride = await FetchTaxAccountCredentials(supplierID);
var summary = new OrderSummaryForTax() { ... }
OrderTaxCalculation taxCalculation = await _taxCalculator.CalculateEstimateAsync(summary, configOverride);