Best Practices

1. Introduction

Here you’ll find a list of recommendations that you should follow when modeling an application using OMNIA. It’s a group of best practices based on our experience collected from application development.

2. Best Practices

Descriptive naming

Use meaningful names for modeled artifacts. The name should tell you why it exists and what it does.

Use ETag when consuming the API

OMNIA Web API uses Optimistic Concurrency handling. To take advantage of if it, you should handle the ETag HTTP Header. Read here to know more: Perform conditional operations using the Web API.

Filter behaviour execution to the desired Action

Behaviours can be executed in the sequence of multiple actions. For example, an After Save can be triggered by a Create, Update or Delete. If you want to only execute the code in a given action you should apply a condition at the beginning of the behaviour.

Example to only execute the code if the operation is Create or Update:

    if (_Context.Operation.Action != Action.EntityCreate &&
        _Context.Operation.Action != Action.EntityUpdate)
    return await Task.FromResult(AfterSaveMessage.Empty);
    
    (...)

Integration: idempotent requests

Networks are unreliable, so when integrating multiple systems, it’s a best practice to ensure that the requests are idempotent. A request is idempotent if it can be called multiple times without producing additional side-effects after the first call.

To know more about idempotency:

• https://stripe.com/en-pt/blog/idempotency
• https://docs.microsoft.com/en-us/azure/architecture/microservices/design/api-design#idempotent-operations

Application Behaviours security

The authorization to execute a given application behaviour should be implemented in the Application Behaviour. Information like the current Role or Username can be accessed from the Context.

Round Calculated decimal attributes

Decimal attributes that are calculated on C# behaviours should be rounded to match the number of decimal cases defined on UI.

    this.Average = Decimal.Round(this.Amount / this.Quantity, 2);

C# - Use async/await when is possible

When working with c# Tasks using “.GetAwaiter().GetResult()”, “.Result” or “.Wait()” to get the result can cause deadlocks or thread pool starvation. So, it’s recommended to use async/await all way down.

In cases like Initialize behaviours or Action/Change behaviours, you can’t use async/await. In these cases, you should extract async methods to Code Dependencies and use “GetAwaiter().GetResult()” just once to wait for that Code Dependency.