AutreMachine.Common

A collection of several tools useful when creating Blazor projects.

ServiceResponse

When calling functions, there is always a question lurking : if my result is null, is it normal or is it because there was a problem in the function ?

How can I have the result of the function and an indicator on if it worked well (and eventually a well designed error message) ?

ServiceReponse is a generic class that can pass a result with a Success bool (a bool indicating if the result is correct) and a Message string (to indicate the source of the problem in case the call is unsuccessful).

The idea came from Go, where exception does not exist ; everything is carried through errors passed with function calls.

Why not do the same in C# ? This notion is very elegant, and gets rid of lot of try/catch not always necessary.

One of the benefits : you can pass a meaningful message from the Business Logic layer and display it to the user.

The class is basically structured this way :

public class ServiceResponse<T>
{
    [JsonPropertyName("succeeded")]
    public bool Succeeded { get; set; }
    [JsonPropertyName("message")]
    public string Message { get; set; } = string.Empty;

    [JsonPropertyName("content")]
    public T? Content { get; set; } = default(T);
...

Note : Content holds the result, and can be null (in case of a Ko response).

There are 2 helper methods : Ok and Ko that pass the Success state and the result.

How can we use it ?

Quite simply, functions will return a ServiceResponse instead of only T class. And when the caller gets the response, it will test the Succeeded field to test the success.

For instance :

public ServiceResponse<string> GetLastName(string firstName)
{
    if (firstName == "Joe")
        return ServiceResponse<string>.Ok("Blogo"); // Pass the result to the Ok return function

    return ServiceResponse<string>.Ko($"Sorry, could not find the last name for '{firstName}... did you mean 'Joe' ?");

}

You can find more samples here : AutreMachine.Common samples

APICaller

(to be completed)

PaginatedList

Provides a pagniated list, from a IQueryable data source(ideally a DBSet from a DBContext). It is very useful to display list of items on Razor pages. For instance you could use it as following :

 IOrderedQueryable<Message>? messages = null;
 var messagesQuery = repository.GetAllQuery().Where(x => x.UserId == userId);

messages = messagesQuery.OrderByDescending(x => x.DateCreated);

var results = await PaginatedList<Message>.CreateAsync(messages, pageNumber ?? 1, pageSize);
...