FluentValidation.AspNetCore.Http

A simple ASP.NET Core 7+ Minimal API integration for FluentValidation 10+.

The package leverages endpoint filters to trigger FluentValidation IValidator<T>. In case of a validation error, the filter returns a TypedResults.ValidationProblem(errors);, where the errors argument represents the collection of failures. You can customize this behavior by implementing the IFluentValidationEndpointFilterResultsFactory interface.

How to install

dotnet add package ForEvolve.FluentValidation.AspNetCore.Http

Pre-release feedz.io URL:

https://f.feedz.io/forevolve/fluentvalidation/nuget/index.json

How to use

In your Program.cs file, you must register the library:

builder.AddFluentValidationEndpointFilter();

You can then add the validation filter to an endpoint:

using FluentValidation.AspNetCore.Http;
//...
app.MapGet("/some-path", (SomeParamToValidate model) => {
    // ...
}).AddFluentValidationFilter();

You can also add the validation filter to a group instead, which applies the filter to all of the group's endpoints:

using FluentValidation.AspNetCore.Http;
//...
var root = app
    .MapGroup("/")
    .AddFluentValidationFilter()
;
// Then you can register endpoints that will get validated, like:
root.MapGet("/some-path", (SomeParamToValidate model) => {
    //...
});

You must register your validators normally. Here is an example that has nothing to do with this library and only uses FluentValidation:

// Using the assembly scanning feature
builder.Services.AddValidatorsFromAssemblyContaining<Program>();

// Manually registering a validator
builder.Services.AddScoped<IValidator<MyEntity>, MyEntityValidator>();

Settings

You can configure the FluentValidationEndpointFilterSettings class during the registration as follow:

builder.AddFluentValidationEndpointFilter(settings => {
    settings.ScanningStrategy = ScanningStrategy.ScanUntilNoValidatorFound;
});

You can also leverage ASP.NET Core Configure and PostConfigure methods as usual, like this:

builder.Services.Configure<FluentValidationEndpointFilterSettings>(options =>
{
    options.ScanningStrategy = ScanningStrategy.ScanUntilNoValidatorFound;
});

Finally, you can configure the filter in the appsettings.json file under the FluentValidationEndpointFilter key, like this:

{
  "FluentValidationEndpointFilter": {
    "ScanningStrategy": "ScanUntilNoValidatorFound"
  }
}

ScanningStrategy

The only configuration at this time is the scanning strategy that contains the following options:

1. ScanAllParams (default behavior): The filter scans all parameters. For each parameter, it tries to get an IValidator<T> instance from the ASP.NET Core container. When it finds one, the filter validates the parameter.
2. ScanUntilNoValidatorFound: The filter scans parameters until it does not find a validator for a parameter. When that happens, the validation stops.

   When using this strategy, you must first add the objects to validate, then add the services or other injected types.

Examples

You can browse the examples directory for usage examples.

Versioning

The package follows semantic versioning and uses Nerdbank.GitVersioning under the hood to automate versioning based on Git commits.