DataAnnotatedModelValidations

Data Annotated Model Validation Middleware for HotChocolate.

The purpose of this Middleware is to provide the same behavior as ASP.Net controllers, where all models would be validated according to the specified Data Annotations or the IValidatableObject implementation; in essence it's always on.

In addition, individual method arguments can be validated using annotations from System.ComponentModel.Annotations.

Nuget

Compatibility

Current Releases

HotChocolate Version	DataAnnotatedModelValidations Version	.NET Version
14.3.0 or higher	6.3.0	.NET 8, 9
14.2.0 or higher	6.2.0	.NET 8, 9
14.1.0 or higher	6.1.0	.NET 8, 9
14.0.0 or higher	6.0.0	.NET 8
13.9.0 or higher	5.2.0	.NET 6, 7, 8
13.7.0 or higher	5.1.0	.NET 6, 7, 8
13.7.0 or higher	5.0.0	.NET 6, 7, 8

Past Releases

HotChocolate Version	Last DataAnnotatedModelValidations Version	.NET Version
13.7.0 or higher	4.2.0	.NET 6, 7
12.16.0 or higher	3.0.1	.NET 7
12.4.1 or higher	2.1.4	.NET 6

📝For more information please visit https://www.nuget.org/packages/DataAnnotatedModelValidations/#versions-body-tab

Usage

Locate your GraphQL Server registration and append .AddDataAnnotationsValidator()

ex.

// Startup.cs
public void ConfigureServices(IServiceCollection services)
{
    // ...
    services
        .AddGraphQLServer()
        .AddDataAnnotationsValidator()
        .AddQueryType<Query>();
    // ...
}

Excluding a model from being validated

To exclude a certain method argument from being validated just add the IgnoreModelValidation attribute.

ex.

public class Sample
{
    [Required]
    [MinLength(3)]
    [EmailAddress]
    public string? Email { get; set; }
}

public class Query
{
    public string? GetTextIgnoreValidation([IgnoreModelValidation][MinLength(5)] string? text) => text;

    public Sample? GetSampleIgnoreValidation([IgnoreModelValidation] Sample? sample) => sample;
}

Models

In C# one may define models in a multitude of ways.

To help alleviate potential issues consider the following:

Standard Classes

public class Sample
{
    [Required]
    [MinLength(3)]
    [EmailAddress]
    public string? Email { get; set; }
}

Records with declared properties

public record Sample
{
    [Required]
    [MinLength(3)]
    [EmailAddress]
    public string? Email { get; set; }
}

Records with auto synthesized properties

The auto-property is initialized to the value of the corresponding primary constructor parameter. Attributes can be applied to the synthesized auto-property and its backing field by using property: or field: targets for attributes syntactically applied to the corresponding record parameter.

https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/proposals/csharp-9.0/records

So per the documentation and following the guideline, a solution to the challenge mentioned would be adding the property: prefix to the validation attribute.

public record Sample(
    [property:Required]
    [property:MinLength(3)]
    [property:EmailAddress]
    string? Email
);

Notes

When implementing the IValidatableObject interface HotChocolate considers the Validate as a resolver; to avoid getting schema errors said method needs to be ignored.

ex.

public class Sample : IValidatableObject
{
    [Required]
    [MinLength(3)]
    [EmailAddress]
    public string? Email { get; set; }

    [GraphQLIgnore]
    public IEnumerable<ValidationResult> Validate(ValidationContext validationContext) =>
        Email?.StartsWith("no-property-name") == true
            ? new[] { new ValidationResult("no-property-name") }
            : Enumerable.Empty<ValidationResult>();
}

Numerical sequences

If you need to support numerical sequences in your validation results, consider adding the names as FieldName:[index].

The field name will be transformed in the error path as fieldName,_index_.

{
  "errors": [
    {
      "message": "The field Count must be between 1 and 10.",
      "path": [
        "sample",
        "obj",
        "children",
        "_2_",
        "count"
      ],
      "extensions": {
        "code": "DAMV-400",
        "field": "sample",
        "type": "Mutation",
        "specifiedBy": "https://spec.graphql.org/June2018/#sec-Values-of-Correct-Type"
      }
    }
  ]
}

If you choose to omit the : character and add the names as FieldName[index] the field name and the index will be represented as one entry, fieldName_index_.

{
  "errors": [
    {
      "message": "The field Count must be between 1 and 10.",
      "path": [
        "sample",
        "obj",
        "children_2_",
        "count"
      ],
      "extensions": {
        "code": "DAMV-400",
        "field": "sample",
        "type": "Mutation",
        "specifiedBy": "https://spec.graphql.org/June2018/#sec-Values-of-Correct-Type"
      }
    }
  ]
}

Multiple members

If multiple member names are added they will be treated as distinct error messages.

Ex. validation error '"Some validation error!"' was assigned to properties hello and world:

{
  "errors": [
    {
      "message": "Some validation error!",
      "path": [
        "sample",
        "obj",
        "hello"
      ],
      "extensions": {
        "code": "DAMV-400",
        "field": "sample",
        "type": "Query",
        "specifiedBy": "https://spec.graphql.org/June2018/#sec-Values-of-Correct-Type"
      }
    },
    {
      "message": "Some validation error!",
      "path": [
        "sample",
        "obj",
        "world"
      ],
      "extensions": {
        "code": "DAMV-400",
        "field": "sample",
        "type": "Query",
        "specifiedBy": "https://spec.graphql.org/June2018/#sec-Values-of-Correct-Type"
      }
    }
  ],
  "data": {
    "sample": null
  }
}

Property nesting

If there is a need to express a nested relationship of a property and it's parent, consider adding the names separated by a colon as ParentName:FieldName:[index]

Similar Projects

• https://github.com/VarunSaiTeja/Graph.ArgumentValidator