// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System.ComponentModel.DataAnnotations;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.Linq;
using Microsoft.AspNetCore.Components.Forms;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Localization;
using Microsoft.Extensions.Options;
using Microsoft.Extensions.Validation;
namespace Microsoft.AspNetCore.Components.Endpoints.Forms;
internal sealed class DataAnnotationsClientValidationProvider : ClientValidationProvider
{
private readonly ClientValidationCache _clientValidationCache;
private readonly DataAnnotationsLocalizer _localizer;
private readonly bool _clientValidationDisabled;
[UnconditionalSuppressMessage("Trimming", "IL2066", Justification = "Preserves ValidationOptions's parameterless constructor used by Microsoft.Extensions.Options to materialize IOptions<ValidationOptions>.")]
[DynamicDependency(DynamicallyAccessedMemberTypes.PublicParameterlessConstructor, typeof(ValidationOptions))]
public DataAnnotationsClientValidationProvider(
ClientValidationCache clientValidationCache,
IOptions<ValidationOptions> validationOptions,
IOptions<RazorComponentsServiceOptions> razorComponentsOptions,
IServiceProvider serviceProvider)
{
_clientValidationCache = clientValidationCache;
_clientValidationDisabled = razorComponentsOptions.Value.DisableClientValidation;
var stringLocalizerFactory = serviceProvider.GetService<IStringLocalizerFactory>();
_localizer = new DataAnnotationsLocalizer(validationOptions.Value, stringLocalizerFactory);
}
public override RenderFragment? RenderClientValidationRules(EditContext editContext, IReadOnlyDictionary<FieldIdentifier, string> renderedFields)
{
if (_clientValidationDisabled)
{
return null;
}
var json = SerializeClientValidationData(editContext, renderedFields);
if (json is null)
{
return null;
}
return builder =>
{
builder.OpenElement(0, "blazor-client-validation-data");
// The rules are carried in the data-rules attribute, not as element content, so the
// element renders nothing at all in the DOM.
builder.AddAttribute(1, "data-rules", json);
builder.CloseElement();
};
}
// Returns JSON string with the client-validation payload for the rendered fields directly, or null when
// there is nothing to emit.
internal string? SerializeClientValidationData(EditContext editContext, IReadOnlyDictionary<FieldIdentifier, string> renderedFields)
{
ArgumentNullException.ThrowIfNull(editContext);
if (renderedFields.Count == 0)
{
return null;
}
var writer = new ClientValidationDataWriter();
var validatableFields = _clientValidationCache.GetValidatableFieldMetadata(renderedFields, editContext.Model);
var useStringLocalizer = _clientValidationCache.HasValidatableTypeInfo(editContext.Model.GetType());
foreach (var (renderedName, fieldMetadata) in validatableFields)
{
WriteFieldRules(writer, renderedName, fieldMetadata, useStringLocalizer);
}
return writer.Complete();
}
private void WriteFieldRules(ClientValidationDataWriter writer, string renderedName, ClientValidationFieldMetadata fieldMetadata, bool useStringLocalizer)
{
var displayName = _localizer.ResolveDisplayName(fieldMetadata, useStringLocalizer);
writer.BeginField(renderedName);
foreach (var attribute in fieldMetadata.ValidationAttributes)
{
var errorMessage = _localizer.ResolveAttributeErrorMessage(fieldMetadata.PropertyName, displayName, fieldMetadata.DeclaringType, attribute, useStringLocalizer)
?? string.Empty;
if (TryWriteBuiltInRule(writer, attribute, errorMessage))
{
continue;
}
if (attribute is IClientValidationRuleProvider ruleProvider)
{
foreach (var customRule in ruleProvider.GetClientValidationRules())
{
writer.BeginRule(customRule.Name, errorMessage);
if (customRule.Parameters is { Count: > 0 } parameters)
{
foreach (var kvp in parameters)
{
writer.Param(kvp.Key, kvp.Value);
}
}
writer.EndRule();
}
}
}
writer.EndField();
}
// Writes the rule for each built-in ValidationAttribute directly to JSON and returns true, or
// returns false when the attribute is not a built-in (custom adapters handle those elsewhere).
private static bool TryWriteBuiltInRule(ClientValidationDataWriter writer, ValidationAttribute validationAttribute, string errorMessage)
{
switch (validationAttribute)
{
case RequiredAttribute:
writer.BeginRule("required"u8, errorMessage);
writer.EndRule();
return true;
case StringLengthAttribute sla:
writer.BeginRule("length"u8, errorMessage);
if (sla.MaximumLength != int.MaxValue)
{
writer.Param("max"u8, sla.MaximumLength);
}
if (sla.MinimumLength != 0)
{
writer.Param("min"u8, sla.MinimumLength);
}
writer.EndRule();
return true;
case MaxLengthAttribute maxla:
writer.BeginRule("maxlength"u8, errorMessage);
writer.Param("max"u8, maxla.Length);
writer.EndRule();
return true;
case MinLengthAttribute minla:
writer.BeginRule("minlength"u8, errorMessage);
writer.Param("min"u8, minla.Length);
writer.EndRule();
return true;
// The JS range validator is numeric-only (uses Number()); skip non-numeric operands.
case RangeAttribute ra when IsNumericRangeOperand(ra.OperandType):
// Triggers RangeAttribute.SetupConversion() to convert string Min/Max to OperandType.
ra.IsValid(3);
writer.BeginRule("range"u8, errorMessage);
writer.Param("min"u8, Convert.ToString(ra.Minimum, CultureInfo.InvariantCulture)!);
writer.Param("max"u8, Convert.ToString(ra.Maximum, CultureInfo.InvariantCulture)!);
writer.EndRule();
return true;
case RegularExpressionAttribute rea:
writer.BeginRule("regex"u8, errorMessage);
writer.Param("pattern"u8, rea.Pattern);
writer.EndRule();
return true;
case CompareAttribute ca:
writer.BeginRule("equalto"u8, errorMessage);
// "*." prefix tells the JS equalto validator to resolve the other field relative to
// the current field's name prefix.
writer.Param("other"u8, "*." + ca.OtherProperty);
writer.EndRule();
return true;
case EmailAddressAttribute:
writer.BeginRule("email"u8, errorMessage);
writer.EndRule();
return true;
case UrlAttribute:
writer.BeginRule("url"u8, errorMessage);
writer.EndRule();
return true;
case PhoneAttribute:
writer.BeginRule("phone"u8, errorMessage);
writer.EndRule();
return true;
case CreditCardAttribute:
writer.BeginRule("creditcard"u8, errorMessage);
writer.EndRule();
return true;
case FileExtensionsAttribute fea:
writer.BeginRule("fileextensions"u8, errorMessage);
writer.Param("extensions"u8, GetNormalizedExtensions(fea));
writer.EndRule();
return true;
default:
return false;
}
}
private static string GetNormalizedExtensions(FileExtensionsAttribute fea)
{
var normalizedExtensions = fea.Extensions
.Replace(" ", string.Empty)
.Replace(".", string.Empty)
.ToLowerInvariant();
return string.Join(",", normalizedExtensions.Split(',').Select(e => "." + e));
}
// RangeAttribute supports non-numeric operand types (e.g., DateTime) that the JS validator
// can't compare; only emit "range" rules for numeric operand types.
private static bool IsNumericRangeOperand(Type operandType)
=> operandType == typeof(int)
|| operandType == typeof(long)
|| operandType == typeof(short)
|| operandType == typeof(byte)
|| operandType == typeof(uint)
|| operandType == typeof(ulong)
|| operandType == typeof(ushort)
|| operandType == typeof(sbyte)
|| operandType == typeof(double)
|| operandType == typeof(float)
|| operandType == typeof(decimal);
}