validation

lib/Logitar.Identity.Core/Roles/Role.cs

@@ -129,14 +129,17 @@ public void RemoveCustomAttribute(string key)
   /// <param name="value">The value of the custom attribute.</param>
   public void SetCustomAttribute(string key, string value)
   {
-    if (string.IsNullOrWhiteSpace(key))
+    if (string.IsNullOrWhiteSpace(value))
     {
       RemoveCustomAttribute(key);
     }
 
     key = key.Trim();
     value = value.Trim();
-    // TODO(fpion): validate key
+    if (!key.IsIdentifier())
+    {
+      throw new ArgumentException("The value must be an identifier.", nameof(key));
+    }
 
     if (!_customAttributes.TryGetValue(key, out string? existingValue) || existingValue != value)
     {

lib/Logitar.Identity.Core/ValidationExtensions.cs

@@ -46,6 +46,17 @@ public static IRuleBuilderOptions<T, string> DisplayName<T>(this IRuleBuilder<T,
     return ruleBuilder.NotEmpty().MaximumLength(Core.DisplayName.MaximumLength);
   }
 
+  /// <summary>
+  /// Returns a value indicating whether or not the specified value is an identifier.
+  /// An identifier only contains letters, digits and underscores (_) and cannot start with a digit.
+  /// </summary>
+  /// <param name="value">The input string.</param>
+  /// <returns>True if the value is an identifier, or false otherwise.</returns>
+  public static bool IsIdentifier(this string value)
+  {
+    return !string.IsNullOrEmpty(value) && !char.IsDigit(value.First()) && value.All(c => char.IsLetterOrDigit(c) || c == '_');
+  }
+
   /// <summary>
   /// Defines a 'unique name' validator on the current rule builder.
   /// Validation will fail if the property is null, an empty string, only white-space, or its length exceeds the maximum length.

lib/Logitar.Identity.Core/Validators/AllowedCharactersValidator.cs

@@ -7,7 +7,7 @@ namespace Logitar.Identity.Core.Validators;
 /// The validator used to enforce a strict list of characters.
 /// </summary>
 /// <typeparam name="T">The type of the object being validated.</typeparam>
-internal class AllowedCharactersValidator<T> : IPropertyValidator<T, string>
+public class AllowedCharactersValidator<T> : IPropertyValidator<T, string>
 {
   /// <summary>
   /// Gets the allowed characters.

lib/Logitar.Identity.Core/Validators/IdentifierValidator.cs

@@ -0,0 +1,37 @@
+using FluentValidation;
+using FluentValidation.Validators;
+
+namespace Logitar.Identity.Core.Validators;
+
+/// <summary>
+/// The validator used to enforce that a string is an identifier.
+/// </summary>
+/// <typeparam name="T">The type of the object being validated.</typeparam>
+public class IdentifierValidator<T> : IPropertyValidator<T, string>
+{
+  /// <summary>
+  /// Gets the name of the validator.
+  /// </summary>
+  public string Name { get; } = "IdentifierValidator";
+
+  /// <summary>
+  /// Returns the default error message template for this validator, when not overridden.
+  /// </summary>
+  /// <param name="errorCode">The error code.</param>
+  /// <returns>The default error message template.</returns>
+  public string GetDefaultMessageTemplate(string errorCode)
+  {
+    return "'{PropertyName}' may only contain letters, digits and underscores (_), and must not start with a digit.";
+  }
+
+  /// <summary>
+  /// Validates a specific property value.
+  /// </summary>
+  /// <param name="context">The validation context.</param>
+  /// <param name="value">The value to validate.</param>
+  /// <returns>True if the value is valid, or false otherwise.</returns>
+  public bool IsValid(ValidationContext<T> context, string value)
+  {
+    return string.IsNullOrEmpty(value) || (!char.IsDigit(value.First()) && value.All(c => char.IsLetterOrDigit(c) || c == '_'));
+  }
+}