Add optional validation rule

ChaosBot/WebServer/Services/ValidationService.cs

@@ -29,6 +29,7 @@ namespace ChaosBot.WebServer.Services
 
                     ValidationResult result = ruleType switch
                     {
+                        "optional" => CheckOptional(key, value),
                         "required" => CheckRequired(key, value),
                         "type" => CheckType(key, value, ruleParts),
                         "min" => CheckMin(key, value, ruleParts),
@@ -36,6 +37,9 @@ namespace ChaosBot.WebServer.Services
                         _ => new ValidationResult.Unknown()
                     };
 
+                    if (result.DoesForceSuccess())
+                        break;
+
                     if (result.GetError() != null)
                     {
                         errorBuilder.AppendLine($"[{result.GetKey()}] {result.GetError()}");
@@ -48,6 +52,13 @@ namespace ChaosBot.WebServer.Services
             return error.Length == 0;
         }
 
+        private ValidationResult CheckOptional(string key, dynamic value)
+        {
+            if (value == null)
+                return new ValidationResult.SuperSuccess();
+            return new ValidationResult.Success();
+        }
+
         private ValidationResult CheckRequired(string key, dynamic value)
         {
             if (value != null)
@@ -154,7 +165,15 @@ namespace ChaosBot.WebServer.Services
             _errorMessage = errorMessage;
             _key = key;
         }
-        
+
+        internal class SuperSuccess : ValidationResult
+        {
+            public override bool DoesForceSuccess()
+            {
+                return true;
+            }
+        }
+
         internal class Success : ValidationResult {}
 
         internal class Failure : ValidationResult
@@ -172,5 +191,10 @@ namespace ChaosBot.WebServer.Services
         {
             return this._key;
         }
+
+        public virtual bool DoesForceSuccess()
+        {
+            return false;
+        }
     }
 }