Added some useful things

src/AspNetCoreRateLimit/Core/RateLimitProcessor.cs

@@ -129,8 +129,12 @@ protected virtual List<RateLimitRule> GetMatchingRules(ClientRequestIdentity ide
 
                 foreach (var generalLimit in generalLimits)
                 {
-                    // add general rule if no specific rule is declared for the specified period
-                    if (!limits.Exists(l => l.Period == generalLimit.Period))
+
+                    if (// add general rule if no specific rule is declared when DiscardEndpointGeneralRulesWhenExistsIPOrClienIdRule is enabled
+                        (_options.DiscardEndpointGeneralRulesWhenExistsIPOrClienIdRule && !limits.Any()) 
+                        ||
+                        // add general rule if no specific rule is declared for the specified period when DiscardEndpointGeneralRulesWhenExistsIPOrClienIdRule is disabled
+                        (!_options.DiscardEndpointGeneralRulesWhenExistsIPOrClienIdRule && !limits.Exists(l => l.Period == generalLimit.Period)))
                     {
                         limits.Add(generalLimit);
                     }

src/AspNetCoreRateLimit/Middleware/RateLimitMiddleware.cs

@@ -183,7 +183,12 @@ public virtual Task ReturnQuotaExceededResponse(HttpContext httpContext, RateLim
             {
                 httpContext.Response.Headers["Retry-After"] = retryAfter;
             }
-
+            if (rule.Limit == 0 && _options.HttpStatusCodeForLimitZeroRequests.HasValue)
+            {
+                httpContext.Response.StatusCode = _options.HttpStatusCodeForLimitZeroRequests.Value;
+                httpContext.Response.ContentType = "text/plain";
+                return httpContext.Response.WriteAsync("");
+            }
             httpContext.Response.StatusCode = _options.QuotaExceededResponse?.StatusCode ?? _options.HttpStatusCode;
             httpContext.Response.ContentType = _options.QuotaExceededResponse?.ContentType ?? "text/plain";
 

src/AspNetCoreRateLimit/Models/RateLimitOptions.cs

@@ -30,6 +30,11 @@ public class RateLimitOptions
         /// </summary>
         public int HttpStatusCode { get; set; } = 429;
 
+        /// <summary>
+        /// Gets or sets the HTTP Status code returned when rate limiting occurs, by default value is HttpStatusCode value.
+        /// </summary>
+        public int? HttpStatusCodeForLimitZeroRequests { get; set; }
+
         /// <summary>
         /// Gets or sets a value that will be used as a formatter for the QuotaExceeded response message.
         /// If none specified the default will be: 
@@ -57,6 +62,12 @@ public class RateLimitOptions
         /// </summary>
         public bool EnableEndpointRateLimiting { get; set; }
 
+        /// <summary>
+        /// Defines if general rules for an endpoint should be discarded if an ip o client id rule is defined for the same endpoint.
+        /// By default they are only discarded if there is any rule for the same period.
+        /// </summary>
+        public bool DiscardEndpointGeneralRulesWhenExistsIPOrClienIdRule { get; set; }
+
         /// <summary>
         /// Disables X-Rate-Limit and Retry-After headers
         /// </summary>

src/AspNetCoreRateLimit/Net/IPAddressRange.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Net;
 using System.Text.RegularExpressions;
@@ -21,10 +22,13 @@ public class IpAddressRange
 
         public IPAddress End { get; set; }
 
+        public List<IPAddress> IPList { get; set; }
+
         public IpAddressRange()
         {
             Begin = new IPAddress(0L);
             End = new IPAddress(0L);
+            IPList = new List<IPAddress>();
         }
 
         public IpAddressRange(string ipRangeString)
@@ -73,14 +77,31 @@ public IpAddressRange(string ipRangeString)
                 return;
             }
 
+            // Pattern 5. List of ips: "169.258.0.0,169.258.0.255"
+            var m5 = Regex.Match(ipRangeString, @"^([\da-f\.:]+)(,[\da-f\.:]+)*$", RegexOptions.IgnoreCase);
+            if (m5.Success)
+            {
+                IPList = new List<IPAddress>();
+                IPList.AddRange(ipRangeString.Split(',').Select(ipString=> IPAddress.Parse(ipString)));
+                return;
+            }
+
             throw new FormatException("Unknown IP range string.");
         }
 
         public bool Contains(IPAddress ipaddress)
         {
-            if (ipaddress.AddressFamily != Begin.AddressFamily) return false;
-            var adrBytes = ipaddress.GetAddressBytes();
-            return Bits.GE(Begin.GetAddressBytes(), adrBytes) && Bits.LE(End.GetAddressBytes(), adrBytes);
+            if (IPList != null)
+            {
+                var adrBytes = ipaddress.GetAddressBytes();
+                return IPList.Any(e => ipaddress.AddressFamily == e.AddressFamily && Bits.EQ(e.GetAddressBytes(), adrBytes));
+            }
+            else
+            {
+                if (Begin == null || ipaddress.AddressFamily != Begin.AddressFamily) return false;
+                var adrBytes = ipaddress.GetAddressBytes();
+                return Bits.GE(Begin.GetAddressBytes(), adrBytes) && Bits.LE(End.GetAddressBytes(), adrBytes);
+            }
         }
     }
 
@@ -108,6 +129,13 @@ internal static bool GE(byte[] A, byte[] B)
                 .FirstOrDefault() >= 0;
         }
 
+        internal static bool EQ(byte[] A, byte[] B)
+        {
+            return A.Zip(B, (a, b) => a == b ? 0 : 1)
+                .SkipWhile(c => c == 0)
+                .FirstOrDefault() == 0;
+        }
+
         internal static bool LE(byte[] A, byte[] B)
         {
             return A.Zip(B, (a, b) => a == b ? 0 : a < b ? 1 : -1)

src/AspNetCoreRateLimit/Store/MemoryCache/MemoryCacheRateLimitStore.cs

@@ -45,6 +45,10 @@ public Task SetAsync(string id, T entry, TimeSpan? expirationTime = null, Cancel
 
             if (expirationTime.HasValue)
             {
+                if (expirationTime.Value.TotalMilliseconds == 0)
+                {
+                    return Task.CompletedTask;
+                }
                 options.SetAbsoluteExpiration(expirationTime.Value);
             }