From 74424edc8956fef5a31b3bef239e42789a158f4f Mon Sep 17 00:00:00 2001
From: Ske <voltasalt@gmail.com>
Date: Mon, 8 Feb 2021 19:53:06 +0100
Subject: [PATCH] Refactor rate limit parser, fix locale also

---
 .../Rest/Ratelimit/DiscordRateLimitPolicy.cs  |   2 +-
 Myriad/Rest/Ratelimit/RatelimitHeaders.cs     | 108 ++++++++++++------
 2 files changed, 72 insertions(+), 38 deletions(-)

diff --git a/Myriad/Rest/Ratelimit/DiscordRateLimitPolicy.cs b/Myriad/Rest/Ratelimit/DiscordRateLimitPolicy.cs
index 9c9e2d00..0ec340e1 100644
--- a/Myriad/Rest/Ratelimit/DiscordRateLimitPolicy.cs
+++ b/Myriad/Rest/Ratelimit/DiscordRateLimitPolicy.cs
@@ -37,7 +37,7 @@ namespace Myriad.Rest.Ratelimit
             var response = await action(context, ct).ConfigureAwait(continueOnCapturedContext);
 
             // Update rate limit state with headers
-            var headers = new RatelimitHeaders(response);
+            var headers = RatelimitHeaders.Parse(response);
             _ratelimiter.HandleResponse(headers, endpoint, major);
 
             return response;
diff --git a/Myriad/Rest/Ratelimit/RatelimitHeaders.cs b/Myriad/Rest/Ratelimit/RatelimitHeaders.cs
index 5387a10a..581b360e 100644
--- a/Myriad/Rest/Ratelimit/RatelimitHeaders.cs
+++ b/Myriad/Rest/Ratelimit/RatelimitHeaders.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Globalization;
 using System.Linq;
 using System.Net.Http;
 
@@ -6,46 +7,79 @@ namespace Myriad.Rest.Ratelimit
 {
     public record RatelimitHeaders
     {
-        public RatelimitHeaders() { }
+        private const string LimitHeader = "X-RateLimit-Limit";
+        private const string RemainingHeader = "X-RateLimit-Remaining";
+        private const string ResetHeader = "X-RateLimit-Reset";
+        private const string ResetAfterHeader = "X-RateLimit-Reset-After";
+        private const string BucketHeader = "X-RateLimit-Bucket";
+        private const string GlobalHeader = "X-RateLimit-Global";
+        
+        public bool Global { get; private set; }
+        public int? Limit { get; private set; }
+        public int? Remaining { get; private set; }
+        public DateTimeOffset? Reset { get; private set; }
+        public TimeSpan? ResetAfter { get; private set; }
+        public string? Bucket { get; private set; }
 
-        public RatelimitHeaders(HttpResponseMessage response)
-        {
-            ServerDate = response.Headers.Date;
-
-            if (response.Headers.TryGetValues("X-RateLimit-Limit", out var limit))
-                if (int.TryParse(limit.First(), out var limitNum))
-                    Limit = limitNum;
-
-            if (response.Headers.TryGetValues("X-RateLimit-Remaining", out var remaining))
-                if (int.TryParse(remaining!.First(), out var remainingNum))
-                    Remaining = remainingNum;
-
-            if (response.Headers.TryGetValues("X-RateLimit-Reset", out var reset))
-                if (double.TryParse(reset!.First(), out var resetNum))
-                    Reset = DateTimeOffset.FromUnixTimeMilliseconds((long) (resetNum * 1000));
-
-            if (response.Headers.TryGetValues("X-RateLimit-Reset-After", out var resetAfter))
-                if (double.TryParse(resetAfter!.First(), out var resetAfterNum))
-                    ResetAfter = TimeSpan.FromSeconds(resetAfterNum);
-
-            if (response.Headers.TryGetValues("X-RateLimit-Bucket", out var bucket))
-                Bucket = bucket.First();
-
-            if (response.Headers.TryGetValues("X-RateLimit-Global", out var global))
-                if (bool.TryParse(global!.First(), out var globalBool))
-                    Global = globalBool;
-        }
-
-        public bool Global { get; init; }
-        public int? Limit { get; init; }
-        public int? Remaining { get; init; }
-        public DateTimeOffset? Reset { get; init; }
-        public TimeSpan? ResetAfter { get; init; }
-        public string? Bucket { get; init; }
-
-        public DateTimeOffset? ServerDate { get; init; }
+        public DateTimeOffset? ServerDate { get; private set; }
 
         public bool HasRatelimitInfo =>
             Limit != null && Remaining != null && Reset != null && ResetAfter != null && Bucket != null;
+        
+        public RatelimitHeaders() { }
+
+        public static RatelimitHeaders Parse(HttpResponseMessage response)
+        {
+            var headers = new RatelimitHeaders
+            {
+                ServerDate = response.Headers.Date,
+                Limit = TryGetInt(response, LimitHeader),
+                Remaining = TryGetInt(response, RemainingHeader),
+                Bucket = TryGetHeader(response, BucketHeader)
+            };
+
+
+            var resetTimestamp = TryGetDouble(response, ResetHeader);
+            if (resetTimestamp != null)
+                headers.Reset = DateTimeOffset.FromUnixTimeMilliseconds((long) (resetTimestamp.Value * 1000));
+
+            var resetAfterSeconds = TryGetDouble(response, ResetAfterHeader);
+            if (resetAfterSeconds != null)
+                headers.ResetAfter = TimeSpan.FromSeconds(resetAfterSeconds.Value);
+            
+            var global = TryGetHeader(response, GlobalHeader);
+            if (global != null && bool.TryParse(global, out var globalBool))
+                headers.Global = globalBool;
+
+            return headers;
+        }
+
+        private static string? TryGetHeader(HttpResponseMessage response, string headerName)
+        {
+            if (!response.Headers.TryGetValues(headerName, out var values))
+                return null;
+            
+            return values.FirstOrDefault();
+        }
+
+        private static int? TryGetInt(HttpResponseMessage response, string headerName)
+        {
+            var valueString = TryGetHeader(response, headerName);
+            
+            if (!int.TryParse(valueString, NumberStyles.Integer, CultureInfo.InvariantCulture, out var value))
+                return null;
+            
+            return value;
+        }
+
+        private static double? TryGetDouble(HttpResponseMessage response, string headerName)
+        {
+            var valueString = TryGetHeader(response, headerName);
+            
+            if (!double.TryParse(valueString, NumberStyles.Float, CultureInfo.InvariantCulture, out var value))
+                return null;
+            
+            return value;
+        }
     }
 }
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