so optimal

DamianEdwards · DamianEdwards · commit a10c107559d3 · 2025-07-08T10:51:29.000-07:00
diff --git a/src/Servers/Kestrel/Core/src/Internal/AddressBinder.cs b/src/Servers/Kestrel/Core/src/Internal/AddressBinder.cs
@@ -154,11 +154,10 @@ bool IsLocalhost(string host, out string? prefix)
             // Check for use of .localhost TLD (Top Level Domain)
             if (host.EndsWith(".localhost", StringComparison.OrdinalIgnoreCase))
             {
-                var localhostTldIndex = host.LastIndexOf('.');
-                if (localhostTldIndex > 0)
+                if (host.LastIndexOf('.') > 0)
                 {
                     // Take all but the .localhost TLD as the prefix
-                    prefix = host[..localhostTldIndex];
+                    prefix = host[..^10]; // 10 is the length of ".localhost"
                     return true;
                 }
             }

Original file line number	Diff line number	Diff line change
`@@ -154,11 +154,10 @@ bool IsLocalhost(string host, out string? prefix)`
`154`	`154`	`// Check for use of .localhost TLD (Top Level Domain)`
`155`	`155`	`if (host.EndsWith(".localhost", StringComparison.OrdinalIgnoreCase))`
`156`	`156`	`{`
`157`		`- var localhostTldIndex = host.LastIndexOf('.');`
`158`		`- if (localhostTldIndex > 0)`
	`157`	`+ if (host.LastIndexOf('.') > 0)`
`159`	`158`	`{`
`160`	`159`	`// Take all but the .localhost TLD as the prefix`
`161`		`- prefix = host[..localhostTldIndex];`
	`160`	`+ prefix = host[..^10]; // 10 is the length of ".localhost"`
`162`	`161`	`return true;`
`163`	`162`	`}`
`164`	`163`	`}`