token retrieval from header or qs

src/Core/IdentityServer/TokenRetrieval.cs

@@ -0,0 +1,32 @@
+using Microsoft.AspNetCore.Http;
+using System;
+using System.Linq;
+
+namespace Bit.Core.IdentityServer
+{
+    public static class TokenRetrieval
+    {
+        private static string _headerScheme = "Bearer ";
+        private static string _queuryScheme = "access_token";
+        private static string _authHeader = "Authorization";
+
+        public static Func<HttpRequest, string> FromAuthorizationHeaderOrQueryString()
+        {
+            return (request) =>
+            {
+                var authorization = request.Headers[_authHeader].FirstOrDefault();
+                if(string.IsNullOrWhiteSpace(authorization))
+                {
+                    return request.Query[_queuryScheme].FirstOrDefault();
+                }
+
+                if(authorization.StartsWith(_headerScheme, StringComparison.OrdinalIgnoreCase))
+                {
+                    return authorization.Substring(_headerScheme.Length).Trim();
+                }
+
+                return null;
+            };
+        }
+    }
+}