Coding style

use "using" and raw string when there is a lot of "

Author: ngraziano

RTSP.Tests/Authentication/AuthenticationDigestTests.cs

@@ -9,12 +9,22 @@ namespace RTSP.Tests.Authentication
     public class AuthenticationDigestTests
     {
         // MD5, no Algorithm specified
-        string authStringPLAY_MD5_noalg = "Digest username=\"user\", realm=\"SharpRTSPServer\", nonce=\"556284985\", uri=\"rtsp://192.168.26.76:8554/\", response=\"f3ce799d94cb45e14bf59e57cd41c749\"";
-        string authStringPLAY_MD5_with_alg = "Digest username=\"user\", realm=\"SharpRTSPServer\", nonce=\"556284985\", uri=\"rtsp://192.168.26.76:8554/\", response=\"f3ce799d94cb45e14bf59e57cd41c749\", algorithm=\"MD5\"";
-        string authStringPLAY_SHA256 = "Digest username=\"user\", realm=\"SharpRTSPServer\", nonce=\"729461183\", uri=\"rtsp://192.168.26.76:8554/\", response=\"9f6d99e827799b23b273aaf62f7eea84a720e25a205284a921f0d9aa14621dcc\", algorithm=\"SHA-256\"";
-        string authStringPLAY_BadAlg = "Digest username=\"user\", realm=\"SharpRTSPServer\", nonce=\"729461183\", uri=\"rtsp://192.168.26.76:8554/\", response=\"9f6d99e827799b23b273aaf62f7eea84a720e25a205284a921f0d9aa14621dcc\", algorithm=\"BADVALUE\"";
-        string realm = "SharpRTSPServer";
-        string qop = "";
+        private const string authStringPLAY_MD5_noalg = """
+            Digest username="user", realm="SharpRTSPServer", nonce="556284985", uri="rtsp://192.168.26.76:8554/", response="f3ce799d94cb45e14bf59e57cd41c749"
+            """;
+        private const string authStringPLAY_MD5_with_alg = """
+            Digest username="user", realm="SharpRTSPServer", nonce="556284985", uri="rtsp://192.168.26.76:8554/", response="f3ce799d94cb45e14bf59e57cd41c749", algorithm="MD5"
+            """;
+        private const string authStringPLAY_SHA256 = """
+            Digest username="user", realm="SharpRTSPServer", nonce="729461183", uri="rtsp://192.168.26.76:8554/", response="9f6d99e827799b23b273aaf62f7eea84a720e25a205284a921f0d9aa14621dcc", algorithm="SHA-256"
+            """;
+
+        private const string authStringPLAY_BadAlg = """
+            Digest username="user", realm="SharpRTSPServer", nonce="729461183", uri="rtsp://192.168.26.76:8554/", response="9f6d99e827799b23b273aaf62f7eea84a720e25a205284a921f0d9aa14621dcc", algorithm="BADVALUE"
+            """;
+        
+        private const string realm = "SharpRTSPServer";
+        private const string qop = "";
 
         [Test]
         public void IsValid_MD5_No_Alg_Test1()
@@ -78,7 +88,7 @@ public void GetWWWAuthenticate_MD5()
             var testObject = new AuthenticationDigest(new NetworkCredential("user", "password", realm), realm, nonce, qop, AuthenticationDigest.HashAlgorithm.MD5);
             var result = testObject.GetServerResponse();
 
-            Assert.That(result.Contains("algorithm"), Is.False); // We don't add 'algorithm=MD5' as it is not required
+            Assert.That(result, Does.Not.Contain("algorithm")); // We don't add 'algorithm=MD5' as it is not required
         }
 
         [Test]
@@ -91,7 +101,8 @@ public void GetWWWAuthenticate_SHA256()
             var testObject = new AuthenticationDigest(new NetworkCredential("user", "password", realm), realm, nonce, qop, AuthenticationDigest.HashAlgorithm.SHA256);
             var result = testObject.GetServerResponse();
 
-            Assert.That(result.Contains("algorithm") && result.Contains("SHA-256"), Is.True);
+            Assert.That(result, Does.Contain("algorithm"));
+            Assert.That(result, Does.Contain("SHA-256"));
         }
 
     }

RTSP/AuthenticationDigest.cs

@@ -51,11 +51,7 @@ public override string GetServerResponse()
         public override string GetResponse(uint nonceCounter, string uri, string method,
             byte[] entityBodyBytes)
         {
-            System.Security.Cryptography.HashAlgorithm hashAlgorithm;
-            if (_algorithm == HashAlgorithm.SHA256)
-                hashAlgorithm = SHA256.Create();
-            else /* default is MD5 */
-                hashAlgorithm = MD5.Create();
+            using var hashAlgorithm = CreateHashAlgorithm(_algorithm);
 
             string ha1 = CalculateHash(hashAlgorithm, $"{Credentials.UserName}:{_realm}:{Credentials.Password}");
             string ha2Argument = $"{method}:{uri}";
@@ -80,8 +76,6 @@ public override string GetResponse(uint nonceCounter, string uri, string method,
                 sb.AppendFormat(CultureInfo.InvariantCulture, ", response=\"{0}\", cnonce=\"{1}\", nc=\"{2:X8}\", qop=\"{3}\"", response, _cnonce, nonceCounter, _qop);
             }
 
-            hashAlgorithm.Dispose();
-
             return sb.ToString();
         }
         public override bool IsValid(RtspRequest receivedMessage)
@@ -137,16 +131,11 @@ public override bool IsValid(RtspRequest receivedMessage)
 
                 // Create the MD5 Hash using all parameters passed in the Auth Header with the 
                 // addition of the 'Password'
-                System.Security.Cryptography.HashAlgorithm hashAlgorithm;
-                if (algorithm == HashAlgorithm.SHA256)
-                    hashAlgorithm = SHA256.Create();
-                else /* Default to MD5 */
-                    hashAlgorithm = MD5.Create();
+                using var hashAlgorithm = CreateHashAlgorithm(algorithm);
 
                 string hashA1 = CalculateHash(hashAlgorithm, username + ":" + realm + ":" + Credentials.Password);
                 string hashA2 = CalculateHash(hashAlgorithm, receivedMessage.RequestTyped + ":" + uri);
                 string expectedResponse = CalculateHash(hashAlgorithm, hashA1 + ":" + nonce + ":" + hashA2);
-                hashAlgorithm.Dispose();
 
                 // Check if everything matches
                 // ToDo - extract paths from the URIs (ignoring SETUP's trackID)
@@ -158,6 +147,14 @@ public override bool IsValid(RtspRequest receivedMessage)
             return false;
         }
 
+        private static System.Security.Cryptography.HashAlgorithm CreateHashAlgorithm(HashAlgorithm algorithm) =>
+            algorithm switch
+            {
+                HashAlgorithm.SHA256 => SHA256.Create(),
+                /* default is MD5 */
+                _ => MD5.Create(),
+            };
+
         private static string CalculateHash(System.Security.Cryptography.HashAlgorithm hashAlgorithm, string input)
         {
             byte[] inputBytes = Encoding.UTF8.GetBytes(input);