Samples for core whats new 3.0

core/whats-new/whats-new-in-30/cs/Cipher.cs

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+// <SnippetAesGcm>
+using System;
+using System.Linq;
+using System.Security.Cryptography;
+
+namespace whats_new
+{
+    public static class Cipher
+    {
+        public static void Run()
+        {
+            // key should be: pre-known, derived, or transported via another channel, such as RSA encryption
+            byte[] key = new byte[16];
+            RandomNumberGenerator.Fill(key);
+
+            byte[] nonce = new byte[12];
+            RandomNumberGenerator.Fill(nonce);
+
+            // normally this would be your data
+            byte[] dataToEncrypt = new byte[1234];
+            byte[] associatedData = new byte[333];
+            RandomNumberGenerator.Fill(dataToEncrypt);
+            RandomNumberGenerator.Fill(associatedData);
+
+            // these will be filled during the encryption
+            byte[] tag = new byte[16];
+            byte[] ciphertext = new byte[dataToEncrypt.Length];
+
+            using (AesGcm aesGcm = new AesGcm(key))
+            {
+                aesGcm.Encrypt(nonce, dataToEncrypt, ciphertext, tag, associatedData);
+            }
+
+            // tag, nonce, ciphertext, associatedData should be sent to the other part
+
+            byte[] decryptedData = new byte[ciphertext.Length];
+
+            using (AesGcm aesGcm = new AesGcm(key))
+            {
+                aesGcm.Decrypt(nonce, ciphertext, tag, decryptedData, associatedData);
+            }
+
+            // do something with the data
+            // this should always print that data is the same
+            Console.WriteLine($"AES-GCM: Decrypted data is {(dataToEncrypt.SequenceEqual(decryptedData) ? "the same as" : "different than")} original data.");
+        }
+    }
+}
+// </SnippetAesGcm>

core/whats-new/whats-new-in-30/cs/Program.cs

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+using System;
+using System.IO;
+using System.Text.Json;
+using System.Threading.Tasks;
+
+namespace whats_new
+{
+    class Program
+    {
+
+        static async Task Main(string[] args)
+        {
+            // <SnippetPrintJsonCall>
+            // Calling code
+            Console.WriteLine("Read with Utf8JsonReader");
+            PrintJson(File.ReadAllBytes("launch.json").AsSpan());
+            // </SnippetPrintJsonCall>
+
+            // <SnippetReadJsonCall>
+            // Calling code
+            Console.WriteLine("Read with JsonDocument");
+            ReadJson(File.ReadAllText("launch.json"));
+            // </SnippetReadJsonCall>
+
+            //await TLS.ConnectCloudFlare();
+
+            //Cipher.Run();
+
+        }
+
+        // <SnippetPrintJson>
+        public static void PrintJson(ReadOnlySpan<byte> dataUtf8)
+        {
+            var json = new Utf8JsonReader(dataUtf8, isFinalBlock: true, state: default);
+
+            while (json.Read())
+            {
+                JsonTokenType tokenType = json.TokenType;
+                ReadOnlySpan<byte> valueSpan = json.ValueSpan;
+                switch (tokenType)
+                {
+                    case JsonTokenType.StartObject:
+                    case JsonTokenType.EndObject:
+                        break;
+                    case JsonTokenType.StartArray:
+                    case JsonTokenType.EndArray:
+                        break;
+                    case JsonTokenType.PropertyName:
+                        break;
+                    case JsonTokenType.String:
+                        Console.WriteLine($"STRING: {json.GetString()}");
+                        break;
+                    case JsonTokenType.Number:
+                        if (!json.TryGetInt32(out int valueInteger))
+                        {
+                            throw new FormatException();
+                        }
+                        break;
+                    case JsonTokenType.True:
+                    case JsonTokenType.False:
+                        Console.WriteLine($"BOOL: {json.GetBoolean()}");
+                        break;
+                    case JsonTokenType.Null:
+                        break;
+                    default:
+                        throw new ArgumentException();
+                }
+            }
+
+            dataUtf8 = dataUtf8.Slice((int)json.BytesConsumed);
+            JsonReaderState state = json.CurrentState;
+        }
+        // </SnippetPrintJson>
+
+        // <SnippetReadJson>
+        public static void ReadJson(string jsonString)
+        {
+            using var document = JsonDocument.Parse(jsonString);
+
+            var root = document.RootElement;
+            var version = root.GetProperty("version").GetString();
+            var configurations = root.GetProperty("configurations");
+
+            Console.WriteLine($"Launch Version: {version}");
+
+            foreach (var config in configurations.EnumerateArray())
+            {
+                var name = config.GetProperty("name").GetString();
+                Console.WriteLine($"Config: {name}");
+            }
+        }
+        // </SnippetReadJson>
+    }
+}

core/whats-new/whats-new-in-30/cs/RSA.cs

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+// <SnippetRsa>
+using System;
+using System.Security.Cryptography;
+
+namespace whats_new
+{
+    public static class RSATest
+    {
+        public static void Run(string keyFile)
+        {
+            using var rsa = RSA.Create();
+
+            byte[] keyBytes = System.IO.File.ReadAllBytes(keyFile);
+            rsa.ImportRSAPrivateKey(keyBytes, out int bytesRead);
+
+            Console.WriteLine($"Read {bytesRead} bytes, {keyBytes.Length - bytesRead} extra byte(s) in file.");
+            RSAParameters rsaParameters = rsa.ExportParameters(true);
+            Console.WriteLine(BitConverter.ToString(rsaParameters.D));
+        }
+    }
+}
+// </SnippetRsa>

core/whats-new/whats-new-in-30/cs/TLS.cs

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+// <SnippetTLS>
+using System;
+using System.Net.Security;
+using System.Net.Sockets;
+using System.Threading.Tasks;
+
+namespace whats_new
+{
+    public static class TLS
+    {
+        public static async Task ConnectCloudFlare()
+        {
+            var targetHost = "www.cloudflare.com";
+
+            using TcpClient tcpClient = new TcpClient();
+
+            await tcpClient.ConnectAsync(targetHost, 443);
+
+            using SslStream sslStream = new SslStream(tcpClient.GetStream());
+
+            await sslStream.AuthenticateAsClientAsync(targetHost);
+            await Console.Out.WriteLineAsync($"Connected to {targetHost} with {sslStream.SslProtocol}");
+        }
+    }
+}
+// </SnippetTLS>

core/whats-new/whats-new-in-30/cs/launch.json

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+{
+  "version": "0.2.0",
+  "configurations": [
+    {
+      "name": ".NET Core Launch (console)",
+      "type": "coreclr",
+      "request": "launch",
+      "preLaunchTask": "build",
+      "program": "${workspaceFolder}/bin/Debug/netcoreapp3.0/whats-new.dll",
+      "args": [],
+      "cwd": "${workspaceFolder}",
+      "console": "internalConsole",
+      "stopAtEntry": false,
+      "internalConsoleOptions": "openOnSessionStart"
+    },
+    {
+      "name": ".NET Core Attach",
+      "type": "coreclr",
+      "request": "attach",
+      "processId": "${command:pickProcess}"
+    }
+  ]
+}

core/whats-new/whats-new-in-30/cs/whats-new.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>netcoreapp3.0</TargetFramework>
+    <RootNamespace>whats_new</RootNamespace>
+    <LangVersion>8.0</LangVersion>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <None Update="launch.json">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </None>
+  </ItemGroup>
+
+</Project>