TAP cancallation

Chapter11/04 - Async Downloader With Cancel/.vscode/launch.json

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+{
+   // Use IntelliSense to find out which attributes exist for C# debugging
+   // Use hover for the description of the existing attributes
+   // For further information visit https://github.com/OmniSharp/omnisharp-vscode/blob/master/debugger-launchjson.md
+   "version": "0.2.0",
+   "configurations": [
+        {
+            "name": ".NET Core Launch (console)",
+            "type": "coreclr",
+            "request": "launch",
+            "preLaunchTask": "build",
+            // If you have changed target frameworks, make sure to update the program path.
+            "program": "${workspaceFolder}/bin/Debug/netcoreapp2.1/TaskSample.dll",
+            "args": [],
+            "cwd": "${workspaceFolder}",
+            // For more information about the 'console' field, see https://github.com/OmniSharp/omnisharp-vscode/blob/master/debugger-launchjson.md#console-terminal-window
+            "console": "internalConsole",
+            "stopAtEntry": false,
+            "internalConsoleOptions": "openOnSessionStart"
+        },
+        {
+            "name": ".NET Core Attach",
+            "type": "coreclr",
+            "request": "attach",
+            "processId": "${command:pickProcess}"
+        }
+    ,]
+}

Chapter11/04 - Async Downloader With Cancel/.vscode/tasks.json

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+{
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "build",
+            "command": "dotnet",
+            "type": "process",
+            "args": [
+                "build",
+                "${workspaceFolder}/TaskSample.csproj"
+            ],
+            "problemMatcher": "$msCompile"
+        }
+    ]
+}

Chapter11/04 - Async Downloader With Cancel/Program.cs

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+using System;
+using System.Collections.Generic;
+using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace TaskSample
+{
+    class Program
+    {
+        static async Task Main(string[] args)
+        {
+            try
+            {
+                var result = await DownloadHomePages();
+                foreach (var item in result)
+                    Console.WriteLine(item);
+            }
+            catch (AggregateException ex)
+            {
+                Console.WriteLine(ex.Flatten().InnerException.Message);
+            }
+        }
+        static Task<List<string>> DownloadHomePages()
+        {
+            var client = new HttpClient();
+            var bag = new List<string>();
+            var source = new CancellationTokenSource();
+            var token = source.Token;
+            var sites = new string[] {"https://www.packtpub.com","https://www.amazon.com","https://www.google.com",
+    "https://www.apple.com","https://www.salesforce.com","http://www.microsoft.com","http://www.oracle.com",
+    "https://www.ibm.com","https://www.redhat.com","https://www.ubuntu.com","https://www.adobe.com",
+    "https://www.autodesk.com","https://www.embarcadero.com"};
+            var task = Task.Factory.StartNew(() =>
+             {
+                 foreach (var site in sites)
+                 {
+                     Console.WriteLine($"Processing {site}");
+                     token.ThrowIfCancellationRequested();
+                     bag.Add(client.GetStringAsync(site).Result);
+                 }
+             }, token);
+            // Cancel after 3 seconds
+            source.CancelAfter(TimeSpan.FromSeconds(3));
+            task.Wait();
+            return Task.FromResult(bag);
+
+        }
+    }
+}

Chapter11/04 - Async Downloader With Cancel/TaskSample.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>netcoreapp2.1</TargetFramework>
+    <LangVersion>latest</LangVersion>
+  </PropertyGroup>
+
+</Project>