Initial commit

vscode/Chapter08/WorkingWithNetworkResources/Program.cs

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+using System.Net; // IPHostEntry, Dns, IPAddress
+using System.Net.NetworkInformation; // Ping, PingReply, IPStatus
+
+// Working with URIs, DNS, and IP addresses
+
+Write("Enter a valid web address (or press Enter): ");
+string? url = ReadLine();
+
+if (string.IsNullOrWhiteSpace(url)) // if they enter nothing...
+{
+  // ... set a default URL
+  url = "https://stackoverflow.com/search?q=securestring";
+}
+
+Uri uri = new(url);
+WriteLine($"URL: {url}");
+WriteLine($"Scheme: {uri.Scheme}");
+WriteLine($"Port: {uri.Port}");
+WriteLine($"Host: {uri.Host}");
+WriteLine($"Path: {uri.AbsolutePath}");
+WriteLine($"Query: {uri.Query}");
+
+IPHostEntry entry = Dns.GetHostEntry(uri.Host);
+WriteLine($"{entry.HostName} has the following IP addresses:");
+foreach (IPAddress address in entry.AddressList)
+{
+  WriteLine($"  {address} ({address.AddressFamily})");
+}
+
+// Pinging a server
+
+try
+{
+  Ping ping = new();
+
+  WriteLine("Pinging server. Please wait...");
+  PingReply reply = ping.Send(uri.Host);
+  WriteLine($"{uri.Host} was pinged and replied: {reply.Status}.");
+
+  if (reply.Status == IPStatus.Success)
+  {
+    WriteLine("Reply from {0} took {1:N0}ms",
+      arg0: reply.Address,
+      arg1: reply.RoundtripTime);
+  }
+}
+catch (Exception ex)
+{
+  WriteLine($"{ex.GetType().ToString()} says {ex.Message}");
+}