technitium-dns 13.5.0 (new formula)

Add a formula for [Technitium DNS](https://github.com/TechnitiumSoftware/DnsServer),
a self-hosted DNS server for privacy & security which can also block ads & malware
at the DNS level.

The code owner approves this contribution:
TechnitiumSoftware/DnsServer#1294

Author: IngmarStein

Formula/t/technitium-dns.rb

@@ -0,0 +1,67 @@
+class TechnitiumDns < Formula
+  desc "Self host a DNS server for privacy & security"
+  homepage "https://technitium.com/dns/"
+  url "https://github.com/TechnitiumSoftware/DnsServer/archive/refs/tags/v13.5.0.tar.gz"
+  sha256 "7a5f47af4c938c5983e415547b777f853ede5ada8837012c8b5e8e36df1a380e"
+  license "GPL-3.0-or-later"
+
+  depends_on "dotnet@8"
+  depends_on "libmsquic"
+
+  on_linux do
+    depends_on "bind" => :test # for `dig`
+  end
+
+  resource "TechnitiumLibrary" do
+    url "https://github.com/TechnitiumSoftware/TechnitiumLibrary/archive/refs/tags/dns-server-v13.5.0.tar.gz"
+    sha256 "8e0f3200ad6ee6a1ab346a7224a1bc538f6b3dc1b660cd8bb725d0dc09fa2bf9"
+  end
+
+  def install
+    # See https://github.com/TechnitiumSoftware/DnsServer/blob/master/build.md#build-instructions
+    dotnet = Formula["dotnet@8"]
+    mkdir_p "DnsServer"
+    mv Dir.glob("*").reject { |f| f == "DnsServer" }, "DnsServer"
+    resource("TechnitiumLibrary").stage do
+      system "dotnet", "build",
+            "TechnitiumLibrary.ByteTree/TechnitiumLibrary.ByteTree.csproj",
+            "-c", "Release"
+      system "dotnet", "build",
+            "TechnitiumLibrary.Net/TechnitiumLibrary.Net.csproj",
+            "-c", "Release"
+      (buildpath/"TechnitiumLibrary").install Dir.glob("*")
+    end
+    system dotnet.opt_bin/"dotnet", "publish", "DnsServer/DnsServerApp/DnsServerApp.csproj", "-c", "Release"
+    libexec.install Dir["DnsServer/DnsServerApp/bin/Release/publish/*"]
+  end
+
+  service do
+    run [Formula["dotnet@8"].opt_bin/"dotnet", opt_libexec/"DnsServerApp.dll", etc/"technitium-dns"]
+    keep_alive true
+    error_log_path var/"log/technitium-dns.log"
+    log_path var/"log/technitium-dns.log"
+    working_dir var
+  end
+
+  test do
+    # Start the DNS server
+    dotnet = Formula["dotnet@8"]
+    pid = fork do
+      Dir.mktmpdir do |tmpdir|
+        exec "#{dotnet.opt_bin}/dotnet", libexec/"DnsServerApp.dll", tmpdir
+      end
+    end
+    sleep 2 # Give the server time to start
+
+    begin
+      # Use `dig` to resolve "localhost"
+      output = shell_output("dig @127.0.0.1 localhost 2>&1")
+      assert_match "ANSWER SECTION", output
+      assert_match "localhost.", output
+    ensure
+      # Kill the DNS server process
+      Process.kill("KILL", pid)
+      Process.wait(pid)
+    end
+  end
+end