Fix HTTP::Client certificate validation error on FQDN (host with tr…

…ailing dot) (crystal-lang#12778)

Co-authored-by: Quinton Miller <[email protected]>

spec/manual/https_client_spec.cr

@@ -7,6 +7,10 @@ describe "https requests" do
     HTTP::Client.get("https://google.com")
   end
 
+  it "can fetch from google.com. FQDN with trailing dot (#12777)" do
+    HTTP::Client.get("https://google.com.")
+  end
+
   it "can close request before consuming body" do
     HTTP::Client.get("https://crystal-lang.org") do
       break

spec/std/uri_spec.cr

@@ -68,6 +68,10 @@ describe "URI" do
     assert_uri("http://[::1]:81/", scheme: "http", host: "[::1]", port: 81, path: "/")
     assert_uri("http://192.0.2.16:81/", scheme: "http", host: "192.0.2.16", port: 81, path: "/")
 
+    # preserves fully-qualified host with trailing dot
+    assert_uri("https://example.com./", scheme: "https", host: "example.com.", path: "/")
+    assert_uri("https://example.com.:8443/", scheme: "https", host: "example.com.", port: 8443, path: "/")
+
     # port
     it { URI.parse("http://192.168.0.2:/foo").should eq URI.new(scheme: "http", host: "192.168.0.2", path: "/foo") }
 

src/http/client.cr

@@ -801,7 +801,7 @@ class HTTP::Client
       if tls = @tls
         tcp_socket = io
         begin
-          io = OpenSSL::SSL::Socket::Client.new(tcp_socket, context: tls, sync_close: true, hostname: @host)
+          io = OpenSSL::SSL::Socket::Client.new(tcp_socket, context: tls, sync_close: true, hostname: @host.rchop('.'))
         rescue exc
           # don't leak the TCP socket when the SSL connection failed
           tcp_socket.close