Add T_URL type for config properties

Makefile.am

@@ -63,6 +63,7 @@ AM_PL_LOG_FLAGS = -Mstrict -w \
 	-MDevel::Autoflush
 handwritten_tests = \
 	t/builtinfw_query.pl \
+	t/check_value.pl \
 	t/get_ip_from_if.pl \
 	t/geturl_connectivity.pl \
 	t/geturl_response.pl \

ddclient.in

@@ -181,6 +181,7 @@ sub T_OFQDN  { 'optional fully qualified host name' }
 sub T_FILE   { 'file name' }
 sub T_FQDNP  { 'fully qualified host name and optional port number' }
 sub T_PROTO  { 'protocol' }
+sub T_URL    { 'url including fully qualified host name, optional port number, and path' }
 sub T_USE    { 'ip strategy' }
 sub T_USEV4  { 'ipv4 strategy' }
 sub T_USEV6  { 'ipv6 strategy' }
@@ -2524,6 +2525,9 @@ sub check_value {
         $value = lc $value;
         return undef if !exists $protocols{$value};
 
+    } elsif ($type eq T_URL) {
+        return undef if $value !~ qr{^(?i:https?://)?[^./]+(\.[^./]+)+(:\d+)?(/[^/]+)*/?$};
+
     } elsif ($type eq T_USE) {
         $value = lc $value;
         return undef if !exists $ip_strategies{$value};

t/check_value.pl

@@ -0,0 +1,47 @@
+use Test::More;
+use strict;
+SKIP: { eval { require Test::Warnings; } or skip($@, 1); }
+eval { require 'ddclient'; } or BAIL_OUT($@);
+
+my @test_cases = (
+    {
+        type  => ddclient::T_FQDN(),
+        input => 'example.com',
+        want  => 'example.com',
+    },
+    {
+        type  => ddclient::T_FQDN(),
+        input => 'example',
+        want  => undef,
+    },
+    {
+        type  => ddclient::T_URL(),
+        input => 'https://www.example.com',
+        want  => 'https://www.example.com',
+    },
+    {
+        type  => ddclient::T_URL(),
+        input => 'https://directnic.com/dns/gateway/ad133/',
+        want  => 'https://directnic.com/dns/gateway/ad133/',
+    },
+    {
+        type  => ddclient::T_URL(),
+        input => 'HTTPS://MixedCase.com/',
+        want  => 'HTTPS://MixedCase.com/',
+    },
+    {
+        type  => ddclient::T_URL(),
+        input => 'ftp://bad.protocol/',
+        want  => undef,
+    },
+    {
+        type  => ddclient::T_URL(),
+        input => 'bad-url',
+        want  => undef,
+    },
+);
+for my $tc (@test_cases) {
+    my $got = ddclient::check_value($tc->{input}, ddclient::setv($tc->{type}, 0, 0, undef, undef));
+    is($got, $tc->{want}, "$tc->{type}: $tc->{input}");
+}
+done_testing();