useragent: Automatically choose whether to use LWPx::ParanoidAgent

The simple implementation of this, which I'd prefer to use, would be:
if we can import LWPx::ParanoidAgent, use it; otherwise, use
LWP::UserAgent.

However, aggregate has historically worked with proxies, and
LWPx::ParanoidAgent quite reasonably refuses to work with proxies
(because it can't know whether those proxies are going to do the same
filtering that LWPx::ParanoidAgent would).

Signed-off-by: Simon McVittie <smcv@debian.org>

6 files changed, 458 insertions, 36 deletions

diff --git a/IkiWiki.pm b/IkiWiki.pm
index d5d1af56c..efb48293a 100644
--- a/IkiWiki.pm
+++ b/IkiWiki.pm
@@ -2469,16 +2469,131 @@ sub add_autofile ($$$) {
 	$autofiles{$file}{generator}=$generator;
 }
 
-sub useragent () {
+sub useragent (@) {
+	my %params = @_;
+	my $for_url = delete $params{for_url};
+	# Fail safe, in case a plugin calling this function is relying on
+	# a future parameter to make the UA more strict
+	foreach my $key (keys %params) {
+		error "Internal error: useragent(\"$key\" => ...) not understood";
+	}
+
 	eval q{use LWP};
 	error($@) if $@;
 
-	return LWP::UserAgent->new(
-		cookie_jar => $config{cookiejar},
-		env_proxy => 1,		# respect proxy env vars
+	my %args = (
 		agent => $config{useragent},
+		cookie_jar => $config{cookiejar},
+		env_proxy => 0,
 		protocols_allowed => [qw(http https)],
 	);
+	my %proxies;
+
+	if (defined $for_url) {
+		# We know which URL we're going to fetch, so we can choose
+		# whether it's going to go through a proxy or not.
+		#
+		# We reimplement http_proxy, https_proxy and no_proxy here, so
+		# that we are not relying on LWP implementing them exactly the
+		# same way we do.
+
+		eval q{use URI};
+		error($@) if $@;
+
+		my $proxy;
+		my $uri = URI->new($for_url);
+
+		if ($uri->scheme eq 'http') {
+			$proxy = $ENV{http_proxy};
+			# HTTP_PROXY is deliberately not implemented
+			# because the HTTP_* namespace is also used by CGI
+		}
+		elsif ($uri->scheme eq 'https') {
+			$proxy = $ENV{https_proxy};
+			$proxy = $ENV{HTTPS_PROXY} unless defined $proxy;
+		}
+		else {
+			$proxy = undef;
+		}
+
+		foreach my $var (qw(no_proxy NO_PROXY)) {
+			my $no_proxy = $ENV{$var};
+			if (defined $no_proxy) {
+				foreach my $domain (split /\s*,\s*/, $no_proxy) {
+					if ($domain =~ s/^\*?\.//) {
+						# no_proxy="*.example.com" or
+						# ".example.com": match suffix
+						# against .example.com
+						if ($uri->host =~ m/(^|\.)\Q$domain\E$/i) {
+							$proxy = undef;
+						}
+					}
+					else {
+						# no_proxy="example.com":
+						# match exactly example.com
+						if (lc $uri->host eq lc $domain) {
+							$proxy = undef;
+						}
+					}
+				}
+			}
+		}
+
+		if (defined $proxy) {
+			$proxies{$uri->scheme} = $proxy;
+			# Paranoia: make sure we can't bypass the proxy
+			$args{protocols_allowed} = [$uri->scheme];
+		}
+	}
+	else {
+		# The plugin doesn't know yet which URL(s) it's going to
+		# fetch, so we have to make some conservative assumptions.
+		my $http_proxy = $ENV{http_proxy};
+		my $https_proxy = $ENV{https_proxy};
+		$https_proxy = $ENV{HTTPS_PROXY} unless defined $https_proxy;
+
+		# We don't respect no_proxy here: if we are not using the
+		# paranoid user-agent, then we need to give the proxy the
+		# opportunity to reject undesirable requests.
+
+		# If we have one, we need the other: otherwise, neither
+		# LWPx::ParanoidAgent nor the proxy would have the
+		# opportunity to filter requests for the other protocol.
+		if (defined $https_proxy && defined $http_proxy) {
+			%proxies = (http => $http_proxy, https => $https_proxy);
+		}
+		elsif (defined $https_proxy) {
+			%proxies = (http => $https_proxy, https => $https_proxy);
+		}
+		elsif (defined $http_proxy) {
+			%proxies = (http => $http_proxy, https => $http_proxy);
+		}
+
+	}
+
+	if (scalar keys %proxies) {
+		# The configured proxy is responsible for deciding which
+		# URLs are acceptable to fetch and which URLs are not.
+		my $ua = LWP::UserAgent->new(%args);
+		foreach my $scheme (@{$ua->protocols_allowed}) {
+			unless ($proxies{$scheme}) {
+				error "internal error: $scheme is allowed but has no proxy";
+			}
+		}
+		# We can't pass the proxies in %args because that only
+		# works since LWP 6.24.
+		foreach my $scheme (keys %proxies) {
+			$ua->proxy($scheme, $proxies{$scheme});
+		}
+		return $ua;
+	}
+
+	eval q{use LWPx::ParanoidAgent};
+	if ($@) {
+		print STDERR "warning: installing LWPx::ParanoidAgent is recommended\n";
+		return LWP::UserAgent->new(%args);
+	}
+	return LWPx::ParanoidAgent->new(%args);
 }
 
 sub sortspec_translate ($$) {
diff --git a/IkiWiki/Plugin/aggregate.pm b/IkiWiki/Plugin/aggregate.pm
index 05e22a290..8f0870e2e 100644
--- a/IkiWiki/Plugin/aggregate.pm
+++ b/IkiWiki/Plugin/aggregate.pm
@@ -513,7 +513,10 @@ sub aggregate (@) {
 			}
 			$feed->{feedurl}=pop @urls;
 		}
-		my $ua=useragent();
+		# Using the for_url parameter makes sure we crash if used
+		# with an older IkiWiki.pm that didn't automatically try
+		# to use LWPx::ParanoidAgent.
+		my $ua=useragent(for_url => $feed->{feedurl});
 		my $res=URI::Fetch->fetch($feed->{feedurl}, UserAgent=>$ua);
 		if (! $res) {
 			$feed->{message}=URI::Fetch->errstr;
diff --git a/IkiWiki/Plugin/blogspam.pm b/IkiWiki/Plugin/blogspam.pm
index 3eb4cf8b3..3835f52ca 100644
--- a/IkiWiki/Plugin/blogspam.pm
+++ b/IkiWiki/Plugin/blogspam.pm
@@ -57,18 +57,10 @@ sub checkconfig () {
 	};
 	error $@ if $@;
 
-	eval q{use LWPx::ParanoidAgent};
-	if (!$@) {
-		$client=LWPx::ParanoidAgent->new(agent => $config{useragent});
-	}
-	else {
-		eval q{use LWP};
-		if ($@) {
-			error $@;
-			return;
-		}
-		$client=useragent();
-	}
+	# Using the for_url parameter makes sure we crash if used
+	# with an older IkiWiki.pm that didn't automatically try
+	# to use LWPx::ParanoidAgent.
+	$client=useragent(for_url => $config{blogspam_server});
 }
 
 sub checkcontent (@) {
diff --git a/IkiWiki/Plugin/openid.pm b/IkiWiki/Plugin/openid.pm
index 35ef52a58..eb21955e9 100644
--- a/IkiWiki/Plugin/openid.pm
+++ b/IkiWiki/Plugin/openid.pm
@@ -219,14 +219,10 @@ sub getobj ($$) {
 	eval q{use Net::OpenID::Consumer};
 	error($@) if $@;
 
-	my $ua;
-	eval q{use LWPx::ParanoidAgent};
-	if (! $@) {
-		$ua=LWPx::ParanoidAgent->new(agent => $config{useragent});
-	}
-	else {
-		$ua=useragent();
-	}
+	# We pass the for_url parameter, even though it's undef, because
+	# that will make sure we crash if used with an older IkiWiki.pm
+	# that didn't automatically try to use LWPx::ParanoidAgent.
+	my $ua=useragent(for_url => undef);
 
 	# Store the secret in the session.
 	my $secret=$session->param("openid_secret");
diff --git a/IkiWiki/Plugin/pinger.pm b/IkiWiki/Plugin/pinger.pm
index b2d54af8a..ec764caee 100644
--- a/IkiWiki/Plugin/pinger.pm
+++ b/IkiWiki/Plugin/pinger.pm
@@ -70,17 +70,16 @@ sub ping {
 		eval q{use Net::INET6Glue::INET_is_INET6}; # may not be available
 		
 		my $ua;
-		eval q{use LWPx::ParanoidAgent};
-		if (!$@) {
-			$ua=LWPx::ParanoidAgent->new(agent => $config{useragent});
-		}
-		else {
-			eval q{use LWP};
-			if ($@) {
-				debug(gettext("LWP not found, not pinging"));
-				return;
-			}
-			$ua=useragent();
+		eval {
+			# We pass the for_url parameter, even though it's
+			# undef, because that will make sure we crash if used
+			# with an older IkiWiki.pm that didn't automatically
+			# try to use LWPx::ParanoidAgent.
+			$ua=useragent(for_url => undef);
+		};
+		if ($@) {
+			debug(gettext("LWP not found, not pinging").": $@");
+			return;
 		}
 		$ua->timeout($config{pinger_timeout} || 15);
 		
diff --git a/t/useragent.t b/t/useragent.t
new file mode 100755
index 000000000..195a86521
--- /dev/null
+++ b/t/useragent.t
@@ -0,0 +1,317 @@
+#!/usr/bin/perl
+use warnings;
+use strict;
+use Test::More;
+
+my $have_paranoid_agent;
+BEGIN {
+	plan(skip_all => 'LWP not available')
+		unless eval q{
+			use LWP qw(); 1;
+		};
+	use_ok("IkiWiki");
+	$have_paranoid_agent = eval q{
+		use LWPx::ParanoidAgent qw(); 1;
+	};
+}
+
+eval { useragent(future_feature => 1); };
+ok($@, 'future features should cause useragent to fail');
+
+diag "==== No proxy ====";
+delete $ENV{http_proxy};
+delete $ENV{https_proxy};
+delete $ENV{no_proxy};
+delete $ENV{HTTPS_PROXY};
+delete $ENV{NO_PROXY};
+
+diag "---- Unspecified URL ----";
+my $ua = useragent(for_url => undef);
+SKIP: {
+	skip 'paranoid agent not available', 1 unless $have_paranoid_agent;
+	ok($ua->isa('LWPx::ParanoidAgent'), 'uses ParanoidAgent if possible');
+}
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http https)]);
+is($ua->proxy('http'), undef, 'No http proxy');
+is($ua->proxy('https'), undef, 'No https proxy');
+
+diag "---- Specified URL ----";
+$ua = useragent(for_url => 'http://example.com');
+SKIP: {
+	skip 'paranoid agent not available', 1 unless $have_paranoid_agent;
+	ok($ua->isa('LWPx::ParanoidAgent'), 'uses ParanoidAgent if possible');
+}
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http https)]);
+is($ua->proxy('http'), undef, 'No http proxy');
+is($ua->proxy('https'), undef, 'No https proxy');
+
+diag "==== Proxy for everything ====";
+$ENV{http_proxy} = 'http://proxy:8080';
+$ENV{https_proxy} = 'http://sproxy:8080';
+delete $ENV{no_proxy};
+delete $ENV{HTTPS_PROXY};
+delete $ENV{NO_PROXY};
+
+diag "---- Unspecified URL ----";
+$ua = useragent(for_url => undef);
+ok(! $ua->isa('LWPx::ParanoidAgent'), 'should use proxy instead of ParanoidAgent');
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http https)]);
+is($ua->proxy('http'), 'http://proxy:8080', 'should use proxy');
+is($ua->proxy('https'), 'http://sproxy:8080', 'should use CONNECT proxy');
+$ua = useragent(for_url => 'http://example.com');
+ok(! $ua->isa('LWPx::ParanoidAgent'), 'should use proxy instead of ParanoidAgent');
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http)]);
+is($ua->proxy('http'), 'http://proxy:8080', 'should use proxy');
+# We don't care what $ua->proxy('https') is, because it won't be used
+$ua = useragent(for_url => 'https://example.com');
+ok(! $ua->isa('LWPx::ParanoidAgent'), 'should use proxy instead of ParanoidAgent');
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(https)]);
+# We don't care what $ua->proxy('http') is, because it won't be used
+is($ua->proxy('https'), 'http://sproxy:8080', 'should use CONNECT proxy');
+
+diag "==== Selective proxy ====";
+$ENV{http_proxy} = 'http://proxy:8080';
+$ENV{https_proxy} = 'http://sproxy:8080';
+$ENV{no_proxy} = '*.example.net,example.com,.example.org';
+delete $ENV{HTTPS_PROXY};
+delete $ENV{NO_PROXY};
+
+diag "---- Unspecified URL ----";
+$ua = useragent(for_url => undef);
+ok(! $ua->isa('LWPx::ParanoidAgent'), 'should use proxy instead of ParanoidAgent');
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http https)]);
+is($ua->proxy('http'), 'http://proxy:8080', 'should use proxy');
+is($ua->proxy('https'), 'http://sproxy:8080', 'should use CONNECT proxy');
+
+diag "---- Exact match for no_proxy ----";
+$ua = useragent(for_url => 'http://example.com');
+SKIP: {
+	skip 'paranoid agent not available', 1 unless $have_paranoid_agent;
+	ok($ua->isa('LWPx::ParanoidAgent'), 'uses ParanoidAgent if possible');
+}
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http https)]);
+is($ua->proxy('http'), undef);
+is($ua->proxy('https'), undef);
+
+diag "---- Subdomain of exact domain in no_proxy ----";
+$ua = useragent(for_url => 'http://sub.example.com');
+ok(! $ua->isa('LWPx::ParanoidAgent'), 'should use proxy instead of ParanoidAgent');
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http)]);
+is($ua->proxy('http'), 'http://proxy:8080', 'should use proxy');
+
+diag "---- example.net matches *.example.net ----";
+$ua = useragent(for_url => 'https://example.net');
+SKIP: {
+	skip 'paranoid agent not available', 1 unless $have_paranoid_agent;
+	ok($ua->isa('LWPx::ParanoidAgent'), 'uses ParanoidAgent if possible');
+}
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http https)]);
+is($ua->proxy('http'), undef);
+is($ua->proxy('https'), undef);
+
+diag "---- sub.example.net matches *.example.net ----";
+$ua = useragent(for_url => 'https://sub.example.net');
+SKIP: {
+	skip 'paranoid agent not available', 1 unless $have_paranoid_agent;
+	ok($ua->isa('LWPx::ParanoidAgent'), 'uses ParanoidAgent if possible');
+}
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http https)]);
+is($ua->proxy('http'), undef);
+is($ua->proxy('https'), undef);
+
+diag "---- badexample.net does not match *.example.net ----";
+$ua = useragent(for_url => 'https://badexample.net');
+ok(! $ua->isa('LWPx::ParanoidAgent'), 'should use proxy instead of ParanoidAgent');
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(https)]);
+is($ua->proxy('https'), 'http://sproxy:8080', 'should use proxy');
+
+diag "---- example.org matches .example.org ----";
+$ua = useragent(for_url => 'https://example.org');
+SKIP: {
+	skip 'paranoid agent not available', 1 unless $have_paranoid_agent;
+	ok($ua->isa('LWPx::ParanoidAgent'), 'uses ParanoidAgent if possible');
+}
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http https)]);
+is($ua->proxy('http'), undef);
+is($ua->proxy('https'), undef);
+
+diag "---- sub.example.org matches .example.org ----";
+$ua = useragent(for_url => 'https://sub.example.org');
+SKIP: {
+	skip 'paranoid agent not available', 1 unless $have_paranoid_agent;
+	ok($ua->isa('LWPx::ParanoidAgent'), 'uses ParanoidAgent if possible');
+}
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http https)]);
+is($ua->proxy('http'), undef);
+is($ua->proxy('https'), undef);
+
+diag "---- badexample.org does not match .example.org ----";
+$ua = useragent(for_url => 'https://badexample.org');
+ok(! $ua->isa('LWPx::ParanoidAgent'), 'should use proxy instead of ParanoidAgent');
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(https)]);
+is($ua->proxy('https'), 'http://sproxy:8080', 'should use proxy');
+
+diag "==== Selective proxy (alternate variables) ====";
+$ENV{http_proxy} = 'http://proxy:8080';
+delete $ENV{https_proxy};
+$ENV{HTTPS_PROXY} = 'http://sproxy:8080';
+delete $ENV{no_proxy};
+$ENV{NO_PROXY} = '*.example.net,example.com,.example.org';
+
+diag "---- Unspecified URL ----";
+$ua = useragent(for_url => undef);
+ok(! $ua->isa('LWPx::ParanoidAgent'), 'should use proxy instead of ParanoidAgent');
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http https)]);
+is($ua->proxy('http'), 'http://proxy:8080', 'should use proxy');
+is($ua->proxy('https'), 'http://sproxy:8080', 'should use CONNECT proxy');
+
+diag "---- Exact match for no_proxy ----";
+$ua = useragent(for_url => 'http://example.com');
+SKIP: {
+	skip 'paranoid agent not available', 1 unless $have_paranoid_agent;
+	ok($ua->isa('LWPx::ParanoidAgent'), 'uses ParanoidAgent if possible');
+}
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http https)]);
+is($ua->proxy('http'), undef);
+is($ua->proxy('https'), undef);
+
+diag "---- Subdomain of exact domain in no_proxy ----";
+$ua = useragent(for_url => 'http://sub.example.com');
+ok(! $ua->isa('LWPx::ParanoidAgent'), 'should use proxy instead of ParanoidAgent');
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http)]);
+is($ua->proxy('http'), 'http://proxy:8080', 'should use proxy');
+
+diag "---- example.net matches *.example.net ----";
+$ua = useragent(for_url => 'https://example.net');
+SKIP: {
+	skip 'paranoid agent not available', 1 unless $have_paranoid_agent;
+	ok($ua->isa('LWPx::ParanoidAgent'), 'uses ParanoidAgent if possible');
+}
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http https)]);
+is($ua->proxy('http'), undef);
+is($ua->proxy('https'), undef);
+
+diag "---- sub.example.net matches *.example.net ----";
+$ua = useragent(for_url => 'https://sub.example.net');
+SKIP: {
+	skip 'paranoid agent not available', 1 unless $have_paranoid_agent;
+	ok($ua->isa('LWPx::ParanoidAgent'), 'uses ParanoidAgent if possible');
+}
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http https)]);
+is($ua->proxy('http'), undef);
+is($ua->proxy('https'), undef);
+
+diag "---- badexample.net does not match *.example.net ----";
+$ua = useragent(for_url => 'https://badexample.net');
+ok(! $ua->isa('LWPx::ParanoidAgent'), 'should use proxy instead of ParanoidAgent');
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(https)]);
+is($ua->proxy('https'), 'http://sproxy:8080', 'should use proxy');
+
+diag "---- example.org matches .example.org ----";
+$ua = useragent(for_url => 'https://example.org');
+SKIP: {
+	skip 'paranoid agent not available', 1 unless $have_paranoid_agent;
+	ok($ua->isa('LWPx::ParanoidAgent'), 'uses ParanoidAgent if possible');
+}
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http https)]);
+is($ua->proxy('http'), undef);
+is($ua->proxy('https'), undef);
+
+diag "---- sub.example.org matches .example.org ----";
+$ua = useragent(for_url => 'https://sub.example.org');
+SKIP: {
+	skip 'paranoid agent not available', 1 unless $have_paranoid_agent;
+	ok($ua->isa('LWPx::ParanoidAgent'), 'uses ParanoidAgent if possible');
+}
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http https)]);
+is($ua->proxy('http'), undef);
+is($ua->proxy('https'), undef);
+
+diag "---- badexample.org does not match .example.org ----";
+$ua = useragent(for_url => 'https://badexample.org');
+ok(! $ua->isa('LWPx::ParanoidAgent'), 'should use proxy instead of ParanoidAgent');
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(https)]);
+is($ua->proxy('https'), 'http://sproxy:8080', 'should use proxy');
+
+diag "==== Selective proxy (many variables) ====";
+$ENV{http_proxy} = 'http://proxy:8080';
+$ENV{https_proxy} = 'http://sproxy:8080';
+# This one should be ignored in favour of https_proxy
+$ENV{HTTPS_PROXY} = 'http://not.preferred.proxy:3128';
+# These two should be merged
+$ENV{no_proxy} = '*.example.net,example.com';
+$ENV{NO_PROXY} = '.example.org';
+
+diag "---- Unspecified URL ----";
+$ua = useragent(for_url => undef);
+ok(! $ua->isa('LWPx::ParanoidAgent'), 'should use proxy instead of ParanoidAgent');
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http https)]);
+is($ua->proxy('http'), 'http://proxy:8080', 'should use proxy');
+is($ua->proxy('https'), 'http://sproxy:8080', 'should use CONNECT proxy');
+
+diag "---- Exact match for no_proxy ----";
+$ua = useragent(for_url => 'http://example.com');
+SKIP: {
+	skip 'paranoid agent not available', 1 unless $have_paranoid_agent;
+	ok($ua->isa('LWPx::ParanoidAgent'), 'uses ParanoidAgent if possible');
+}
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http https)]);
+is($ua->proxy('http'), undef);
+is($ua->proxy('https'), undef);
+
+diag "---- Subdomain of exact domain in no_proxy ----";
+$ua = useragent(for_url => 'http://sub.example.com');
+ok(! $ua->isa('LWPx::ParanoidAgent'), 'should use proxy instead of ParanoidAgent');
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http)]);
+is($ua->proxy('http'), 'http://proxy:8080', 'should use proxy');
+
+diag "---- example.net matches *.example.net ----";
+$ua = useragent(for_url => 'https://example.net');
+SKIP: {
+	skip 'paranoid agent not available', 1 unless $have_paranoid_agent;
+	ok($ua->isa('LWPx::ParanoidAgent'), 'uses ParanoidAgent if possible');
+}
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http https)]);
+is($ua->proxy('http'), undef);
+is($ua->proxy('https'), undef);
+
+diag "---- sub.example.net matches *.example.net ----";
+$ua = useragent(for_url => 'https://sub.example.net');
+SKIP: {
+	skip 'paranoid agent not available', 1 unless $have_paranoid_agent;
+	ok($ua->isa('LWPx::ParanoidAgent'), 'uses ParanoidAgent if possible');
+}
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http https)]);
+is($ua->proxy('http'), undef);
+is($ua->proxy('https'), undef);
+
+diag "---- badexample.net does not match *.example.net ----";
+$ua = useragent(for_url => 'https://badexample.net');
+ok(! $ua->isa('LWPx::ParanoidAgent'), 'should use proxy instead of ParanoidAgent');
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(https)]);
+is($ua->proxy('https'), 'http://sproxy:8080', 'should use proxy');
+
+diag "==== One but not the other ====\n";
+$ENV{http_proxy} = 'http://proxy:8080';
+delete $ENV{https_proxy};
+delete $ENV{HTTPS_PROXY};
+delete $ENV{no_proxy};
+delete $ENV{NO_PROXY};
+$ua = useragent(for_url => undef);
+ok(! $ua->isa('LWPx::ParanoidAgent'), 'should use proxy instead of ParanoidAgent');
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http https)]);
+is($ua->proxy('http'), 'http://proxy:8080', 'should use proxy');
+is($ua->proxy('https'), 'http://proxy:8080', 'should use proxy');
+
+delete $ENV{http_proxy};
+$ENV{https_proxy} = 'http://sproxy:8080';
+delete $ENV{HTTPS_PROXY};
+delete $ENV{no_proxy};
+delete $ENV{NO_PROXY};
+$ua = useragent(for_url => undef);
+ok(! $ua->isa('LWPx::ParanoidAgent'), 'should use proxy instead of ParanoidAgent');
+is_deeply([sort @{$ua->protocols_allowed}], [sort qw(http https)]);
+is($ua->proxy('http'), 'http://sproxy:8080', 'should use proxy');
+is($ua->proxy('https'), 'http://sproxy:8080', 'should use proxy');
+
+done_testing;