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>

4 files changed, 22 insertions, 32 deletions

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);