Enhance the link plugin to handle external links.

The following ways to create a link are supported now:
[[url]]
[[text|url]]
url can be one of the following:
- an internal wikilink: will be handled as before
- any other kind of URL, including mailto: proper links will be created:
  <a href="url">url</a>
  <a href="url">text</a>
- an email address:
  <a href="mailto:url">url</a>
  <a href="mailto:url">text</a>

2 files changed, 68 insertions, 23 deletions

diff --git a/IkiWiki/Plugin/link.pm b/IkiWiki/Plugin/link.pm
index 3838aec09..d41965bd3 100644
--- a/IkiWiki/Plugin/link.pm
+++ b/IkiWiki/Plugin/link.pm
@@ -7,6 +7,9 @@ use IkiWiki 3.00;
 
 my $link_regexp;
 
+my $email_regexp = qr/^(?:[a-z0-9!#$%&'*+\/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+\/=?^_`{|}~-]+)*|"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])*")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])+)\])$/i; 
+my $url_regexp = qr/^(?:[^:]+:\/\/|mailto:).*/i;
+
 sub import {
 	hook(type => "getsetup", id => "link", call => \&getsetup);
 	hook(type => "checkconfig", id => "link", call => \&checkconfig);
@@ -57,8 +60,42 @@ sub checkconfig () {
 			)?                      # optional
 
 			\]\]                    # end of link
-		}x,
+		}x;
+	}
+}
+
+sub is_externallink ($$) {
+	my $page = shift;
+	my $url = shift;
+	if ($url =~ /$email_regexp/) {
+		# url looks like an email address, so we assume it
+		# is supposed to be an external link if there is no
+		# page with that name.
+		$url =~ s/#.*//;
+		return (! (bestlink($page, linkpage($url))))
 	}
+	return ($url =~ /$url_regexp/)
+}
+
+sub externallink ($;@) {
+	my $url = shift;
+	my $pagetitle = shift;
+
+	# build pagetitle
+	if (!($pagetitle)) {
+		$pagetitle = $url;
+		# use only the email address as title for mailto: urls
+		if ($pagetitle =~ /^mailto:.*/) {
+			$pagetitle =~ s/^mailto:([^?]+).*/$1/;
+		}
+	}
+
+	# handle email-addresses (without mailto:):
+	if ($url =~ /$email_regexp/) {
+		$url = "mailto:" . $url;
+	}
+
+	return "<a href=\"$url\">$pagetitle</a>";
 }
 
 sub linkify (@) {
@@ -70,12 +107,16 @@ sub linkify (@) {
 		defined $2
 			? ( $1 
 				? "[[$2|$3".($4 ? "#$4" : "")."]]" 
-				: htmllink($page, $destpage, linkpage($3),
-					anchor => $4, linktext => pagetitle($2)))
+				: is_externallink($page, $3 . ($4 ? "#$4" : ""))
+					? externallink("$3" . ($4 ? "#$4" : ""), $2)
+					: htmllink($page, $destpage, linkpage($3),
+						anchor => $4, linktext => pagetitle($2)))
 			: ( $1 
 				? "[[$3".($4 ? "#$4" : "")."]]"
-				: htmllink($page, $destpage, linkpage($3),
-					anchor => $4))
+				: is_externallink($page, $3 . ($4 ? "#$4" : ""))
+					? externallink("$3" . ($4 ? "#$4" : ""))
+					: htmllink($page, $destpage, linkpage($3),
+						anchor => $4))
 	}eg;
 	
 	return $params{content};
@@ -87,7 +128,9 @@ sub scan (@) {
 	my $content=$params{content};
 
 	while ($content =~ /(?<!\\)$link_regexp/g) {
-		add_link($page, linkpage($2));
+		if (! is_externallink($page, $2 . ($3 ? "#$3" : ""))) {
+			add_link($page, linkpage($2));
+		}
 	}
 }
 
@@ -98,24 +141,26 @@ sub renamepage (@) {
 	my $new=$params{newpage};
 
 	$params{content} =~ s{(?<!\\)$link_regexp}{
-		my $linktext=$2;
-		my $link=$linktext;
-		if (bestlink($page, linkpage($linktext)) eq $old) {
-			$link=pagetitle($new, 1);
-			$link=~s/ /_/g;
-			if ($linktext =~ m/.*\/*?[A-Z]/) {
-				# preserve leading cap of last component
-				my @bits=split("/", $link);
-				$link=join("/", @bits[0..$#bits-1], ucfirst($bits[$#bits]));
-			}
-			if (index($linktext, "/") == 0) {
-				# absolute link
-				$link="/$link";
+		if (! is_externallink($page, $2 . ($3 ? "#$3" : ""))) {
+			my $linktext=$2;
+			my $link=$linktext;
+			if (bestlink($page, linkpage($linktext)) eq $old) {
+				$link=pagetitle($new, 1);
+				$link=~s/ /_/g;
+				if ($linktext =~ m/.*\/*?[A-Z]/) {
+					# preserve leading cap of last component
+					my @bits=split("/", $link);
+					$link=join("/", @bits[0..$#bits-1], ucfirst($bits[$#bits]));
+				}
+				if (index($linktext, "/") == 0) {
+					# absolute link
+					$link="/$link";
+				}
 			}
+			defined $1
+				? ( "[[$1|$link".($3 ? "#$3" : "")."]]" )
+				: ( "[[$link".   ($3 ? "#$3" : "")."]]" )
 		}
-		defined $1
-			? ( "[[$1|$link".($3 ? "#$3" : "")."]]" )
-			: ( "[[$link".   ($3 ? "#$3" : "")."]]" )
 	}eg;
 
 	return $params{content};
diff --git a/doc/plugins/link.mdwn b/doc/plugins/link.mdwn
index 6adbf3eae..5de4fe3cb 100644
--- a/doc/plugins/link.mdwn
+++ b/doc/plugins/link.mdwn
@@ -1,4 +1,4 @@
 [[!template id=plugin name=link core=1 author="[[Joey]]"]]
 [[!tag type/link]]
 
-This plugin implements standard [[WikiLinks|ikiwiki/wikilink]].
+This plugin implements standard [[WikiLinks|ikiwiki/wikilink]] and links to [[external pages|http://www.debian.org]].