allow users to subscribe to comments w/o registering

Technically, when the user does this, a passwordless account is created
for them. The notify mails include a login url, and once logged in that
way, the user can enter a password to get a regular account (although
one with an annoying username).

This all requires the passwordauth plugin is enabled. A future enhancement
could be to split the passwordless user concept out into a separate plugin.

IkiWiki/Plugin/comments.pm

@@ -302,7 +302,7 @@ sub editcomment ($$) {
 	my @buttons = (POST_COMMENT, PREVIEW, CANCEL);
 	my $form = CGI::FormBuilder->new(
 		fields => [qw{do sid page subject editcontent type author
-			url subscribe}],
+			email url subscribe anonsubscribe}],
 		charset => 'utf-8',
 		method => 'POST',
 		required => [qw{editcontent}],
@@ -349,24 +349,33 @@ sub editcomment ($$) {
 
 	my $username=$session->param('name');
 	$form->tmpl_param(username => $username);
-	if (defined $username && IkiWiki::Plugin::notifyemail->can("subscribe")) {
-		$form->field(name => "subscribe",
-			options => [gettext("email replies to me")]);
-	}
-	else {
-		$form->field(name => "subscribe", type => 'hidden');
+		
+	$form->field(name => "subscribe", type => 'hidden');
+	$form->field(name => "anonsubscribe", type => 'hidden');
+	if (IkiWiki::Plugin::notifyemail->can("subscribe")) {
+		if (defined $username) {
+			$form->field(name => "subscribe", type => "checkbox",
+				options => [gettext("email replies to me")]);
+		}
+		elsif (IkiWiki::Plugin::passwordauth->can("anonuser")) {
+			$form->field(name => "anonsubscribe", type => "checkbox",
+				options => [gettext("email replies to me")]);
+		}
 	}
 
 	if ($config{comments_allowauthor} and
 	    ! defined $session->param('name')) {
 		$form->tmpl_param(allowauthor => 1);
 		$form->field(name => 'author', type => 'text', size => '40');
+		$form->field(name => 'email', type => 'text', size => '40');
 		$form->field(name => 'url', type => 'text', size => '40');
 	}
 	else {
 		$form->tmpl_param(allowauthor => 0);
 		$form->field(name => 'author', type => 'hidden', value => '',
 			force => 1);
+		$form->field(name => 'email', type => 'hidden', value => '',
+			force => 1);
 		$form->field(name => 'url', type => 'hidden', value => '',
 			force => 1);
 	}
@@ -500,10 +509,18 @@ sub editcomment ($$) {
 	if ($form->submitted eq POST_COMMENT && $form->validate) {
 		IkiWiki::checksessionexpiry($cgi, $session);
 
-		if (defined $username && length $form->field("subscribe") &&
-		    IkiWiki::Plugin::notifyemail->can("subscribe")) {
-			IkiWiki::Plugin::notifyemail::subscribe($username,
-				"comment($page)");
+		if (IkiWiki::Plugin::notifyemail->can("subscribe")) {
+			my $subspec="comment($page)";
+			if (defined $username &&
+			    length $form->field("subscribe")) {
+				IkiWiki::Plugin::notifyemail::subscribe(
+					$username, $subspec);
+			}
+			elsif (length $form->field("email") &&
+			       length $form->field("anonsubscribe")) {
+				IkiWiki::Plugin::notifyemail::anonsubscribe(
+					$form->field("email"), $subspec);
+			}
 		}
 		
 		$postcomment=1;
@@ -590,7 +607,8 @@ sub editcomment ($$) {
 
 sub getavatar ($) {
 	my $user=shift;
-	
+	return undef unless defined $user;
+
 	my $avatar;
 	eval q{use Libravatar::URL};
 	if (! $@) {

IkiWiki/Plugin/notifyemail.pm

@@ -62,6 +62,19 @@ sub subscribe ($$) {
 		length $pagespec ? $pagespec." or ".$addpagespec : $addpagespec);
 }
 
+# Called by other plugins to subscribe an email to a pagespec.
+sub anonsubscribe ($$) {
+	my $email=shift;
+	my $addpagespec=shift;
+	if (IkiWiki::Plugin::passwordauth->can("anonuser")) {
+		my $user=IkiWiki::Plugin::passwordauth::anonuser($email);
+		if (! defined $user) {
+			error(gettext("Cannot subscribe your email address without logging in."));
+		}
+		subscribe($user, $addpagespec);
+	}
+}
+
 sub notify (@) {
 	my @files=@_;
 	return unless @files;
@@ -123,11 +136,20 @@ sub notify (@) {
 			if (pagetype($file) eq '_comment') {
 				$subject=gettext("comment notification:")." ".$pagedesc;
 			}
+			my $prefsurl=IkiWiki::cgiurl_abs(do => 'prefs');
+			if (IkiWiki::Plugin::passwordauth->can("anonusertoken")) {
+				my $token=IkiWiki::Plugin::passwordauth::anonusertoken($userinfo->{$user});
+				$prefsurl=IkiWiki::cgiurl_abs(
+					do => 'tokenauth',
+					name => $user,
+					token => $token,
+				) if defined $token;
+			}
 			my $template=template("notifyemail.tmpl");
 			$template->param(
 				wikiname => $config{wikiname},
 				url => $url,
-				prefsurl => IkiWiki::cgiurl_abs(do => 'prefs'),
+				prefsurl => $prefsurl,
 				showcontent => $showcontent,
 				content => $content,
 			);

IkiWiki/Plugin/passwordauth.pm

@@ -99,11 +99,71 @@ sub setpassword ($$;$) {
 
 	# Setting the password clears any passwordless login token.
 	if ($field ne 'passwordless') {
-		IkiWiki::userinfo_set($user, "cryptpasswordless", "");
 		IkiWiki::userinfo_set($user, "passwordless", "");
 	}
 }
 
+# Generates a token that can be used to log the user in.
+# This needs to be hard to guess. Generating a cgi session id will
+# make it as hard to guess as any cgi session.
+sub gentoken ($$;$) {
+	my $user=shift;
+	my $tokenfield=shift;
+	my $reversable=shift;
+
+	eval q{use CGI::Session};
+	error($@) if $@;
+	my $token = CGI::Session->new->id;
+	if (! $reversable) {
+		setpassword($user, $token, $tokenfield);
+	}
+	else {
+		IkiWiki::userinfo_set($user, $tokenfield, $token);
+	}
+	return $token;
+}
+
+# An anonymous user has no normal password, only a passwordless login
+# token. Given an email address, this sets up such a user for that email,
+# unless one already exists, and returns the username.
+sub anonuser ($) {
+	my $email=shift;
+
+	# Want a username for this email that won't overlap with any other.
+	my $user=$email;
+	$user=~s/@/_/g;
+
+	my $userinfo=IkiWiki::userinfo_retrieve();
+	if (! exists $userinfo->{$user} || ! ref $userinfo->{$user}) {
+		if (IkiWiki::userinfo_setall($user, {
+		    	'email' => $email,
+			'regdate' => time})) {
+			gentoken($user, "passwordless", 1);
+			return $user;
+		}
+		else {
+			error(gettext("Error creating account."));
+		}
+	}
+	elsif (defined anonusertoken($userinfo->{$user})) {
+		return $user;
+	}
+	else {
+		return undef;
+	}
+}
+
+sub anonusertoken ($) {
+	my $userhash=shift;
+	if (exists $userhash->{passwordless} &&
+	    length $userhash->{passwordless}) {
+		return $userhash->{passwordless};
+	}
+	else {
+		return undef;
+	}
+}
+
 sub formbuilder_setup (@) {
 	my %params=@_;
 
@@ -283,15 +343,8 @@ sub formbuilder (@) {
 				if (! length $email) {
 					error(gettext("No email address, so cannot email password reset instructions."));
 				}
-				
-				# Store a token that can be used once
-				# to log the user in. This needs to be hard
-				# to guess. Generating a cgi session id will
-				# make it as hard to guess as any cgi session.
-				eval q{use CGI::Session};
-				error($@) if $@;
-				my $token = CGI::Session->new->id;
-				setpassword($user_name, $token, "resettoken");
+
+				my $token=gentoken($user_name, "resettoken");
 				
 				my $template=template("passwordmail.tmpl");
 				$template->param(

templates/editcomment.tmpl

@@ -13,6 +13,9 @@
 <label for="url" class="block">Website:</label>
 <TMPL_VAR NAME=FIELD-URL> (optional)
 <br />
+<label for="url" class="block">Email:</label>
+<TMPL_VAR NAME=FIELD-EMAIL> <TMPL_VAR FIELD-ANONSUBSCRIBE>
+<br />
 <TMPL_ELSE>
 (You might want to <a href="<TMPL_VAR SIGNINURL>">Signin</a> first?)
 <br />