Add /info page

This is only for users logged in, with granted "admin" privileges
(is_admin column in users table in database, by default false for
everybody, has to be manually changed in database).

Info page shows loaded modules, perl version and paths to used perl
interpreter and top level of explain.depesz.com application.

lib/Explain.pm

@@ -71,6 +71,9 @@ sub startup {
     # route: 'help'
     $routes->route( '/help' )->to( 'controller#help' )->name( 'help' );
 
+    # route: 'info'
+    $routes->route( '/info' )->to( 'controller#info' )->name( 'info' );
+
     return;
 }
 

lib/Explain/Controller.pm

@@ -7,10 +7,12 @@ use English -no_match_vars;
 use Pg::Explain;
 use Encode;
 use Email::Valid;
+use Config;
 
 sub logout {
     my $self = shift;
     delete $self->session->{ 'user' };
+    delete $self->session->{ 'admin' };
     $self->redirect_to( 'new-explain' );
 }
 
@@ -149,9 +151,10 @@ sub login {
         return;
     }
 
-    if ( $self->database->user_login( $username, $password ) ) {
+    if ( my $user = $self->database->user_login( $username, $password ) ) {
         $self->flash( 'message' => 'User logged in.' );
         $self->session( 'user' => $username );
+        $self->session( 'admin' => $user->{ 'admin' } );
         $self->redirect_to( 'new-explain' );
     }
     $self->stash->{ 'message' } = 'Bad username or password.';
@@ -357,6 +360,30 @@ sub contact {
     $self->redirect_to( 'contact' );
 }
 
+sub info {
+    my $self = shift;
+    $self->redirect_to( 'new-explain' ) unless $self->session->{ 'user' };
+    $self->redirect_to( 'new-explain' ) unless $self->session->{ 'admin' };
+
+    my @versions = ();
+    for my $module ( sort keys %INC ) {
+        next if $module =~ m{^\.?/};
+        $module =~ s/\.pm$//;
+        $module =~ s#/#::#g;
+        push @versions, {
+            'module' => $module,
+            'version' => $module->VERSION,
+        };
+    }
+    $self->stash( 'modules' => \@versions );
+    $self->stash( 'perl' => {
+            'version' => $PERL_VERSION,
+            'binary'  => $Config{'perlpath'} . $Config{'_exe'},
+        }
+    );
+
+}
+
 sub help {
 
     # direct to template

lib/Explain/Plugin/Database.pm

@@ -75,7 +75,7 @@ sub user_login {
     my ( $username, $password ) = @_;
 
     my @row = $self->dbh->selectrow_array(
-        'SELECT password FROM users where username = ?',
+        'SELECT password, is_admin FROM users where username = ?',
         undef,
         $username,
     );
@@ -83,7 +83,7 @@ sub user_login {
     my $crypted = crypt( $password, $row[ 0 ] );
 
     return if $crypted ne $row[ 0 ];
-    return 1;
+    return { 'admin' => $row[1] };
 }
 
 sub user_change_password {

sql/patch-003.sql

@@ -0,0 +1 @@
+ALTER TABLE users ADD COLUMN is_admin BOOL DEFAULT false;

templates/controller/info.html.ep

@@ -0,0 +1,23 @@
+% layout 'default';
+
+% my $title = 'System information';
+% title $title;
+
+<h1><%= $title =%></h1>
+
+<ul>
+    <li>Perl version: <%= $perl->{'version'} %></li>
+    <li>Perl binary: <%= $perl->{'binary'} %></li>
+    <li>App home: <%= app()->home() %>
+    <li>Loaded modules:
+    <ul>
+% for my $item ( @{ $modules } ) {
+        <li><%= $item->{'module'} %>
+% if ( $item->{'version'} ) {
+        version <%= $item->{'version'} %>
+% }
+        </li>
+% }
+    </ul>
+    </li>
+</ul>