Add new GA4 google analytics script into pages

cgi-bin/DW/PageStats/GoogleAnalytics4.pm

@@ -0,0 +1,68 @@
+#!/usr/bin/perl
+#
+# DW::PageStats::GoogleAnalytics4
+#
+# LJ::PageStats module for Google Analytics
+#
+# Authors:
+#      Andrea Nall <anall@andreanall.com>
+#
+# Copyright (c) 2009 by Dreamwidth Studios, LLC.
+#
+# This program is free software; you may redistribute it and/or modify it under
+# the same terms as Perl itself.  For a copy of the license, please reference
+# 'perldoc perlartistic' or 'perldoc perlgpl'.
+#
+package DW::PageStats::GoogleAnalytics4;
+use base 'LJ::PageStats';
+use strict;
+
+sub _render_head {
+    my ($self) = @_;
+    return '' unless $self->should_do_pagestats;
+
+    my $ctx = $self->get_context;
+
+    my $code;
+    if ( $ctx eq 'app' ) {
+        $code = $LJ::SITE_PAGESTAT_CONFIG{ga4_analytics};
+    }
+    elsif ( $ctx eq 'journal' ) {
+        $code = LJ::get_active_journal()->ga4_analytics;
+
+        # the ejs call isn't strictly necessary but catches any
+        # dodgy analytics codes which may have been stored before
+        # validation was implemented.
+        $code = LJ::ejs($code);
+    }
+
+    return qq{<!-- Global site tag (gtag.js) - Google Analytics -->
+<script async src="https://www.googletagmanager.com/gtag/js?id=$code"></script>
+<script>
+  window.dataLayer = window.dataLayer || [];
+  function gtag(){dataLayer.push(arguments);}
+  gtag('js', new Date());
+
+  gtag('config', '$code');
+</script>
+};
+}
+
+
+sub should_render {
+    my ($self) = @_;
+
+    my $ctx = $self->get_context;
+    return 0 unless $ctx && $ctx =~ /^(app|journal)$/;
+
+    if ( $ctx eq 'app' ) {
+        return 1 if defined $LJ::SITE_PAGESTAT_CONFIG{ga4_analytics};
+    }
+    elsif ( $ctx eq 'journal' ) {
+        my $u = LJ::get_active_journal();
+        return $u && $u->can_use_google_analytics && $u->ga4_analytics ? 1 : 0;
+    }
+    return 0;
+}
+
+1;