Use HTML.escape to escape XML

src/util.cr

@@ -153,16 +153,6 @@ def ctime(file_path : String) : Time
   {% end %}
 end
 
-def escape_xml(str)
-  str.gsub({
-    '>'  => ">",
-    '<'  => "&lt;",
-    '"'  => "&quot;",
-    '\'' => "&apos;",
-    '&'  => "&amp;",
-  })
-end
-
 def register_mime_types
   {
     ".zip" => "application/zip",

src/views/opds/index.xml.ecr

@@ -14,7 +14,7 @@
 
   <% titles.each do |t| %>
     <entry>
-      <title><%= escape_xml(t.display_name) %></title>
+      <title><%= HTML.escape(t.display_name) %></title>
       <id>urn:mango:<%= t.id %></id>
       <link type="application/atom+xml;profile=opds-catalog;kind=navigation" rel="subsection" href="<%= base_url %>opds/book/<%= t.id %>" />
     </entry>

src/views/opds/title.xml.ecr

@@ -5,7 +5,7 @@
   <link rel="self" href="<%= base_url %>opds/book/<%= title.id %>" type="application/atom+xml;profile=opds-catalog;kind=navigation" />
   <link rel="start" href="<%= base_url %>opds/" type="application/atom+xml;profile=opds-catalog;kind=navigation" />
 
-  <title><%= escape_xml(title.display_name) %></title>
+  <title><%= HTML.escape(title.display_name) %></title>
 
   <author>
     <name>Mango</name>
@@ -14,7 +14,7 @@
 
   <% title.titles.each do |t| %>
     <entry>
-      <title><%= escape_xml(t.display_name) %></title>
+      <title><%= HTML.escape(t.display_name) %></title>
       <id>urn:mango:<%= t.id %></id>
       <link type="application/atom+xml;profile=opds-catalog;kind=navigation" rel="subsection" href="<%= base_url %>opds/book/<%= t.id %>" />
     </entry>
@@ -22,7 +22,7 @@
 
   <% title.entries.each do |e| %>
     <entry>
-      <title><%= escape_xml(e.display_name) %></title>
+      <title><%= HTML.escape(e.display_name) %></title>
       <id>urn:mango:<%= e.id %></id>
 
       <link rel="http://opds-spec.org/image" href="<%= e.cover_url %>" />