Add xml_encode function

REFERENCE.md

@@ -27,6 +27,7 @@ Thus making it directly usable with the values from facter.
 * [`extlib::read_url`](#extlibread_url): Fetch a string from a URL (should only be used with 'small' remote files).  This function should only be used with trusted/internal sources. 
 * [`extlib::resources_deep_merge`](#extlibresources_deep_merge): Deeply merge a "defaults" hash into a "resources" hash like the ones expected by `create_resources()`.
 * [`extlib::sort_by_version`](#extlibsort_by_version): A function that sorts an array of version numbers.
+* [`extlib::xml_encode`](#extlibxml_encode): Encode strings for XML files
 
 ## Functions
 
@@ -1012,3 +1013,61 @@ Data type: `Array[String]`
 
 An array of version strings you want sorted.
 
+### <a name="extlibxml_encode"></a>`extlib::xml_encode`
+
+Type: Ruby 4.x API
+
+This function can encode strings such that they can be used directly in XML files.
+It supports encoding for both XML text (CharData) or attribute values (AttValue).
+
+#### Examples
+
+##### Creating an XML file from a template
+
+```puppet
+file { '/path/to/config.xml':
+  ensure  => file,
+  content => epp(
+    'mymodule/config.xml.epp',
+    {
+      password => $password.extlib::xml_encode,
+    },
+  ),
+}
+```
+
+#### `extlib::xml_encode(String $str, Optional[Enum['text','attr']] $type)`
+
+This function can encode strings such that they can be used directly in XML files.
+It supports encoding for both XML text (CharData) or attribute values (AttValue).
+
+Returns: `String` Returns the encoded CharData or AttValue string suitable for use in XML
+
+##### Examples
+
+###### Creating an XML file from a template
+
+```puppet
+file { '/path/to/config.xml':
+  ensure  => file,
+  content => epp(
+    'mymodule/config.xml.epp',
+    {
+      password => $password.extlib::xml_encode,
+    },
+  ),
+}
+```
+
+##### `str`
+
+Data type: `String`
+
+The string to encode
+
+##### `type`
+
+Data type: `Optional[Enum['text','attr']]`
+
+Whether to encode for text or an attribute
+

lib/puppet/functions/extlib/xml_encode.rb

@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+# @summary Encode strings for XML files
+#
+# This function can encode strings such that they can be used directly in XML files.
+# It supports encoding for both XML text (CharData) or attribute values (AttValue).
+Puppet::Functions.create_function(:'extlib::xml_encode') do
+  # @param str The string to encode
+  # @param type Whether to encode for text or an attribute
+  # @return Returns the encoded CharData or AttValue string suitable for use in XML
+  # @example Creating an XML file from a template
+  #   file { '/path/to/config.xml':
+  #     ensure  => file,
+  #     content => epp(
+  #       'mymodule/config.xml.epp',
+  #       {
+  #         password => $password.extlib::xml_encode,
+  #       },
+  #     ),
+  #   }
+  dispatch :xml_encode do
+    param 'String', :str
+    optional_param "Enum['text','attr']", :type
+    return_type 'String'
+  end
+
+  def xml_encode(str, type = 'text')
+    str.encode(xml: type.to_sym)
+  end
+end

spec/functions/extlib/xml_encode_spec.rb

@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe 'extlib::xml_encode' do
+  let(:string) { 'this is "my" complicated <String>' }
+
+  it 'exists' do
+    is_expected.not_to be_nil
+  end
+
+  describe 'for XML text' do
+    let(:expected_result) { 'this is "my" complicated &lt;String&gt;' }
+
+    context 'with `type` parameter not explicity set' do
+      it { is_expected.to run.with_params(string).and_return(expected_result) }
+    end
+
+    context 'with `type` parameter set to `text`' do
+      it { is_expected.to run.with_params(string, 'text').and_return(expected_result) }
+    end
+  end
+
+  describe 'for XML attributes' do
+    it { is_expected.to run.with_params(string, 'attr').and_return('"this is &quot;my&quot; complicated &lt;String&gt;"') }
+  end
+end