Fix UTF8 file encoding for views export

Today's problem - there are two sites with Drupal 7, they have views export modules and a csv file is generated, but at the same time on one site the file encoding is utf-8 on the second utf-8 bom. At the same time, the hosting settings are the same, the php versions are the same, the views export settings are also the same. A possible solution is to apply a patch found on drupal.org, which adds a bom checkbox for encoding to the settings.

Below is the text of the patch

diff --git a/plugins/views_data_export_plugin_style_export_csv.inc b/plugins/views_dðÊÉíU  ðÊÉíU                  ЛÉÉíU           ™ÉÉíU  XÊÉíU          ÊÉíU   @      ÊÉíU          rt_plugin_style_export_csv.inc
+++ b/plugins/views_data_export_plugin_style_export_csv.inc
@@ -56,6 +56,10 @@ class views_data_export_plugin_style_export_csv extends views_data_export_plugin
       'default' => '',
       'translatable' => FALSE,
     );
+    $options['utf8_bom'] = array(
+      'default' => '0',
+      'translatable' => FALSE,
+    );
 
     return $options;
   }
@@ -132,5 +136,11 @@ class views_data_export_plugin_style_export_csv extends views_data_export_plugin
       '#description' => t('Optionally specify a character conversion that some CSV file readers need. Use "utf8_decode" for ISO-8859-1 via <a href="@utf8_decode">utf8_decode PHP function</a>, other values will be passed <a href="@iconv">iconv</a> (this requires the iconv PHP extension), empty or illegal values will leave the output as UTF-8.',
         array('@iconv' => 'http://www.php.net/manual/en/function.iconv.php', '@utf8_decode' => 'http://www.php.net/manual/en/function.utf8-decode.php')),
     );
+    $form['utf8_bom'] = array(
+      '#type' => 'checkbox',
+      '#default_value' => !empty($this->options['utf8_bom']),
+      '#title' => t('Include unicode signature (<a href="@bom" target="_blank">BOM</a>).',
+        array('@bom' => 'https://www.w3.org/International/questions/qa-byte-order-mark')),
+    );
   }
 }
diff --git a/tests/csv_export.test b/tests/csv_export.test
index 148ef8f..285ec0e 100644
--- a/tests/csv_export.test
+++ b/tests/csv_export.test
@@ -282,4 +282,37 @@ EOT;
     $this->executeAndCompareGivenView($view, $expected, $message, $style_options);
   }
 
+  /**
+   * Test to ensure that UTF-8 BOM works.
+   */
+  protected function testUtf8Bom() {
+    $view = $this->getBasicExportView();
+
+    // Test on Korean characters. '大韓民國' means "Republic of Korea"
+    // @see https://en.wikipedia.org/wiki/South_Korea
+    db_update('views_test')
+      ->fields(array('name' => '大韓民國'))
+      ->condition('name', 'John')
+      ->execute();
+
+    $style_options = array(
+      'utf8_bom' => TRUE,
+    );
+
+    // BOM.
+    $expected = "\xEF\xBB\xBF";
+    // Content.
+    $expected .= '"ID","Name","Age"
+"1","大韓民國","25"
+"2","George","27"
+"3","Ringo","28"
+"4","Paul","26"
+"5","Meredith","30"';
+
+    $message = 'Unicode signature (BOM) added correctly.';
+
+    $this->executeAndCompareGivenView($view, $expected, $message, $style_options);
+
+  }
+
 }
diff --git a/theme/views-data-export-csv-header.tpl.php b/theme/views-data-export-csv-header.tpl.php
index e40a1bf..db92b2f 100644
--- a/theme/views-data-export-csv-header.tpl.php
+++ b/theme/views-data-export-csv-header.tpl.php
@@ -1,5 +1,8 @@
 <?php
 
+// Begin file with UTF-8 BOM, if needed.
+print $optional_utf8_bom;
+
 // Print out header row, if option was selected.
 if ($options['header']) {
   print implode($separator, $header) . "\r\n";
diff --git a/theme/views_data_export.theme.inc b/theme/views_data_export.theme.inc
index 4e31fb0..97ac819 100644
--- a/theme/views_data_export.theme.inc
+++ b/theme/views_data_export.theme.inc
@@ -102,6 +102,15 @@ function template_preprocess_views_data_export_csv_header(&$vars) {
     $wrap = '';
     $replace_value = '';
   }
+  // Add UTF-8 BOM character, if needed.
+  if (!empty($vars['options']['utf8_bom']) && empty($vars['options']['encoding'])) {
+    // Assume UTF-8 if no encoding configured.
+    $vars['optional_utf8_bom'] = "\xEF\xBB\xBF";
+  }
+  else {
+    // Do not add UTF-8 BOM if views with character encoding conversion.
+    $vars['optional_utf8_bom'] = '';
+  }
 
   // Format header values.
   foreach ($vars['header'] as $key => $value) {