From 43b2db470212bf4c5a8810535c73e92366158958 Mon Sep 17 00:00:00 2001
From: Viktor Holzwert <viktor.holzwert@uni-bamberg.de>
Date: Wed, 6 Dec 2023 13:11:56 +0100
Subject: [PATCH] WhitespaceNormalizeEnhancer: normalize whitespace and
 character encodings

---
 .../impl/WhitespaceNormalizeEnhancer.java     | 122 ++++++++++++++++++
 .../config/spring/api/metadata-enhancers.xml  |  11 ++
 2 files changed, 133 insertions(+)
 create mode 100644 dspace-api/src/main/java/org/dspace/content/enhancer/impl/WhitespaceNormalizeEnhancer.java

diff --git a/dspace-api/src/main/java/org/dspace/content/enhancer/impl/WhitespaceNormalizeEnhancer.java b/dspace-api/src/main/java/org/dspace/content/enhancer/impl/WhitespaceNormalizeEnhancer.java
new file mode 100644
index 000000000000..7ef51ee00cb8
--- /dev/null
+++ b/dspace-api/src/main/java/org/dspace/content/enhancer/impl/WhitespaceNormalizeEnhancer.java
@@ -0,0 +1,122 @@
+/**
+ * The contents of this file are subject to the license and copyright
+ * detailed in the LICENSE and NOTICE files at the root of the source
+ * tree and available online at
+ *
+ * http://www.dspace.org/license/
+ */
+package org.dspace.content.enhancer.impl;
+
+import java.text.Normalizer;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+
+import org.dspace.content.Item;
+import org.dspace.content.MetadataValue;
+import org.dspace.content.service.ItemService;
+import org.dspace.content.service.MetadataFieldService;
+import org.dspace.core.Context;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+
+public class WhitespaceNormalizeEnhancer extends RewriteEnhancer {
+    protected static final Logger LOGGER = LoggerFactory.getLogger(WhitespaceNormalizeEnhancer.class);
+    private List<String> metaDataFields;
+
+    @Autowired
+    protected ItemService itemService;
+
+    @Autowired
+    protected MetadataFieldService metadatafieldService;
+
+    protected String sourceEntityType;
+
+    public void setSourceEntityType(String sourceEntityType) {
+        this.sourceEntityType = sourceEntityType;
+    }
+
+    @Override
+    public boolean canEnhance(Context context, Item item) {
+        return sourceEntityType == null || sourceEntityType.equals(itemService.getEntityType(item));
+    }
+
+    @Override
+    public void enhance(Context context, Item item) {
+        HashMap<String, List<String>> newValues = new HashMap<>();
+        boolean modified = false;
+        for (String metaDataField : metaDataFields) {
+            List<MetadataValue> values = itemService.getMetadataByMetadataString(item, metaDataField);
+            if (values == null) {
+                continue;
+            }
+            for (MetadataValue mv : values) {
+                String text = mv.getValue();
+                String textCopy = text;
+                text = replaceSpecialSpaces(text);
+                text = replaceSpecialNewline(text);
+                text = replaceNewlineToReturnNewline(text);
+                text = removeWhitespacesBeforeReturnNewline(text);
+                text = removeZeroWidthSpaces(text);
+                text = normalizeToNFC(text);
+                if (!newValues.containsKey(metaDataField)) {
+                    newValues.put(metaDataField, new ArrayList<>());
+                }
+                if (text.equals(textCopy)) {
+                    newValues.get(metaDataField).add(textCopy);
+                } else {
+                    newValues.get(metaDataField).add(text);
+                    modified = true;
+                }
+            }
+        }
+        if (modified) {
+            updateItem(context, item, newValues);
+        }
+    }
+
+    private static String doWhileReplaceAll(String original, String regex, String replacement) {
+        String temp;
+        do {
+            temp = original;
+            original = temp.replaceAll(regex, replacement);
+        }
+        while (!temp.equals(original));
+        return original;
+    }
+
+    private static String replaceSpecialSpaces(String original) {
+        String regex = "(\\u0009|\\u00A0|\\u1680|\\u2000|\\u2001|\\u2002|\\u2003|\\u2004|\\u2005|" +
+            "\\u2006|\\u2007|\\u2008|\\u2009|\\u200A|\\u202F|\\u205F|\\u3000)+|(\\u0020){2,}";
+        return doWhileReplaceAll(original, regex, " ");
+    }
+
+    private static String replaceSpecialNewline(String original) {
+        String regex = "(\\u000B|\\u000C|\\u0085|\\u2028|\\u2029)";
+        return doWhileReplaceAll(original, regex, "\n");
+    }
+
+    private static String replaceNewlineToReturnNewline(String original) {
+        String regex = "(?<!\\u000D)\\u000A";
+        return doWhileReplaceAll(original, regex, "\r\n");
+    }
+
+    private static String removeWhitespacesBeforeReturnNewline(String original) {
+        String regex = "(\\u0020)+(?=\\u000D\\u000A)";
+        return doWhileReplaceAll(original, regex, "");
+    }
+
+    private static String removeZeroWidthSpaces(String original) {
+        String regex = "(\\u180E|\\u200B|\\u200C|\\u200D|\\u2060|\\uFEFF)+";
+        return doWhileReplaceAll(original, regex, "");
+    }
+
+    private static String normalizeToNFC(String original) {
+        return Normalizer.normalize(original, Normalizer.Form.NFC);
+    }
+
+    public void setMetaDataFields(List<String> metaDataFields) {
+        this.metaDataFields = metaDataFields;
+    }
+}
diff --git a/dspace/config/spring/api/metadata-enhancers.xml b/dspace/config/spring/api/metadata-enhancers.xml
index eb87c3202691..063be1fdf363 100644
--- a/dspace/config/spring/api/metadata-enhancers.xml
+++ b/dspace/config/spring/api/metadata-enhancers.xml
@@ -71,4 +71,15 @@
         <property name="virtualQualifier" value="orcid" />
     </bean>
 
+    <bean class="org.dspace.content.enhancer.impl.WhitespaceNormalizeEnhancer">
+        <property name="sourceEntityType" value="Publication"/>
+        <property name="metaDataFields">
+            <list>
+                <value>dc.title</value>
+                <value>dc.title.alternative</value>
+                <value>dc.description.abstract</value>
+            </list>
+        </property>
+    </bean>
+
 </beans>