w3c · rdeltour · Dec 1, 2022 · Nov 14, 2021
diff --git a/src/main/java/com/adobe/epubcheck/messages/DefaultSeverities.java b/src/main/java/com/adobe/epubcheck/messages/DefaultSeverities.java
@@ -273,6 +273,7 @@ private void initialize()
     severities.put(MessageId.OPF_089, Severity.ERROR);
     severities.put(MessageId.OPF_090, Severity.USAGE);
     severities.put(MessageId.OPF_091, Severity.ERROR);
+    severities.put(MessageId.OPF_092, Severity.ERROR);
 
     // PKG
     severities.put(MessageId.PKG_001, Severity.WARNING);

diff --git a/src/main/java/com/adobe/epubcheck/messages/MessageId.java b/src/main/java/com/adobe/epubcheck/messages/MessageId.java
@@ -267,6 +267,7 @@ public enum MessageId implements Comparable<MessageId>
   OPF_089("OPF-089"),
   OPF_090("OPF-090"),
   OPF_091("OPF-091"),
+  OPF_092("OPF-092"),
 
   // Messages relating to the entire package
   PKG_001("PKG-001"),

diff --git a/src/main/java/com/adobe/epubcheck/opf/OPFHandler30.java b/src/main/java/com/adobe/epubcheck/opf/OPFHandler30.java
@@ -50,7 +50,9 @@
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.util.Deque;
+import java.util.IllformedLocaleException;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
 
@@ -166,6 +168,12 @@ public void startElement()
 
     XMLElement e = parser.getCurrentElement();
     String name = e.getName();
+
+    // Check global attributes
+    String xmllang = e.getAttributeNS(EpubConstants.XmlNamespaceUri, "lang");
+    if (xmllang != null && !xmllang.isEmpty()) {
+      checkLanguageTag(xmllang);
+    }
 
     if (EpubConstants.OpfNamespaceUri.equals(e.getNamespace()))
     {
@@ -469,6 +477,11 @@ private void processLink(XMLElement e)
           .refines(e.getAttribute("refines")).build();
       linkedResourcesBuilders.peekFirst().add(resource);
     }
+
+    String hreflang = e.getAttribute("hreflang");
+    if (hreflang != null && !hreflang.isEmpty()) {
+      checkLanguageTag(hreflang);
+    }
   }
 
   private void processItemrefProperties(OPFItem.Builder builder, String property)
@@ -566,11 +579,22 @@ private void processDCElem(XMLElement e)
   {
     // get the property
     Optional<Property> prop = DCMESVocab.VOCAB.lookup(e.getName());
+    // Add to the metadata model builder
     if (prop.isPresent() && !metadataBuilders.isEmpty())
     {
       metadataBuilders.peekFirst().meta(e.getAttribute("id"), prop.get(),
           (String) e.getPrivateData(), null);
     }
+    // Check that dc:language is well-formed 
+    if ("language".equals(e.getName()))
+    {
+      String language = (String) e.getPrivateData();
+      // Empty dc:language is checked by the schema
+      if (language != null && !language.trim().isEmpty())
+      {
+        checkLanguageTag(language.trim());
+      }
+    }
   }
 
   private void processItemsInIndexCollection(ResourceCollection collection)
@@ -592,6 +616,19 @@ private void processItemsInIndexCollection(ResourceCollection collection)
       }
     }
   }
+
+  private void checkLanguageTag(String language)
+  {
+    try
+    {
+      new Locale.Builder().setLanguageTag(language);
+    } catch (IllformedLocaleException exception)
+    {
+      report.message(MessageId.OPF_092,
+          EPUBLocation.create(path, parser.getLineNumber(), parser.getColumnNumber()), language,
+          exception.getMessage());
+    }
+  }
 
   protected void reportMetadata()
   {

diff --git a/src/main/resources/com/adobe/epubcheck/messages/MessageBundle.properties b/src/main/resources/com/adobe/epubcheck/messages/MessageBundle.properties
@@ -282,6 +282,7 @@ OPF_088=Unrecognized epub:type value "%1$s".
 OPF_089=The "alternate" link rel keyword cannot be paired with other keywords.
 OPF_090=It is encouraged to use MIME media type "%1$s" instead of "%2$s".
 OPF_091=The item href URL must not have a fragment identifier.
+OPF_092=Language tag "%1$s" is not well-formed: %2$s
 
 #Package
 PKG_001=Validating the EPUB against version %1$s but detected version %2$s.

diff --git a/src/main/resources/com/adobe/epubcheck/schema/30/package-30.rnc b/src/main/resources/com/adobe/epubcheck/schema/30/package-30.rnc
@@ -36,7 +36,7 @@
 
    opf.dc.identifier = element dc:identifier { opf.id.attr? & datatype.string.nonempty } 
    opf.dc.title = element dc:title { opf.dc.attlist & datatype.string.nonempty }
-   opf.dc.language = element dc:language { opf.id.attr? & datatype.languagecode }
+   opf.dc.language = element dc:language { opf.id.attr? & datatype.string.nonempty }
    opf.dc.date = element dc:date { opf.id.attr? & datatype.string.nonempty }
    opf.dc.source = element dc:source { opf.dc.attlist & datatype.string.nonempty }
    opf.dc.type = element dc:type { opf.id.attr? & datatype.string.nonempty }
@@ -129,5 +129,5 @@
    opf.href.attr = attribute href { datatype.URI }
    opf.id.attr = attribute id { datatype.ID }
    opf.i18n.attrs = opf.xml.lang.attr? & opf.dir.attr?
-   opf.xml.lang.attr = attribute xml:lang { "" | datatype.languagecode }
+   opf.xml.lang.attr = attribute xml:lang { "" | datatype.string.nonempty }
    opf.dir.attr = attribute dir { 'ltr' | 'rtl' }
diff --git a/src/test/resources/epub3/files/package-document/attr-lang-not-well-formed-error.opf b/src/test/resources/epub3/files/package-document/attr-lang-not-well-formed-error.opf
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<package xmlns="http://www.idpf.org/2007/opf" version="3.0" unique-identifier="uid"
+    xmlns:dc="http://purl.org/dc/elements/1.1/">
+    <metadata>
+        <dc:title>Title</dc:title>
+        <dc:language>en</dc:language>
+        <dc:identifier id="uid">NOID</dc:identifier>
+        <meta property="dcterms:modified">2019-01-01T12:00:00Z</meta>
+        <dc:creator xml:lang="a-value">Jane Doe</dc:creator>
+    </metadata>
+    <manifest>
+        <item id="t001" href="contents.xhtml" properties="nav" media-type="application/xhtml+xml"/>
+    </manifest>
+    <spine>
+        <itemref idref="t001"/>
+    </spine>
+</package>
diff --git a/src/test/resources/epub3/files/package-document/attr-lang-whitespace-error.opf b/src/test/resources/epub3/files/package-document/attr-lang-whitespace-error.opf
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<package xmlns="http://www.idpf.org/2007/opf" version="3.0" unique-identifier="uid"
+    xmlns:dc="http://purl.org/dc/elements/1.1/">
+    <metadata>
+        <dc:title>Title</dc:title>
+        <dc:language>en</dc:language>
+        <dc:identifier id="uid">NOID</dc:identifier>
+        <meta property="dcterms:modified">2019-01-01T12:00:00Z</meta>
+        <dc:creator xml:lang="  en  ">Jane Doe</dc:creator>
+    </metadata>
+    <manifest>
+        <item id="t001" href="contents.xhtml" properties="nav" media-type="application/xhtml+xml"/>
+    </manifest>
+    <spine>
+        <itemref idref="t001"/>
+    </spine>
+</package>
diff --git a/src/test/resources/epub3/files/package-document/link-hreflang-not-well-formed-error.opf b/src/test/resources/epub3/files/package-document/link-hreflang-not-well-formed-error.opf
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<package xmlns="http://www.idpf.org/2007/opf" version="3.0" unique-identifier="uid"
+    xmlns:dc="http://purl.org/dc/elements/1.1/">
+    <metadata>
+        <dc:title>Title</dc:title>
+        <dc:language>en</dc:language>
+        <dc:identifier id="uid">NOID</dc:identifier>
+        <meta property="dcterms:modified">2019-01-01T12:00:00Z</meta>
+        <link hreflang="a-value" rel="alternate" href="https://example.org/package.json" media-type="application/json-ld"/>
+    </metadata>
+    <manifest>
+        <item id="t001" href="contents.xhtml" properties="nav" media-type="application/xhtml+xml"/>
+    </manifest>
+    <spine>
+        <itemref idref="t001"/>
+    </spine>
+</package>
diff --git a/src/test/resources/epub3/files/package-document/link-hreflang-whitespace-error.opf b/src/test/resources/epub3/files/package-document/link-hreflang-whitespace-error.opf
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<package xmlns="http://www.idpf.org/2007/opf" version="3.0" unique-identifier="uid"
+    xmlns:dc="http://purl.org/dc/elements/1.1/">
+    <metadata>
+        <dc:title>Title</dc:title>
+        <dc:language>en</dc:language>
+        <dc:identifier id="uid">NOID</dc:identifier>
+        <meta property="dcterms:modified">2019-01-01T12:00:00Z</meta>
+        <link hreflang=" en " rel="alternate" href="https://example.org/package.json" media-type="application/json-ld"/>
+    </metadata>
+    <manifest>
+        <item id="t001" href="contents.xhtml" properties="nav" media-type="application/xhtml+xml"/>
+    </manifest>
+    <spine>
+        <itemref idref="t001"/>
+    </spine>
+</package>
diff --git a/src/test/resources/epub3/files/package-document/metadata-language-empty-error.opf b/src/test/resources/epub3/files/package-document/metadata-language-empty-error.opf
@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<package xmlns="http://www.idpf.org/2007/opf" version="3.0" unique-identifier="uid"
+  xmlns:dc="http://purl.org/dc/elements/1.1/">
+  <metadata>
+    <dc:title>Title</dc:title>
+    <dc:language>    </dc:language>
+    <dc:identifier id="uid">NOID</dc:identifier>
+    <meta property="dcterms:modified">2019-01-01T12:00:00Z</meta>
+  </metadata>
+  <manifest>
+    <item id="t001" href="contents.xhtml" properties="nav" media-type="application/xhtml+xml"/>
+  </manifest>
+  <spine>
+    <itemref idref="t001"/>
+  </spine>
+</package>
diff --git a/src/test/resources/epub3/files/package-document/metadata-language-not-well-formed-error.opf b/src/test/resources/epub3/files/package-document/metadata-language-not-well-formed-error.opf
@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<package xmlns="http://www.idpf.org/2007/opf" version="3.0" unique-identifier="uid"
+  xmlns:dc="http://purl.org/dc/elements/1.1/">
+  <metadata>
+    <dc:title>Title</dc:title>
+    <dc:language>a-value</dc:language>
+    <dc:identifier id="uid">NOID</dc:identifier>
+    <meta property="dcterms:modified">2019-01-01T12:00:00Z</meta>
+  </metadata>
+  <manifest>
+    <item id="t001" href="contents.xhtml" properties="nav" media-type="application/xhtml+xml"/>
+  </manifest>
+  <spine>
+    <itemref idref="t001"/>
+  </spine>
+</package>
diff --git a/src/test/resources/epub3/package-document.feature b/src/test/resources/epub3/package-document.feature
@@ -90,6 +90,16 @@ Feature: EPUB 3 ▸ Packages ▸ Package Document Checks
   Scenario: the 'xml:lang' attribute can be empty
     When checking file 'attr-lang-empty-valid.opf'
     Then no other errors or warnings are reported
+
+  Scenario: the 'xml:lang' language tag must not have leading/trailing whitespace   
+    When checking file 'attr-lang-whitespace-error.opf'
+    Then error OPF-092 is reported
+    And no other errors or warnings are reported
+
+  Scenario: the 'xml:lang' language tag must be well-formed   
+    When checking file 'attr-lang-not-well-formed-error.opf'
+    Then error OPF-092 is reported
+    And no other errors or warnings are reported
 
   ## 3.4.3 Metadata
   ### 3.4.3 The metadata element
@@ -106,7 +116,18 @@ Feature: EPUB 3 ▸ Packages ▸ Package Document Checks
     When checking file 'metadata-identifier-uuid-invalid-warning.opf'
     Then warning OPF-085 is reported
     And no other errors or warnings are reported
-
+
+ Scenario: 'dc:language' must not be empty  
+    When checking file 'metadata-language-empty-error.opf'
+    Then error RSC-005 is reported
+    And the message contains "must be a string with length at least 1"
+    And no other errors or warnings are reported
+
+ Scenario: 'dc:language' must be well-formed  
+    When checking file 'metadata-language-not-well-formed-error.opf'
+    Then error OPF-092 is reported
+    And no other errors or warnings are reported
+
   Scenario: 'dc:modified' must be defined 
     When checking file 'metadata-modified-missing-error.opf'
     Then error RSC-005 is reported
@@ -245,6 +266,16 @@ Feature: EPUB 3 ▸ Packages ▸ Package Document Checks
   Scenario: the 'link' 'hreflang' attribute can be empty
     When checking file 'link-hreflang-empty-valid.opf'
     Then no other errors or warnings are reported
+
+  Scenario: the 'link' 'hreflang' language tag must not have leading/trailing whitespace   
+    When checking file 'link-hreflang-whitespace-error.opf'
+    Then error OPF-092 is reported
+    And no other errors or warnings are reported
+
+  Scenario: the 'link' 'hreflang' language tag must be well-formed   
+    When checking file 'link-hreflang-not-well-formed-error.opf'
+    Then error OPF-092 is reported
+    And no other errors or warnings are reported
 
   ### 3.4.4 Manifest