Implement #214: YAMLParser.getRawTag()

release-notes/CREDITS

@@ -54,6 +54,10 @@ Martin Winandy (@pmwmedia)
  * Reported #109: (yaml) `YAMLMapper` doesn't close output file if an error occurs
   (3.2.0)
 
+Alexander Tsvetkov (@nictas)
+ * Requested #214: (yaml) Expose custom tags via `YAMLParser.getRawTag()`
+  (3.2.0)
+
 David Xia (@davidxia)
  * Requested #276: (yaml) Support opting out of octal number interpretation (like "0444");
    add `YAMLReadFeature.PARSE_OCTAL_NUMBERS`

release-notes/VERSION

@@ -30,6 +30,9 @@ implementations)
 #109: (yaml) `YAMLMapper` doesn't close output file if an error occurs
  (reported by Martin W)
  (fix by @cowtowncoder, w/ Claude code)
+#214: (yaml) Expose custom tags via `YAMLParser.getRawTag()`
+ (requested by Alexander T)
+ (fix by @cowtowncoder, w/ Claude code)
 #264: (csv) `CsvMapper` applies alphabetic Property Order  for Java Records
  (reported by @alexpartsch)
  (fix by @cowtowncoder)

yaml/src/main/java/tools/jackson/dataformat/yaml/YAMLParser.java

@@ -1100,29 +1100,46 @@ public String getObjectId() throws JacksonException
     @Override
     public String getTypeId() throws JacksonException
     {
-        Optional<String> tagOpt;
-        if (_lastTagEvent instanceof CollectionStartEvent) {
-            tagOpt = ((CollectionStartEvent) _lastTagEvent).getTag();
-  //System.err.println("getTypeId() at "+currentToken()+", last was collection ("+_lastTagEvent.getClass().getSimpleName()+") -> "+tag);
-        } else if (_lastTagEvent instanceof ScalarEvent) {
-            tagOpt = ((ScalarEvent) _lastTagEvent).getTag();
-          //System.err.println("getTypeId() at "+currentToken()+", last was scalar -> "+tag+", scalar == "+_lastEvent);
-        } else {
-//System.err.println("getTypeId(), something else, curr token: "+currentToken());
-            return null;
-        }
-        if (tagOpt.isPresent()) {
-            String tag = tagOpt.get();
+        String tag = _currentTag().orElse(null);
+        if (tag != null) {
             // 04-Aug-2013, tatu: Looks like YAML parser's expose these in... somewhat exotic
             //   ways sometimes. So let's prepare to peel off some wrappings:
             while (tag.startsWith("!")) {
                 tag = tag.substring(1);
             }
-            return tag;
         }
-        return null;
+        return tag;
     }
-
+
+    /**
+     * Method that can be used to access the YAML tag of the current token,
+     * in its raw form: that is, without stripping leading "!" prefix(es)
+     * (unlike {@link #getTypeId()} which does strip them).
+     *<p>
+     * Note that "raw" here means raw with respect to Jackson's processing;
+     * SnakeYAML Engine may have already resolved some tag syntax (for example,
+     * verbatim tags like {@code !<tag>} are resolved to their URI content).
+     *
+     * @return Raw YAML tag of the current token, if any; {@code null} if none
+     *
+     * @since 3.2
+     */
+    public String getRawTag()
+    {
+        return _currentTag().orElse(null);
+    }
+
+    // @since 3.2
+    protected Optional<String> _currentTag()
+    {
+        if (_lastTagEvent instanceof CollectionStartEvent cse) {
+            return cse.getTag();
+        } else if (_lastTagEvent instanceof ScalarEvent se) {
+            return se.getTag();
+        }
+        return Optional.empty();
+    }
+
     /*
     /**********************************************************************
     /* Internal methods

yaml/src/test/java/tools/jackson/dataformat/yaml/type/RawTagTest.java

@@ -0,0 +1,159 @@
+package tools.jackson.dataformat.yaml.type;
+
+import org.junit.jupiter.api.Test;
+
+import tools.jackson.core.JsonToken;
+import tools.jackson.dataformat.yaml.ModuleTestBase;
+import tools.jackson.dataformat.yaml.YAMLMapper;
+import tools.jackson.dataformat.yaml.YAMLParser;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * Tests for {@link YAMLParser#getRawTag()}.
+ *
+ * @since 3.2
+ */
+public class RawTagTest extends ModuleTestBase
+{
+    private final YAMLMapper MAPPER = new YAMLMapper();
+
+    @Test
+    public void testCustomScalarTag() throws Exception
+    {
+        final String YAML = "---\npassword: !sensitive Abcd1234\n";
+        try (YAMLParser p = (YAMLParser) MAPPER.createParser(YAML)) {
+            assertToken(JsonToken.START_OBJECT, p.nextToken());
+            assertNull(p.getRawTag());
+
+            assertToken(JsonToken.PROPERTY_NAME, p.nextToken());
+            assertEquals("password", p.currentName());
+
+            assertToken(JsonToken.VALUE_STRING, p.nextToken());
+            assertEquals("Abcd1234", p.getText());
+            assertEquals("!sensitive", p.getRawTag());
+            // getTypeId() should strip the "!" prefix
+            assertEquals("sensitive", p.getTypeId());
+
+            assertToken(JsonToken.END_OBJECT, p.nextToken());
+            assertNull(p.getRawTag());
+        }
+    }
+
+    @Test
+    public void testVerbatimTag() throws Exception
+    {
+        // Verbatim tag !<...> is resolved by SnakeYAML Engine into the URI content
+        final String YAML = "--- !<impl>\na: 13\n";
+        try (YAMLParser p = (YAMLParser) MAPPER.createParser(YAML)) {
+            assertToken(JsonToken.START_OBJECT, p.nextToken());
+            assertEquals("impl", p.getRawTag());
+
+            assertToken(JsonToken.PROPERTY_NAME, p.nextToken());
+            assertToken(JsonToken.VALUE_NUMBER_INT, p.nextToken());
+            assertEquals(13, p.getIntValue());
+
+            assertToken(JsonToken.END_OBJECT, p.nextToken());
+        }
+    }
+
+    @Test
+    public void testLocalTag() throws Exception
+    {
+        // Local tag !impl keeps the "!" prefix
+        final String YAML = "--- !impl\na: 13\n";
+        try (YAMLParser p = (YAMLParser) MAPPER.createParser(YAML)) {
+            assertToken(JsonToken.START_OBJECT, p.nextToken());
+            assertEquals("!impl", p.getRawTag());
+            // getTypeId() strips the "!" prefix
+            assertEquals("impl", p.getTypeId());
+
+            assertToken(JsonToken.PROPERTY_NAME, p.nextToken());
+            assertToken(JsonToken.VALUE_NUMBER_INT, p.nextToken());
+            assertEquals(13, p.getIntValue());
+
+            assertToken(JsonToken.END_OBJECT, p.nextToken());
+        }
+    }
+
+    @Test
+    public void testNoTag() throws Exception
+    {
+        final String YAML = "---\nkey: value\n";
+        try (YAMLParser p = (YAMLParser) MAPPER.createParser(YAML)) {
+            assertToken(JsonToken.START_OBJECT, p.nextToken());
+            assertNull(p.getRawTag());
+
+            assertToken(JsonToken.PROPERTY_NAME, p.nextToken());
+            assertToken(JsonToken.VALUE_STRING, p.nextToken());
+            assertEquals("value", p.getText());
+            assertNull(p.getRawTag());
+
+            assertToken(JsonToken.END_OBJECT, p.nextToken());
+        }
+    }
+
+    @Test
+    public void testSequenceTag() throws Exception
+    {
+        final String YAML = "--- !mylist\n- a\n- b\n";
+        try (YAMLParser p = (YAMLParser) MAPPER.createParser(YAML)) {
+            assertToken(JsonToken.START_ARRAY, p.nextToken());
+            assertEquals("!mylist", p.getRawTag());
+
+            assertToken(JsonToken.VALUE_STRING, p.nextToken());
+            assertEquals("a", p.getText());
+            assertNull(p.getRawTag());
+
+            assertToken(JsonToken.VALUE_STRING, p.nextToken());
+            assertEquals("b", p.getText());
+            assertNull(p.getRawTag());
+
+            assertToken(JsonToken.END_ARRAY, p.nextToken());
+        }
+    }
+
+    @Test
+    public void testSecondaryTagHandle() throws Exception
+    {
+        // "!!" is the secondary tag handle, resolved by SnakeYAML Engine
+        // to the "tag:yaml.org,2002:" prefix
+        final String YAML = "---\nvalue: !!str 123\n";
+        try (YAMLParser p = (YAMLParser) MAPPER.createParser(YAML)) {
+            assertToken(JsonToken.START_OBJECT, p.nextToken());
+
+            assertToken(JsonToken.PROPERTY_NAME, p.nextToken());
+            assertToken(JsonToken.VALUE_STRING, p.nextToken());
+            assertEquals("123", p.getText());
+            // Raw tag includes the resolved "tag:yaml.org,2002:" prefix
+            assertEquals("tag:yaml.org,2002:str", p.getRawTag());
+            // getTypeId() strips "!" but this tag has none, so same value
+            assertEquals("tag:yaml.org,2002:str", p.getTypeId());
+
+            assertToken(JsonToken.END_OBJECT, p.nextToken());
+        }
+    }
+
+    @Test
+    public void testMultipleCustomTags() throws Exception
+    {
+        final String YAML = "---\nuser: !public someone\npass: !sensitive Abcd1234\n";
+        try (YAMLParser p = (YAMLParser) MAPPER.createParser(YAML)) {
+            assertToken(JsonToken.START_OBJECT, p.nextToken());
+
+            assertToken(JsonToken.PROPERTY_NAME, p.nextToken());
+            assertEquals("user", p.currentName());
+            assertToken(JsonToken.VALUE_STRING, p.nextToken());
+            assertEquals("someone", p.getText());
+            assertEquals("!public", p.getRawTag());
+
+            assertToken(JsonToken.PROPERTY_NAME, p.nextToken());
+            assertEquals("pass", p.currentName());
+            assertToken(JsonToken.VALUE_STRING, p.nextToken());
+            assertEquals("Abcd1234", p.getText());
+            assertEquals("!sensitive", p.getRawTag());
+
+            assertToken(JsonToken.END_OBJECT, p.nextToken());
+        }
+    }
+}