Add pom versioning

src/main/java/dev/kruhlmann/imgfloat/service/VersionService.java

@@ -5,6 +5,10 @@ import org.slf4j.LoggerFactory;
 import org.springframework.stereotype.Component;
 
 import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
 
 @Component
 public class VersionService {
@@ -31,6 +35,11 @@ public class VersionService {
             return pomVersion;
         }
 
+        String pomXmlVersion = getPomXmlVersion();
+        if (pomXmlVersion != null && !pomXmlVersion.isBlank()) {
+            return pomXmlVersion;
+        }
+
         return "unknown";
     }
 
@@ -64,4 +73,60 @@ public class VersionService {
         }
         return null;
     }
+
+    private String getPomXmlVersion() {
+        // Attempt to load pom.xml from the classpath (available when running from sources)
+        InputStream classpathPom = getClass().getClassLoader().getResourceAsStream("pom.xml");
+        if (classpathPom != null) {
+            try {
+                String version = extractVersionFromPom(classpathPom);
+                if (version != null) {
+                    return version;
+                }
+            } finally {
+                try {
+                    classpathPom.close();
+                } catch (IOException e) {
+                    LOG.warn("Unable to close pom.xml stream from classpath", e);
+                }
+            }
+        }
+
+        // Fallback to reading pom.xml from the filesystem root (common during development)
+        Path pomPath = Paths.get("pom.xml");
+        if (Files.exists(pomPath) && Files.isRegularFile(pomPath)) {
+            try (InputStream filePom = Files.newInputStream(pomPath)) {
+                return extractVersionFromPom(filePom);
+            } catch (IOException e) {
+                LOG.warn("Unable to read pom.xml from filesystem", e);
+            }
+        }
+
+        return null;
+    }
+
+    private String extractVersionFromPom(InputStream pomInputStream) {
+        if (pomInputStream == null) {
+            return null;
+        }
+        try {
+            var documentBuilderFactory = javax.xml.parsers.DocumentBuilderFactory.newInstance();
+            documentBuilderFactory.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false);
+            documentBuilderFactory.setFeature("http://xml.org/sax/features/external-general-entities", false);
+            documentBuilderFactory.setFeature("http://xml.org/sax/features/external-parameter-entities", false);
+
+            var documentBuilder = documentBuilderFactory.newDocumentBuilder();
+            var document = documentBuilder.parse(pomInputStream);
+            var versionNodes = document.getElementsByTagName("version");
+            if (versionNodes.getLength() > 0) {
+                var version = versionNodes.item(0).getTextContent();
+                if (version != null && !version.isBlank()) {
+                    return version.trim();
+                }
+            }
+        } catch (Exception e) {
+            LOG.warn("Unable to parse version from pom.xml", e);
+        }
+        return null;
+    }
 }