A quick implementation of using DataCite REST API for retrieving

DOI metadata from DataCite. This is to address an apparent issue
with UTF8 characters when relying on the MDS API used traditionally.
(#12070)

Author: landreev

src/main/java/edu/harvard/iq/dataverse/pidproviders/doi/datacite/DOIDataCiteRegisterService.java

@@ -46,6 +46,10 @@ public DOIDataCiteRegisterService(String url, String username, String password)
             client = new DataCiteRESTfullClient(url, username, password);
     }
 
+    public DOIDataCiteRegisterService(String url, String restApiUrl, String username, String password) {
+            client = new DataCiteRESTfullClient(url, restApiUrl, username, password);
+    }
+
     /**
      * This "reserveIdentifier" method is heavily based on the
      * "registerIdentifier" method below but doesn't, this one doesn't doesn't
@@ -80,13 +84,14 @@ public String registerIdentifier(String identifier, Map<String, String> metadata
 
     public String reRegisterIdentifier(String identifier, Map<String, String> metadata, DvObject dvObject) throws IOException {
         String retString = "";
-        String numericIdentifier = identifier.substring(identifier.indexOf(":") + 1);
+        // "bare identifier" is the canonical pid with the "doi:" prefix stripped
+        String bareIdentifier = identifier.substring(identifier.indexOf(":") + 1);
         String xmlMetadata = getMetadataFromDvObject(identifier, metadata, dvObject);
         String target = metadata.get("_target");
         String currentMetadata = null;
         boolean hasDifferences = false;
         try {
-            currentMetadata = client.getMetadata(numericIdentifier);
+            currentMetadata = client.getMetadataViaRestApi(bareIdentifier);
             Diff myDiff = DiffBuilder.compare(xmlMetadata).withTest(currentMetadata).ignoreWhitespace().checkForSimilar()
                     .build();
             hasDifferences = myDiff.hasDifferences();
@@ -96,7 +101,7 @@ public String reRegisterIdentifier(String identifier, Map<String, String> metada
                 }
             }
         } catch (RuntimeException e) {
-            logger.log(Level.INFO, "DOI " + numericIdentifier + " not registered with DataCite, registering now.");
+            logger.log(Level.INFO, "DOI " + bareIdentifier + " not registered with DataCite, registering now.");
             hasDifferences = true;
         }
 
@@ -106,13 +111,13 @@ public String reRegisterIdentifier(String identifier, Map<String, String> metada
         String currentUrl = null;
         try {
             //May get a 204 if the DOI is still draft
-            currentUrl = client.getUrl(numericIdentifier);
+            currentUrl = client.getUrl(bareIdentifier);
         } catch (RuntimeException ex) {
-            logger.fine("Error getting Url for " + numericIdentifier + ": " + ex.getMessage());
+            logger.fine("Error getting Url for " + bareIdentifier + ": " + ex.getMessage());
         }
         if (!target.equals(currentUrl)) {
             logger.info("Updating target URL to " +  target);
-            client.postUrl(numericIdentifier, target);
+            client.postUrl(bareIdentifier, target);
             retString = retString + "url:\\r" + target;
 
         }

src/main/java/edu/harvard/iq/dataverse/pidproviders/doi/datacite/DataCiteDOIProvider.java

@@ -59,7 +59,7 @@ public DataCiteDOIProvider(String id, String label, String providerAuthority, St
         this.apiUrl = apiUrl;
         this.username = username;
         this.password = password;
-        doiDataCiteRegisterService = new DOIDataCiteRegisterService(mdsUrl, username, password);
+        doiDataCiteRegisterService = new DOIDataCiteRegisterService(mdsUrl, apiUrl, username, password);
     }
 
     @Override
@@ -349,7 +349,7 @@ public boolean updateIdentifier(DvObject dvObject) {
                 logger.info(identifier + "updated: " + updated );
                 return true;
             } else {
-                logger.info("No updated needed for " + identifier);
+                logger.info("No update needed for " + identifier);
                 return false; //No update needed
             }
         } catch (Exception e) {

src/main/java/edu/harvard/iq/dataverse/pidproviders/doi/datacite/DataCiteRESTfullClient.java

@@ -8,6 +8,7 @@
 
 import java.io.Closeable;
 import java.io.IOException;
+import java.util.Base64;
 
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -26,10 +27,9 @@
 import org.apache.http.impl.client.BasicCredentialsProvider;
 import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.http.impl.client.HttpClients;
-
-
-
 import org.apache.http.util.EntityUtils;
+import edu.harvard.iq.dataverse.util.json.JsonUtil;
+import jakarta.json.JsonObject;
 
 /**
  * DataCiteRESTfullClient
@@ -46,6 +46,7 @@ public class DataCiteRESTfullClient implements Closeable {
     private static final long RETRY_DELAY_MS = 10000; // 10 seconds
 
     private String url;
+    private String restApiUrl; 
     private CloseableHttpClient httpClient;
     private HttpClientContext context;
     private String encoding = "utf-8";
@@ -59,6 +60,17 @@ public DataCiteRESTfullClient(String url, String username, String password) {
 
         httpClient = HttpClients.createDefault();
     }
+    
+    public DataCiteRESTfullClient(String url, String restApiUrl, String username, String password) {
+        this.url = url;
+        this.restApiUrl = restApiUrl; 
+        context = HttpClientContext.create();
+        CredentialsProvider credsProvider = new BasicCredentialsProvider();
+        credsProvider.setCredentials(new AuthScope(null, -1), new UsernamePasswordCredentials(username, password));
+        context.setCredentialsProvider(credsProvider);
+
+        httpClient = HttpClients.createDefault();
+    }
 
     public void close() {
         if (this.httpClient != null) {
@@ -209,6 +221,57 @@ public String getMetadata(String doi) {
         }
     }
 
+    /**
+     * getMetadataViaRestApi
+     * a temporary/dev. version of the method utilizing REST API instead of MDS
+     *
+     * @param doi
+     * @return
+     */
+    public String getMetadataViaRestApi(String doi) {
+        HttpGet httpGet = new HttpGet(this.restApiUrl + "/dois/" + doi);
+
+        try {
+            HttpResponse response = executeWithRetry(httpGet, "getMetadataViaRestApi");
+            String restApiRawData = EntityUtils.toString(response.getEntity(), encoding);
+            
+            logger.fine("REST API raw data: " + restApiRawData);
+            
+            if (response.getStatusLine().getStatusCode() != 200) {
+                String errMsg = "getMetadataViaRestApi, Response: " + response.getStatusLine().getStatusCode() + ", " + restApiRawData;
+                logger.log(Level.SEVERE, errMsg);
+                throw new RuntimeException(errMsg);
+            }
+
+            JsonObject restApiJson = JsonUtil.getJsonObject(restApiRawData);
+            String xmlEncoded = null; 
+            
+            JsonObject restApiJsonData = restApiJson.getJsonObject("data");
+            if (restApiJsonData != null) {
+                JsonObject restApiJsonAttributes = restApiJsonData.getJsonObject("attributes");
+                if (restApiJsonAttributes != null) {
+                    xmlEncoded = restApiJsonAttributes.getString("xml");
+                }
+            }
+            logger.fine("encoded XML entry: " + xmlEncoded);
+            
+            String metadata = null; // what we want to return, registration metadata in the XML format
+
+            if (xmlEncoded != null) {
+                // Stripping any newlines below may be unnecessary - it is likely
+                // always returned as a continuous string; but shouldn't hurt 
+                // either. 
+                metadata = new String(Base64.getDecoder().decode(xmlEncoded.replaceAll("[\\r\\n]", "")), encoding);
+            }
+            
+            logger.fine("decoded XML metadata: " + metadata);
+            return metadata;
+        } catch (IOException ioe) {
+            logger.log(Level.SEVERE, "IOException in getMetadataViaRestApi", ioe);
+            throw new RuntimeException("IOException in getMetadataViaRestAPi", ioe);
+        }
+    }
+    
     /**
      * testDOIExists
      *