metadata record section of an OAI result needs a namespace - otherwise...

metadata record section of an OAI result needs a namespace - otherwise standard OAI clients are not able to fetch the result

app/modules/ElasticsearchComponent.scala

@@ -61,8 +61,13 @@ trait ElasticsearchComponent extends OaiRepository {
     searchResponse match  {
       case Success(searchResponse) =>
         val si = searchResponse.getScrollId
-        println(si)
-        val resumptionToken: Option[ResumptionToken] = Option(searchResponse.getScrollId).map(
+
+        //scroll_id is always the same -> for this specific context
+        //condition to finish the fetching is to compare the length of the resultlist
+        //compare: https://www.elastic.co/guide/en/elasticsearch/client/java-api/current/java-search-scrolling.html
+        //otherwise we will get into an empty loop
+        val scrollId = if (searchResponse.getHits.getHits.length == 0) Option.empty[String] else Option(searchResponse.getScrollId)
+        val resumptionToken: Option[ResumptionToken] = scrollId.map(
           ESResumptionTokenHelper(_))
 
         val myMap = searchResponse.getHits.getHits.map(hit => (hit.getId, hit.getSourceAsMap)).map(

app/org/swissbib/memobase/oai/response/OaiResponse.scala

@@ -33,7 +33,9 @@ sealed abstract class OaiResponse {
     val oaiFrame =
 
       /*<OAI-PMH xmlns="http://www.openarchives.org/OAI/2.0/" >*/
-        <OAI-PMH xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/OAI-PMH.xsd" xmlns="http://www.openarchives.org/OAI/2.0/"  >
+    //  <OAI-PMH xmlns="http://www.openarchives.org/OAI/2.0/"  >
+        <OAI-PMH xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/ http://www.openarchives.org/OAI/2.0/OAI-PMH.xsd" xmlns="http://www.openarchives.org/OAI/2.0/"  >
+
         <responseDate>{Instant.now()}</responseDate>
         {createRequestTag}
       </OAI-PMH>

app/resources/recordnscreation.xsl

+<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="2.0"
+                xmlns:fn="http://www.w3.org/2005/xpath-functions"
+                exclude-result-prefixes="fn">
+    <!--xmlns:fn="http://www.w3.org/2005/xpath-functions"> -->
+
+    <xsl:output method="xml"
+                encoding="UTF-8"
+                indent="yes"
+                omit-xml-declaration="yes"
+    />
+
+    <!--
+    <xsl:attribute-set name="edm">
+        <xsl:attribute name="edm">https://europeana.org/irgendwas</xsl:attribute>
+    </xsl:attribute-set>
+    -->
+    <xsl:template match="record">
+
+        <xsl:element  namespace="https://europeana.org/irgendwas"  name="edm:{local-name()}">
+
+
+            <xsl:apply-templates select="@*|node()"/>
+        </xsl:element>
+
+
+    </xsl:template>
+
+
+    <xsl:template match="@*|node()">
+        <xsl:copy-of select="."/>
+    </xsl:template>
+
+</xsl:stylesheet>
+

app/utilities/Json2XML.scala

@@ -14,7 +14,6 @@ object Json2XML {
 
   def singleJsonDoc2Xml(doc: JsValue, root: String = "record"): Elem = {
 
-    //only Helper function until we know how and produce valid OAI data
     val esJsonRespone = JsObject(Seq(root -> doc)).toString
     val config = new JsonXMLConfigBuilder().multiplePI(false).build();
     val output = new StringWriter()
@@ -28,7 +27,11 @@ object Json2XML {
     prettyWriter.add(reader)
     reader.close()
     writer.close()
-    scala.xml.XML.loadString(output.toString)
+
+
+    //at least the record tag of the metadata section for each document needs a namespace.
+    //otherwise standard OAI client tools are not able to process the result
+    scala.xml.XML.loadString(new TemplateTransformer(output.toString).transform(XSLTWrapper.edmNamespaceTransformer))
 
   }
 

app/utilities/TemplateCreator.java

+package utilities;
+
+import javax.xml.transform.Transformer;
+import javax.xml.transform.TransformerConfigurationException;
+import javax.xml.transform.TransformerFactory;
+import javax.xml.transform.stream.StreamSource;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+
+
+public class TemplateCreator {
+
+    private String templatePath;
+
+    public TemplateCreator(String transformerFactory,
+                           String templatePath) {
+        this(templatePath);
+        System.setProperty("javax.xml.transform.TransformerFactory",transformerFactory);
+    }
+
+    public TemplateCreator(String templatePath) {
+        this.templatePath = templatePath;
+        //as a more general solution we do not use net.sf.saxon.TransformerFactoryImpl as default
+        //System.setProperty("javax.xml.transform.TransformerFactory","net.sf.saxon.TransformerFactoryImpl");
+
+    }
+
+
+    public Transformer createTransformer() {
+        TransformerFactory transformerFactory = TransformerFactory.newInstance();
+        StreamSource source = null;
+
+        Transformer transformer = null;
+
+        if (new File(templatePath).exists()) {
+            source = new StreamSource(templatePath);
+            try {
+                transformer = transformerFactory.newTransformer(source);
+            } catch (TransformerConfigurationException ex) {
+                ex.printStackTrace();
+
+            }
+        }
+        return transformer;
+    }
+
+
+    public Transformer createTransformerFromResource() {
+        TransformerFactory transformerFactory = TransformerFactory.newInstance();
+        StreamSource source = null;
+
+        Transformer transformer = null;
+        //ClassLoader classLoader = TemplateCreator.class.getClassLoader();
+        ClassLoader classLoader = TemplateCreator.class.getClassLoader();
+        //try (InputStream is =  getClass()
+        //        .getClassLoader().getResourceAsStream(templatePath)) {
+        try (InputStream is =  classLoader.getResourceAsStream(templatePath)) {
+            source = new StreamSource(is);
+            transformer = transformerFactory.newTransformer(source);
+        } catch (TransformerConfigurationException | IOException exc) {
+            throw new RuntimeException(exc);
+        }
+
+        return transformer;
+    }
+
+
+
+}

app/utilities/TemplateTransformer.java

+package utilities;
+
+
+import javax.xml.transform.Source;
+import javax.xml.transform.Transformer;
+import javax.xml.transform.TransformerException;
+import javax.xml.transform.stream.StreamResult;
+import javax.xml.transform.stream.StreamSource;
+import java.io.StringReader;
+import java.io.StringWriter;
+import java.util.HashMap;
+
+public class TemplateTransformer {
+
+    private final StringReader record;
+
+    public TemplateTransformer(String recordToTransform) {
+        record = new StringReader(recordToTransform);
+    }
+
+    public XSLTDataObject transformIntoDataObject(Transformer transformer) {
+
+        StringWriter transformedRecord = getTransformation(transformer);
+
+        XSLTDataObject dataObject = new XSLTDataObject();
+        dataObject.record = transformedRecord.toString();
+        dataObject.additions = new HashMap<>();
+
+        return dataObject;
+
+    }
+
+    public String transform(Transformer transformer) {
+
+        StringWriter transformedRecord = getTransformation(transformer);
+        return transformedRecord.toString();
+
+    }
+
+    StringWriter getTransformation(Transformer transformer) {
+        Source source = new StreamSource(record);
+        StringWriter transformedRecord = new StringWriter();
+        StreamResult target = new StreamResult(transformedRecord);
+
+        try {
+
+            transformer.transform(source, target);
+        } catch (TransformerException tex) {
+            throw new RuntimeException(tex);
+        }
+
+        return transformedRecord;
+
+    }
+
+
+
+}

app/utilities/XSLTDataObject.java

+package utilities;
+
+import java.util.HashMap;
+
+/**
+ * Created by swissbib on 29.05.17.
+ */
+public class XSLTDataObject {
+
+    public HashMap<String,String> additions = new HashMap<>();
+
+    public String record = "";
+
+
+    @Override
+    public String toString() {
+        return record;
+    }
+}

app/utilities/XSLTWrapper.scala

+package utilities
+
+import javax.xml.transform.Transformer
+
+object XSLTWrapper {
+
+  val TRANSFORMERIMPL = "net.sf.saxon.TransformerFactoryImpl"
+  val EDM_namespace = "resources/recordnscreation.xsl"
+
+  lazy val edmNamespaceTransformer: Transformer = {
+    new TemplateCreator(TRANSFORMERIMPL, EDM_namespace).createTransformerFromResource
+  }
+
+}

build.sbt

@@ -36,7 +36,8 @@ lazy val root = (project in file("."))
       scala_xml_module,
       upickl,
       httprequests,
-      jwtcore
+      jwtcore,
+      saxonhe
     ),
     scalacOptions ++= Seq(
       "-feature",

project/Dependencies.scala

@@ -42,5 +42,7 @@ object Dependencies {
 
   lazy val jwtcore = "com.pauldijou" %% "jwt-core" % "4.3.0"
 
+  lazy val saxonhe = "net.sf.saxon" % "Saxon-HE" % "10.2"
+
 
 }