[feature] Add support for setting XQuery external variables of type attribute() via the eXist-db REST API

Author: adamretter

exist-core/src/main/java/org/exist/dom/memtree/DocumentImpl.java

@@ -1735,4 +1735,20 @@ public Node appendChild(final Node newChild) throws DOMException {
 
         throw unsupported();
     }
+
+    @Override
+    public String lookupNamespaceURI(final String prefix) {
+        if (prefix == null || prefix == XMLConstants.DEFAULT_NS_PREFIX) {
+            return XMLConstants.NULL_NS_URI;
+        }
+
+        for (int i = nextNamespace - 1; i >= 0; i--) {
+            final QName namespaceMapping = namespaceCode[i];
+            if (prefix.equals(namespaceMapping.getLocalPart())) {
+                return namespaceMapping.getNamespaceURI();
+            }
+        }
+
+        return null;
+    }
 }

exist-core/src/main/java/org/exist/dom/memtree/NodeImpl.java

@@ -921,7 +921,7 @@ public boolean isDefaultNamespace(final String namespaceURI) {
 
     @Override
     public String lookupNamespaceURI(final String prefix) {
-        throw unsupported();
+        return document.lookupNamespaceURI(prefix);
     }
 
     @Override

exist-core/src/main/java/org/exist/xqj/Marshaller.java

@@ -48,11 +48,11 @@
 import org.exist.dom.QName;
 import org.exist.dom.memtree.*;
 import org.exist.storage.DBBroker;
+import org.exist.storage.ElementValue;
 import org.exist.xquery.Expression;
 import org.exist.xquery.NameTest;
 import org.exist.xquery.XPathException;
 import org.exist.xquery.value.*;
-import org.w3c.dom.Attr;
 import org.w3c.dom.Comment;
 import org.w3c.dom.Document;
 import org.w3c.dom.Element;
@@ -63,6 +63,8 @@
 import org.xml.sax.SAXException;
 import org.xml.sax.helpers.AttributesImpl;
 
+import javax.annotation.Nullable;
+import javax.xml.XMLConstants;
 import javax.xml.stream.XMLInputFactory;
 import javax.xml.stream.XMLStreamConstants;
 import javax.xml.stream.XMLStreamException;
@@ -74,6 +76,8 @@
 import java.io.StringReader;
 import java.util.Properties;
 
+import static org.exist.util.StringUtil.nullIfEmpty;
+
 
 /**
  * A utility class that provides marshalling services for external variables and methods 
@@ -100,6 +104,8 @@ public class Marshaller {
     private final static String ATTR_TYPE = "type";
     private final static String ATTR_ITEM_TYPE = "item-type";
 
+    private final static String ATTR_NAME = "name";
+
     public final static QName ROOT_ELEMENT_QNAME = new QName(SEQ_ELEMENT, NAMESPACE, PREFIX);
 
     /**
@@ -267,8 +273,45 @@ public static Sequence demarshall(final NodeImpl node) throws XMLStreamException
                 type = Type.getType(typeName);
             }
 
+            // TODO(AR) coerce the item type to the type desired for the variable binding
+
+            @Nullable String attrNameString = null;
+            if (sxValue instanceof Element) {
+                attrNameString = nullIfEmpty(sxValue.getAttribute(ATTR_NAME));
+            }
             Node item = sxValue.getFirstChild();
-            if (Type.subTypeOf(type, Type.NODE)) {
+
+            if (type == Type.ATTRIBUTE || (type == Type.ITEM && attrNameString != null)) {
+                if (attrNameString.isEmpty()) {
+                    throw new XMLStreamException("sx:value must contain a name attribute if type is " + typeName);
+                }
+
+                final String attrPrefix;
+                final String attrNamespace;
+                final String attrLocalName;
+                final int colonSep = attrNameString.indexOf(':');
+                if (colonSep > -1) {
+                    attrPrefix = attrNameString.substring(0, colonSep);
+                    attrNamespace = item.lookupNamespaceURI(attrPrefix);
+                    if (attrNamespace == null) {
+                        throw new XMLStreamException("sx:value's name attribute contains the QName prefix '" +  attrPrefix + "' for which the namespace has not been declared if type is " + typeName);
+                    }
+                    attrLocalName = attrNameString.substring(colonSep + 1);
+                } else {
+                    attrPrefix = XMLConstants.DEFAULT_NS_PREFIX;
+                    attrNamespace = XMLConstants.NULL_NS_URI;
+                    attrLocalName = attrNameString;
+                }
+
+                final QName attrName = new QName(attrLocalName, attrNamespace, attrPrefix, ElementValue.ATTRIBUTE);
+                final MemTreeBuilder builder = new MemTreeBuilder();
+                builder.startDocument();
+                final int attrNodeNumber = builder.addAttribute(attrName, sxValue.getTextContent());
+                builder.endDocument();
+                final AttrImpl attr = (AttrImpl) builder.getDocument().getAttribute(attrNodeNumber);
+                result.add(attr);
+
+            } else if (Type.subTypeOf(type, Type.NODE)) {
 
                 switch (type) {
                     case Type.ELEMENT:
@@ -281,13 +324,6 @@ public static Sequence demarshall(final NodeImpl node) throws XMLStreamException
                         }
                         break;
 
-                    case Type.ATTRIBUTE:
-                        if (!(item instanceof Attr)) {
-                            throw new XMLStreamException("sx:value should only contain an Attribute if type is " + typeName);
-                        }
-                        result.add((AttrImpl) item);
-                        break;
-
                     case Type.COMMENT:
                         if (!(item instanceof Comment)) {
                             throw new XMLStreamException("sx:value should only contain a Comment node if type is " + typeName);

exist-core/src/main/xsd/rest-serialized-sequence.xsd

@@ -33,6 +33,7 @@
                 <xs:element name="value" minOccurs="0" maxOccurs="unbounded">
                     <xs:complexType mixed="true">
                         <xs:attribute name="type" type="xs:string" default="item()"/>
+                        <xs:attribute name="name" type="xs:string" use="optional"/>
                     </xs:complexType>
                 </xs:element>
             </xs:sequence>