/// <summary>
/// Given an XML Node creates the relevant RDF/XML Events for it and recurses as necessary
/// </summary>
/// <param name="context">Parser Context</param>
/// <param name="node">The Node to create Event(s) from</param>
/// <param name="parent">The Parent Node of the given Node</param>
/// <returns></returns>
private ElementEvent GenerateEvents(RdfXmlParserContext context, XmlNode node, IRdfXmlEvent parent)
{
//Get the Base Uri
String baseUri = String.Empty;
if (parent is ElementEvent)
{
baseUri = ((ElementEvent)parent).BaseUri;
}
//Create an ElementEvent for the Node
ElementEvent element = new ElementEvent(node.LocalName, node.Prefix, baseUri, node.OuterXml);
//Set the initial Language from the Parent
ElementEvent parentEl = (ElementEvent)parent;
element.Language = parentEl.Language;
#region Attribute Processing
//Iterate over Attributes
bool parseTypeLiteral = false;
foreach (XmlAttribute attr in node.Attributes)
{
//Watch out for special attributes
if (attr.Name == "xml:lang")
{
//Set Language
element.Language = attr.Value;
}
else if (attr.Name == "xml:base")
{
//Set Base Uri
if (RdfXmlSpecsHelper.IsAbsoluteURI(attr.Value))
{
//Absolute Uri
element.BaseUri = attr.Value;
}
else if (!element.BaseUri.Equals(String.Empty))
{
//Relative Uri with a Base Uri to resolve against
//element.BaseUri += attr.Value;
element.BaseUri = Tools.ResolveUri(attr.Value, element.BaseUri);
}
else
{
//Relative Uri with no Base Uri
throw new RdfParseException("Cannot resolve a Relative Base URI since there is no in-scope Base URI");
}
}
else if (attr.Prefix == "xmlns")
{
//Register a Namespace
String uri;
if (attr.Value.StartsWith("http://"))
{
//Absolute Uri
uri = attr.Value;
}
else if (!element.BaseUri.Equals(String.Empty))
{
//Relative Uri with a Base Uri to resolve against
//uri = element.BaseUri + attr.Value;
uri = Tools.ResolveUri(attr.Value, element.BaseUri);
}
else
{
//Relative Uri with no Base Uri
throw new RdfParseException("Cannot resolve a Relative Namespace URI since there is no in-scope Base URI");
}
NamespaceAttributeEvent ns = new NamespaceAttributeEvent(attr.LocalName, uri, attr.OuterXml);
element.NamespaceAttributes.Add(ns);
}
else if (attr.Prefix == String.Empty && attr.Name == "xmlns")
{
//Register a Default Namespace (Empty Prefix)
String uri;
if (attr.Value.StartsWith("http://"))
{
//Absolute Uri
uri = attr.Value;
}
else if (!element.BaseUri.Equals(String.Empty))
{
//Relative Uri with a Base Uri to resolve against
//uri = element.BaseUri + attr.Value;
uri = Tools.ResolveUri(attr.Value, element.BaseUri);
}
else
{
//Relative Uri with no Base Uri
throw new RdfParseException("Cannot resolve a Relative Namespace URI since there is no in-scope Base URI");
}
NamespaceAttributeEvent ns = new NamespaceAttributeEvent(String.Empty, uri, attr.OuterXml);
element.NamespaceAttributes.Add(ns);
}
else if (attr.Prefix == "xml" || (attr.Prefix == String.Empty && attr.LocalName.StartsWith("xml")))
{
//Ignore other Reserved XML Names
}
else if (attr.Name == "rdf:parseType" && attr.Value == "Literal")
{
//Literal Parse Type
parseTypeLiteral = true;
//Create the Attribute
AttributeEvent attrEvent = new AttributeEvent(attr.LocalName, attr.Prefix, attr.Value, attr.OuterXml);
element.Attributes.Add(attrEvent);
//Set ParseType property correctly
element.ParseType = RdfXmlParseType.Literal;
}
else if (attr.Name == "rdf:parseType")
{
//Some other Parse Type
//Create the Attribute
AttributeEvent attrEvent = new AttributeEvent(attr.LocalName, attr.Prefix, attr.Value, attr.OuterXml);
element.Attributes.Add(attrEvent);
//Set the ParseType property correctly
if (attr.Value == "Resource")
{
element.ParseType = RdfXmlParseType.Resource;
}
else if (attr.Value == "Collection")
{
element.ParseType = RdfXmlParseType.Collection;
}
else
{
//Have to assume Literal
element.ParseType = RdfXmlParseType.Literal;
parseTypeLiteral = true;
//Replace the Parse Type attribute with one saying it is Literal
element.Attributes.Remove(attrEvent);
attrEvent = new AttributeEvent(attr.LocalName, attr.Prefix, "Literal", attr.OuterXml);
}
}
else
{
//Normal Attribute which we generate an Event from
AttributeEvent attrEvent = new AttributeEvent(attr.LocalName, attr.Prefix, attr.Value, attr.OuterXml);
element.Attributes.Add(attrEvent);
}
}
//Validate generated Attributes for Namespace Confusion and URIRef encoding
foreach (AttributeEvent a in element.Attributes)
{
//Namespace Confusion should only apply to Attributes without a Namespace specified
if (a.Namespace.Equals(String.Empty))
{
if (RdfXmlSpecsHelper.IsAmbigiousAttributeName(a.LocalName))
{
//Can't use any of the RDF terms that mandate the rdf: prefix without it
throw ParserHelper.Error("An Attribute with an ambigious name '" + a.LocalName + "' was encountered. The following attribute names MUST have the rdf: prefix - about, aboutEach, ID, bagID, type, resource, parseType", element);
}
}
//URIRef encoding check
if (!RdfXmlSpecsHelper.IsValidUriRefEncoding(a.Value))
{
throw ParserHelper.Error("An Attribute with an incorrectly encoded URIRef was encountered, URIRef's must be encoded in Unicode Normal Form C", a);
}
}
#endregion
//Don't proceed if Literal Parse Type is on
if (parseTypeLiteral)
{
//Generate an XMLLiteral from its Inner Xml (if any)
TypedLiteralEvent lit = new TypedLiteralEvent(node.InnerXml.Normalize(), RdfSpecsHelper.RdfXmlLiteral, node.InnerXml);
element.Children.Add(lit);
return element;
}
//Are there Child Nodes?
if (node.HasChildNodes)
{
//Take different actions depending on the Number and Type of Child Nodes
if (node.ChildNodes.Count > 1)
{
//Multiple Child Nodes
//Iterate over Child Nodes
foreach (XmlNode child in node.ChildNodes)
{
//Ignore Irrelevant Node Types
if (this.IsIgnorableNode(child))
{
continue;
}
//Generate an Event for the Child Node
ElementEvent childEvent = this.GenerateEvents(context, child, element);
element.Children.Add(childEvent);
}
}
else if (node.ChildNodes[0].NodeType == XmlNodeType.Text)
{
//Single Child which is a Text Node
//Generate a Text Event
TextEvent text = new TextEvent(node.InnerText.Normalize(), node.OuterXml);
element.Children.Add(text);
}
else if (node.ChildNodes[0].NodeType == XmlNodeType.CDATA)
{
//Single Child which is a CData Node
TextEvent text = new TextEvent(node.InnerXml.Normalize(), node.OuterXml);
element.Children.Add(text);
}
else
{
//Single Child which is not a Text Node
//Recurse on the single Child Node
if (!this.IsIgnorableNode(node.ChildNodes[0]))
{
ElementEvent childEvent = this.GenerateEvents(context, node.ChildNodes[0], element);
element.Children.Add(childEvent);
}
}
}
return element;
}
/// <summary>
/// Checks whether an attribute is an rdf:datatype attribute
/// </summary>
/// <param name="attr">Attribute to Test</param>
/// <returns>True if is an rdf:datatype attribute</returns>
public static bool IsDataTypeAttribute(AttributeEvent attr)
{
//QName must be rdf:datatype
if (attr.QName.Equals("rdf:datatype"))
{
//Must be a valid RDF Uri Reference
return IsRdfUriReference(attr.Value);
}
else
{
return false;
}
}
/// <summary>
/// Checks whether an attribute is an rdf:about attribute
/// </summary>
/// <param name="attr">Attribute to Test</param>
/// <returns>True if is an rdf:about attribute</returns>
public static bool IsAboutAttribute(AttributeEvent attr)
{
//QName must be rdf:id
if (attr.QName.Equals("rdf:about"))
{
//Must be a valid RDF Uri Reference
return IsRdfUriReference(attr.Value);
}
else
{
return false;
}
}
/// <summary>
/// Checks whether an attribute is an property attribute
/// </summary>
/// <param name="attr">Attribute to Test</param>
/// <returns>True if is an property attribute</returns>
public static bool IsPropertyAttribute(AttributeEvent attr)
{
//QName must be a valid Property Attribute Uri
//Any string value allowed so if Uri test is true then we're a property Attribute
return IsPropertyAttributeURI(attr.QName);
}
/// <summary>
/// Checks whether an attribute is an rdf:nodeID attribute
/// </summary>
/// <param name="attr">Attribute to Test</param>
/// <returns>True if is an rdf:nodeID attribute</returns>
/// <remarks>Does some validation on ID value but other validation occurs in the <see cref="ValidateID()">ValidateID</see> method which is called at other points in the Parsing</remarks>
public static bool IsNodeIDAttribute(AttributeEvent attr)
{
//QName must be rdf:nodeID
if (attr.QName.Equals("rdf:nodeID"))
{
//Must be a valid RDF ID
if (IsRdfID(attr.Value))
{
//OK
return true;
}
else
{
//Invalid RDF ID so Error
throw ParserHelper.Error("The value '" + attr.Value + "' for rdf:id is not valid, RDF IDs can only be valid NCNames as defined by the W3C XML Namespaces specification", attr);
}
}
else
{
return false;
}
}
