/// <summary>
/// Gets all events from the XML DOM
/// </summary>
/// <param name="context">Parser Context</param>
public void GetAllEvents(RdfXmlParserContext context)
{
RootEvent root;
XmlNodeList nodes = _document.GetElementsByTagName("rdf:RDF");
if (nodes.Count == 0)
{
// Not using rdf:RDF
root = GenerateEventTree(context, _document.DocumentElement);
}
else if (nodes.Count > 1)
{
throw new RdfParseException("XML contains multiple rdf:RDF Nodes and is therefore not a valid RDF/XML Document");
}
else
{
// Must thus be only 1 rdf:RDF element
root = GenerateEventTree(context, nodes[0]);
}
FlattenEventTree(context, root, 0);
}
/// <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 (IsIgnorableNode(child))
{
continue;
}
// Generate an Event for the Child Node
ElementEvent childEvent = 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 (!IsIgnorableNode(node.ChildNodes[0]))
{
ElementEvent childEvent = GenerateEvents(context, node.ChildNodes[0], element);
element.Children.Add(childEvent);
}
}
}
return(element);
}
/// <summary>
/// Takes the Event Tree and Flattens it into a Queue as per the rules laid out in the RDF/XML Specification
/// </summary>
/// <param name="context">Parser Context</param>
/// <param name="evt">Event which is the Root of the Tree (not necessarily a RootEvent)</param>
/// <param name="nesting">A numeric value used for Parser Tracing to indicate nesting levels of the Event Tree</param>
private void FlattenEventTree(RdfXmlParserContext context, IRdfXmlEvent evt, int nesting)
{
// Add to Queue
context.Events.Enqueue(evt);
if (context.TraceParsing)
{
Console.Write(nesting + " " + evt.GetType().ToString());
}
// Iterate over Children where present
if (evt is RootEvent)
{
RootEvent root = (RootEvent)evt;
if (context.TraceParsing)
{
Console.WriteLine("");
}
foreach (IRdfXmlEvent childEvent in root.Children)
{
FlattenEventTree(context, childEvent, nesting + 1);
}
// No End after a RootEvent
return;
}
else if (evt is ElementEvent)
{
ElementEvent element = (ElementEvent)evt;
if (context.TraceParsing)
{
Console.WriteLine(" " + element.Namespace + ":" + element.LocalName);
}
if (element.Children.Count > 0)
{
foreach (IRdfXmlEvent childEvent in element.Children)
{
FlattenEventTree(context, childEvent, nesting + 1);
}
}
}
else if (evt is TextEvent)
{
TextEvent text = (TextEvent)evt;
if (context.TraceParsing)
{
Console.WriteLine(" " + text.Value);
}
// No additional End after a Text Event
return;
}
else if (evt is TypedLiteralEvent)
{
TypedLiteralEvent tlit = (TypedLiteralEvent)evt;
if (context.TraceParsing)
{
Console.WriteLine();
}
// No additional End after a Text Event
return;
}
// Add an End Element Event to the Queue
EndElementEvent end = new EndElementEvent();
context.Events.Enqueue(end);
if (context.TraceParsing)
{
String endDescrip = String.Empty;
if (evt is ElementEvent)
{
ElementEvent temp = (ElementEvent)evt;
endDescrip = " " + temp.QName;
}
Console.WriteLine(nesting + " " + end.GetType().ToString() + endDescrip);
}
}
/// <summary>
/// Given an XML Node that is the Root of the RDF/XML section of the Document Tree creates the RootEvent and generates the rest of the Event Tree by recursive calls to the <see cref="GenerateEvents">GenerateEvents</see> method
/// </summary>
/// <param name="context">Parser Context</param>
/// <param name="docEl">XML Node that is the Root of the RDF/XML section of the Document Tree</param>
/// <returns></returns>
private RootEvent GenerateEventTree(RdfXmlParserContext context, XmlNode docEl)
{
// Get the Document Element
// XmlNode docEl = document.DocumentElement;
// Generate a Root Event and Element Event from it
RootEvent root = new RootEvent(docEl.BaseURI, docEl.OuterXml);
if (docEl.BaseURI.Equals(String.Empty))
{
if (context.BaseUri != null)
{
root.BaseUri = context.BaseUri.AbsoluteUri;
}
}
ElementEvent element = new ElementEvent(docEl.LocalName, docEl.Prefix, root.BaseUri, docEl.OuterXml);
// Initialise Language Settings
root.Language = String.Empty;
element.Language = root.Language;
// Set as Document Element and add as only Child
root.DocumentElement = element;
root.Children.Add(element);
#region Attribute Processing
// Go through attributes looking for XML Namespace Declarations
foreach (XmlAttribute attr in docEl.Attributes)
{
if (attr.Prefix.Equals("xmlns") || attr.Name == "xmlns")
{
// Define a Namespace
String prefix = attr.LocalName;
if (prefix.Equals("xmlns"))
{
prefix = String.Empty;
}
String uri;
if (attr.Value.StartsWith("http://"))
{
// Absolute Uri
uri = attr.Value;
}
else if (!root.BaseUri.Equals(String.Empty))
{
// Relative Uri with a Base Uri to resolve against
// uri = root.BaseUri + attr.Value;
uri = Tools.ResolveUri(attr.Value, root.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");
}
context.Namespaces.AddNamespace(prefix, UriFactory.Create(uri));
}
else if (attr.Name == "xml:base")
{
// Set the Base Uri
String baseUri = attr.Value;
if (RdfXmlSpecsHelper.IsAbsoluteURI(baseUri))
{
// Absolute Uri
root.BaseUri = baseUri;
}
else if (!element.BaseUri.Equals(String.Empty))
{
// Relative Uri with a Base Uri to resolve against
// root.BaseUri += baseUri;
root.BaseUri = Tools.ResolveUri(baseUri, root.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");
}
element.BaseUri = root.BaseUri;
}
}
#endregion
// Iterate over Children
foreach (XmlNode child in docEl.ChildNodes)
{
// Ignore Irrelevant Node Types
if (IsIgnorableNode(child))
{
continue;
}
// Generate an Event for the Child Node
ElementEvent childEvent = GenerateEvents(context, child, element);
element.Children.Add(childEvent);
}
// Return the Root Event
return(root);
}
