/// <summary>
/// Returns the string result from evaluating an xpath expression against the given document and
/// context created from key/value pairs.
/// </summary>
/// <example>
/// string result = BuildComponentUtilities.EvalXPathExpr(doc, "concat($key, '.htm')", "key", "file");
/// </example>
public static string EvalXPathExpr(IXPathNavigable doc, XPathExpression xpe, params string[] keyValuePairs) {
Debug.Assert(keyValuePairs.Length % 2 == 0);
CustomContext cc = new CustomContext();
for (int i = 0; i < keyValuePairs.Length; i += 2)
cc[keyValuePairs[i]] = keyValuePairs[i + 1];
return EvalXPathExpr(doc, xpe, cc);
}
/// <summary>
/// Returns the string result from evaluating an xpath expression against the given document and context.
/// </summary>
public static string EvalXPathExpr(IXPathNavigable doc, XPathExpression xpe, CustomContext c) {
XPathExpression t = xpe.Clone();
t.SetContext(c);
return doc.CreateNavigator().Evaluate(t).ToString();
}
public TargetInfo GetTargetInfo (XPathNavigator linkNode, CustomContext context) {
// compute the metadata file name to open
XPathExpression localFileExpression = fileExpression.Clone();
localFileExpression.SetContext(context);
string file = linkNode.Evaluate(localFileExpression).ToString();
if (String.IsNullOrEmpty(file)) return (null);
// load the metadata file
XPathDocument metadataDocument = GetDocument(file);
if (metadataDocument == null) return (null);
// querry the metadata file for the target url and link text
XPathNavigator metadataNode = metadataDocument.CreateNavigator();
XPathExpression localUrlExpression = urlExpression.Clone();
localUrlExpression.SetContext(context);
string url = metadataNode.Evaluate(localUrlExpression).ToString();
XPathExpression localTextExpression = textExpression.Clone();
localTextExpression.SetContext(context);
string text = metadataNode.Evaluate(localTextExpression).ToString();
// return this information
TargetInfo info = new TargetInfo(url, text, type);
return (info);
}
public TargetInfo GetTargetInfo (XPathNavigator linkNode, CustomContext context) {
foreach (TargetDirectory targetDirectory in targetDirectories) {
TargetInfo info = targetDirectory.GetTargetInfo(linkNode, context);
if (info != null) return (info);
}
return (null);
}
private static CustomContext GetContext (XPathNavigator configuration) {
CustomContext context = new CustomContext();
XPathNodeIterator context_nodes = configuration.Select("context");
foreach (XPathNavigator context_node in context_nodes) {
string prefix = context_node.GetAttribute("prefix", String.Empty);
string name = context_node.GetAttribute("name", String.Empty);
context.AddNamespace(prefix, name);
}
return(context);
}
