/// <summary>
/// Handle the related attribute types which exist upon the element exposed by the given context, if any.
/// </summary>
/// <returns>A response type providing information about the result of this operation.</returns>
/// <param name="context">The rendering context, which exposes a ZPT element.</param>
public AttributeHandlingResult Handle(IRenderingContext context)
{
if(context == null)
{
throw new ArgumentNullException(nameof(context));
}
IRenderingContext[] output = null;
var attribute = context.GetTalAttribute(ZptConstants.Tal.RepeatAttribute);
if(attribute != null)
{
string repeatVariableName, expression;
this.ParseAttributeValue(attribute, out repeatVariableName, out expression, context.Element);
var sequence = this.GetSequence(expression, context.TalModel, context);
if(sequence != null)
{
var repetitionInfos = this.GetRepetitions(sequence, context.Element, repeatVariableName);
output = this.HandleRepetitions(repetitionInfos, context);
}
}
if(output == null)
{
output = new [] { context };
}
return new AttributeHandlingResult(output, true);
}
/// <summary>
/// Handle the related attribute types which exist upon the element exposed by the given context, if any.
/// </summary>
/// <returns>A response type providing information about the result of this operation.</returns>
/// <param name="context">The rendering context, which exposes a ZPT element.</param>
public AttributeHandlingResult Handle(IRenderingContext context)
{
if(context == null)
{
throw new ArgumentNullException(nameof(context));
}
AttributeHandlingResult output;
var attrib = context.GetTalAttribute(ZptConstants.Tal.OmitTagAttribute);
if(attrib != null)
{
if(attrib.Value.Length == 0)
{
var children = context.Element.Omit();
output = new AttributeHandlingResult(new RenderingContext[0],
false,
children.Select(x => context.CreateSiblingContext(x)).ToArray());
}
else
{
// Normal handling by detecting an attribute and using its value
var result = context.TalModel.Evaluate(attrib.Value, context);
if(!result.CancelsAction && result.GetValueAsBoolean())
{
var children = context.Element.Omit();
output = new AttributeHandlingResult(new RenderingContext[0],
false,
children.Select(x => context.CreateSiblingContext(x)).ToArray());
}
else
{
output = new AttributeHandlingResult(new [] { context }, true);
}
}
}
else
{
output = new AttributeHandlingResult(new [] { context }, true);
}
return output;
}
/// <summary>
/// Handle the related attribute types which exist upon the element exposed by the given context, if any.
/// </summary>
/// <returns>A response type providing information about the result of this operation.</returns>
/// <param name="context">The rendering context, which exposes a ZPT element.</param>
public AttributeHandlingResult Handle(IRenderingContext context)
{
if(context == null)
{
throw new ArgumentNullException(nameof(context));
}
AttributeHandlingResult output;
var attrib = context.GetTalAttribute(ZptConstants.Tal.OnErrorAttribute);
if(attrib != null)
{
string mode;
var expressionResult = this.GetAttributeResult(attrib, context, out mode);
if(expressionResult.CancelsAction)
{
output = new AttributeHandlingResult(new [] { context }, true);
}
else if(expressionResult.Value == null)
{
context.Element.RemoveAllChildren();
output = new AttributeHandlingResult(new [] { context }, true);
}
else
{
context.Element.ReplaceChildrenWith(expressionResult.GetValue<string>(),
mode == STRUCTURE_INDICATOR);
output = new AttributeHandlingResult(new [] { context }, true);
}
ZptConstants.TraceSource.TraceInformation(Resources.LogMessageFormats.TalErrorHandled,
context.Element.GetFullFilePathAndLocation(),
nameof(OnErrorAttributeHandler),
nameof(Handle));
}
else
{
output = new AttributeHandlingResult(new [] { context }, true);
}
return output;
}
/// <summary>
/// Handle the related attribute types which exist upon the element exposed by the given context, if any.
/// </summary>
/// <returns>A response type providing information about the result of this operation.</returns>
/// <param name="context">The rendering context, which exposes a ZPT element.</param>
public AttributeHandlingResult Handle(IRenderingContext context)
{
if(context == null)
{
throw new ArgumentNullException(nameof(context));
}
AttributeHandlingResult output = new AttributeHandlingResult(new [] { context }, true);
var attribute = context.GetTalAttribute(ZptConstants.Tal.ConditionAttribute);
if(attribute != null)
{
ExpressionResult result;
try
{
result = context.TalModel.Evaluate(attribute.Value, context);
}
catch(Exception ex)
{
string message = String.Format(ExceptionMessages.ExpressionEvaluationException,
ZptConstants.Tal.Namespace,
ZptConstants.Tal.ConditionAttribute,
attribute.Value,
context.Element.Name);
throw new ModelEvaluationException(message, ex) {
ExpressionText = attribute.Value,
ElementName = context.Element.Name,
};
}
var removeElement = result.CancelsAction? false : !result.GetValueAsBoolean();
if(removeElement)
{
context.Element.Remove();
output = new AttributeHandlingResult(new RenderingContext[0], false);
}
}
return output;
}
/// <summary>
/// Visit the given context, as well as its child contexts, and return a collection of the resultant contexts.
/// </summary>
/// <remarks>
/// <para>
/// This operation performs the same work as <see cref="Visit"/>, but it then visits all of the resultant contexts,
/// recursively moving down the exposed document tree, visiting each context in turn.
/// </para>
/// <para>
/// In this implementation, the visit additionally provides error-handling via the TAL on-error attribute.
/// </para>
/// </remarks>
/// <returns>Zero or more <see cref="RenderingContext"/> instances, determined by the outcome of this visit.</returns>
/// <param name="context">The rendering context to visit.</param>
public override IRenderingContext[] VisitRecursively(IRenderingContext context)
{
IRenderingContext[] output;
try
{
output = base.VisitRecursively(context);
}
catch(RenderingException ex)
{
output = new [] { context };
if(context.GetTalAttribute(ZptConstants.Tal.OnErrorAttribute) != null)
{
context.TalModel.AddError(ex);
_errorHandler.Handle(context);
}
else
{
throw;
}
}
return output;
}
/// <summary>
/// Handle the related attribute types which exist upon the element exposed by the given context, if any.
/// </summary>
/// <returns>A response type providing information about the result of this operation.</returns>
/// <param name="context">The rendering context, which exposes a ZPT element.</param>
public AttributeHandlingResult Handle(IRenderingContext context)
{
if(context == null)
{
throw new ArgumentNullException(nameof(context));
}
var attrib = context.GetTalAttribute(ZptConstants.Tal.AttributesAttribute);
if(attrib != null)
{
var itemMatches = ItemMatcher
.Matches(attrib.Value)
.Cast<Match>()
.Select(x => Attribute.Match(x.Groups[1].Value));
if(itemMatches.Any(x => !x.Success))
{
string message = String.Format(Resources.ExceptionMessages.ZptAttributeParsingError,
ZptConstants.Tal.Namespace,
ZptConstants.Tal.AttributesAttribute,
attrib.Value);
throw new ParserException(message) {
SourceElementName = context.Element.Name,
SourceAttributeName = attrib.Name,
SourceAttributeValue = attrib.Value
};
}
var items = itemMatches
.Select(x => new { Prefix = x.Groups[1].Value,
AttributeName = x.Groups[2].Value,
Expression = x.Groups[3].Value })
.ToArray();
foreach(var item in items)
{
ExpressionResult result;
var unescapedExpression = this.UnescapeSemicolons(item.Expression);
try
{
result = context.TalModel.Evaluate(unescapedExpression, context);
}
catch(Exception ex)
{
string message = String.Format(Resources.ExceptionMessages.ExpressionEvaluationException,
ZptConstants.Tal.Namespace,
ZptConstants.Tal.AttributesAttribute,
item.Expression,
context.Element.Name);
throw new ModelEvaluationException(message, ex) {
ExpressionText = item.Expression,
ElementName = context.Element.Name,
};
}
if(!result.CancelsAction)
{
var nspace = new ZptNamespace(prefix: item.Prefix);
if(result.Value == null)
{
if(String.IsNullOrEmpty(item.Prefix))
{
context.Element.RemoveAttribute(item.AttributeName);
}
else
{
context.Element.RemoveAttribute(nspace, item.AttributeName);
}
}
else
{
if(String.IsNullOrEmpty(item.Prefix))
{
context.Element.SetAttribute(item.AttributeName, result.Value.ToString());
}
else
{
context.Element.SetAttribute(nspace, item.AttributeName, result.Value.ToString());
}
}
}
}
}
return new AttributeHandlingResult(new [] { context }, true);
}
/// <summary>
/// Gets either the TAL 'content' or 'replace' attribute from the given element.
/// </summary>
/// <returns>The attribute, or a <c>null</c> reference.</returns>
/// <param name="context">The rendering context.</param>
/// <param name="attribName">Exposes the name of the attribute.</param>
private IZptAttribute GetAttribute(IRenderingContext context, out string attribName)
{
IZptAttribute
contentAttrib = context.GetTalAttribute(ZptConstants.Tal.ContentAttribute),
replaceAttrib = context.GetTalAttribute(ZptConstants.Tal.ReplaceAttribute),
output;
if(contentAttrib != null
&& replaceAttrib != null)
{
string message = String.Format(ExceptionMessages.ContentAndReplaceAttributesCannotCoexist,
context.Element.Name);
throw new ParserException(message) {
SourceElementName = context.Element.Name
};
}
else if(contentAttrib != null)
{
output = contentAttrib;
attribName = ZptConstants.Tal.ContentAttribute;
}
else
{
output = replaceAttrib;
attribName = ZptConstants.Tal.ReplaceAttribute;
}
return output;
}