protected override SelectQueryPart Parse(string parameterValue)
{
var matches = Regex.Matches(parameterValue, @"(?:\w+/)*\w+", RegexOptions.IgnoreCase).Cast <Match>();
var selectors = new List <MemberAccessFilterExpression>();
foreach (var match in matches)
{
var s = match.Value.Split('/');
var selector = s
.Aggregate <string, MemberAccessFilterExpression>(null, FilterExpression.MemberAccess);
selectors.Add(selector);
}
return(ODataQueryPart.Select(selectors.ToArray()));
}
public override void VisitSelectClause(SelectClause selectClause, QueryModel queryModel)
{
var selectors = new List <string>();
if (selectClause.Selector.NodeType == ExpressionType.MemberAccess)
{
// TODO: handle access of child properties in selector statements
var selector = (MemberExpression)selectClause.Selector;
selectors.Add(selector.Member.Name);
}
else if (selectClause.Selector.NodeType == ExpressionType.New)
{
// TODO: trying to support this may not be viable...
var constructor = (NewExpression)selectClause.Selector;
foreach (var argument in constructor.Arguments)
{
if (argument.NodeType == ExpressionType.MemberAccess)
{
var member = (MemberExpression)argument;
selectors.Add(member.Member.Name);
}
else
{
throw new NotSupportedException("Cannot select non-members from the result set.");
}
}
}
else if (selectClause.Selector.NodeType == ExpressionType.MemberInit)
{
var memberInit = (MemberInitExpression)selectClause.Selector;
var constructor = memberInit.NewExpression;
foreach (var argument in constructor.Arguments)
{
if (argument.NodeType == ExpressionType.MemberAccess)
{
var member = (MemberExpression)argument;
selectors.Add(member.Member.Name);
}
else
{
throw new NotSupportedException("Cannot select non-members from the result set.");
}
}
foreach (var memberBinding in memberInit.Bindings)
{
if (memberBinding.BindingType == MemberBindingType.Assignment)
{
var assignment = (MemberAssignment)memberBinding;
if (assignment.Expression.NodeType == ExpressionType.MemberAccess)
{
var selectedMember = (MemberExpression)assignment.Expression;
if (memberBinding.Member.Name == selectedMember.Member.Name)
{
selectors.Add(selectedMember.Member.Name);
}
else
{
throw new NotSupportedException($"Cannot alias member '{selectedMember.Member.Name}' as '{memberBinding.Member.Name}'. Aliasing projections is not supported in LinqToRest.");
}
}
else
{
throw new NotSupportedException("Cannot select non-members into the result set.");
}
}
else
{
throw new NotSupportedException("Cannot select lists from the result set.");
}
}
}
if (selectors.Any())
{
_query.SelectPredicate = ODataQueryPart.Select(selectors.Distinct().Select(FilterExpression.MemberAccess).ToArray());
}
base.VisitSelectClause(selectClause, queryModel);
}
