public bool Accept(ActionConstraintContext context)
{
var queryString = context.RouteContext.HttpContext.Request.QueryString.ToUriComponent();
var queryStringComponent = queryString.StartsWith("?", StringComparison.Ordinal) ? queryString.Substring(1) : queryString;
var queryData = new QueryStringParameterCollection(queryStringComponent);
var exactCandidates = context.Candidates.Where(c => c.Action.Parameters.Count == queryData.Count);
var selectedCandidate = SelectExactCandidate(exactCandidates, queryData);
if (context.CurrentCandidate.Action == selectedCandidate?.Action)
{
return(true);
}
var overloadedCandidates = context.Candidates.Where(c => c.Action.Parameters.Count > queryData.Count)
.OrderByDescending(c => c.Action.Parameters.Count);
selectedCandidate = SelectOverloadedCandidate(overloadedCandidates, queryData);
if (context.CurrentCandidate.Action == selectedCandidate?.Action)
{
return(true);
}
return(false);
}
private ActionSelectorCandidate SelectOverloadedCandidate(IEnumerable <ActionSelectorCandidate> candidates, QueryStringParameterCollection queryData)
{
foreach (var candidate in candidates)
{
var action = candidate.Action;
var isMatch = true;
var exactCount = 0;
foreach (var actionParam in action.Parameters)
{
var nameProvider = actionParam.BindingInfo as IModelNameProvider;
var name = nameProvider?.Name ?? actionParam.Name;
if (queryData.ContainsKey(name))
{
if (HasFromQueryAttribute(actionParam))
{
if (queryData[name].Count() > 1 && !IsCollection(actionParam.ParameterType))
{
isMatch = false;
break;
}
exactCount++;
}
else
{
// parameter with the right name but without FromQueryAttribute
isMatch = false;
break;
}
}
else
{
if (HasFromQueryAttribute(actionParam))
{
// parameter was expected in the query string
isMatch = false;
break;
}
}
}
if (isMatch && exactCount == queryData.Count)
{
return(candidate);
}
}
return(null);
}
private ActionSelectorCandidate SelectExactCandidate(IEnumerable <ActionSelectorCandidate> candidates, QueryStringParameterCollection queryData)
{
foreach (var candidate in candidates)
{
var action = candidate.Action;
var isMatch = true;
foreach (var actionParam in action.Parameters)
{
var nameProvider = actionParam.BindingInfo as IModelNameProvider;
var name = nameProvider?.Name ?? actionParam.Name;
if (queryData.ContainsKey(name))
{
isMatch = HasFromQueryAttribute(actionParam);
if (!isMatch)
{
break;
}
if (queryData[name].Count() > 1 && !IsCollection(actionParam.ParameterType))
{
isMatch = false;
break;
}
}
else
{
isMatch = false;
break;
}
}
if (isMatch)
{
return(candidate);
}
}
return(null);
}
