/// <inheritdoc />
public ActionDescriptor SelectBestCandidate(RouteContext context, IReadOnlyList <ActionDescriptor> candidates)
{
RouteData routeData = context.RouteData;
ODataPath odataPath = context.HttpContext.ODataFeature().Path;
IDictionary <string, object> routingConventionsStore = context.HttpContext.ODataFeature().RoutingConventionsStore;
if (odataPath != null && routeData.Values.ContainsKey(ODataRouteConstants.Action))
{
// Get the available parameter names from the route data. Ignore case of key names.
// Remove route prefix and other non-parameter values from availableKeys
IList <string> availableKeys = routeData.Values.Keys
.Where((key) => !RoutingConventionHelpers.IsRouteParameter(key) &&
key != ODataRouteConstants.Action &&
key != ODataRouteConstants.ODataPath &&
key != ODataRouteConstants.MethodInfo)
.Select(k => k.ToLowerInvariant())
.ToList();
int availableKeysCount = 0;
if (routingConventionsStore.ContainsKey(ODataRouteConstants.KeyCount))
{
availableKeysCount = (int)routingConventionsStore[ODataRouteConstants.KeyCount];
}
// Filter out types we know how to bind out of the parameter lists. These values
// do not show up in RouteData() but will bind properly later.
IEnumerable <ActionIdAndParameters> considerCandidates = candidates
.Select(c => new ActionIdAndParameters(
id: c.Id,
parameterCount: c.Parameters.Count,
filteredParameters: c.Parameters.Where(p => p.ParameterType != typeof(ODataPath) &&
!ODataQueryParameterBindingAttribute.ODataQueryParameterBinding.IsODataQueryOptions(p.ParameterType) &&
!IsParameterFromQuery(c as ControllerActionDescriptor, p.Name)),
descriptor: c));
// retrieve the optional parameters
routeData.Values.TryGetValue(ODataRouteConstants.OptionalParameters, out object wrapper);
ODataOptionalParameter optionalWrapper = wrapper as ODataOptionalParameter;
// Find the action with the all matched parameters from available keys including
// matches with no parameters and matches with parameters bound to the body.
// Ordered first by the total number of matched
// parameters followed by the total number of parameters. Ignore case of
// parameter names. The first one is the best match.
//
// Assume key,relatedKey exist in RouteData. 1st one wins:
// Method(ODataPath,ODataQueryOptions) vs Method(ODataPath).
// Method(key,ODataQueryOptions) vs Method(key).
// Method(key,ODataQueryOptions) vs Method(key).
// Method(key,relatedKey) vs Method(key).
// Method(key,relatedKey,ODataPath) vs Method(key,relatedKey).
List <ActionIdAndParameters> matchedCandidates = considerCandidates
.Where(c => TryMatch(context, c.ActionDescriptor, c.FilteredParameters, availableKeys,
optionalWrapper, c.TotalParameterCount, availableKeysCount))
.OrderByDescending(c => c.FilteredParameters.Count)
.ThenByDescending(c => c.TotalParameterCount)
.ToList();
// if there are still multiple candidate actions at this point, let's try some tie-breakers
if (matchedCandidates.Count > 1)
{
// prioritize actions with explicit [ODataRoute] (i.e. attribute routing)
ActionIdAndParameters bestCandidate = matchedCandidates.FirstOrDefault(candidate =>
candidate.ActionDescriptor is ControllerActionDescriptor action &&
action.MethodInfo.GetCustomAttributes <ODataRouteAttribute>().Any());
if (bestCandidate != null)
{
return(bestCandidate.ActionDescriptor);
}
// Next in priority, actions which explicitly declare the request method
// e.g. using [AcceptVerbs("POST")], [HttpPost], etc.
bestCandidate = matchedCandidates.FirstOrDefault(candidate =>
ActionAcceptsMethod(candidate.ActionDescriptor as ControllerActionDescriptor, context.HttpContext.Request.Method));
if (bestCandidate != null)
{
return(bestCandidate.ActionDescriptor);
}
// also priorize actions that have the exact number of parameters as available keys
// this helps disambiguate between overloads of actions that implement actions
// e.g. DoSomething(int key) vs DoSomething(), if there are no availableKeys, the
// selector could still think that the `int key` param will come from the request body
// and end up returning DoSomething(int key) instead of DoSomething()
bestCandidate = matchedCandidates.FirstOrDefault(candidate => candidate.FilteredParameters.Count() == availableKeysCount);
if (bestCandidate != null)
{
return(bestCandidate.ActionDescriptor);
}
}
return(matchedCandidates.Select(c => c.ActionDescriptor).FirstOrDefault());
}
return(_innerSelector.SelectBestCandidate(context, candidates));
}
bool TryMatch(
HttpContext context,
ActionIdAndParameters action,
ISet <string> availableKeys,
IDictionary <string, object> conventionsStore,
IReadOnlyList <IEdmOptionalParameter> optionalParameters,
int availableKeysCount)
{
var parameters = action.FilteredParameters;
var totalParameterCount = action.TotalParameterCount;
if (availableKeys.Contains(ODataRouteConstants.NavigationProperty))
{
availableKeysCount -= 1;
}
if (totalParameterCount < availableKeysCount)
{
return(false);
}
var matchedBody = false;
var keys = conventionsStore.Keys.ToArray();
for (var i = 0; i < parameters.Count; i++)
{
var parameter = parameters[i];
var parameterName = parameter.Name;
if (availableKeys.Contains(parameterName))
{
continue;
}
var matchesKey = false;
for (var j = 0; j < keys.Length; j++)
{
if (keys[j].Contains(parameterName, StringComparison.Ordinal))
{
matchesKey = true;
break;
}
}
if (matchesKey)
{
continue;
}
if (context.Request.Query.ContainsKey(parameterName))
{
continue;
}
if (parameter is ControllerParameterDescriptor param && optionalParameters.Count > 0)
{
if (param.ParameterInfo.IsOptional && optionalParameters.Any(p => string.Equals(p.Name, parameterName, StringComparison.OrdinalIgnoreCase)))
{
continue;
}
}
if (ParameterHasRegisteredModelBinder(parameter))
{
continue;
}
if (!matchedBody && RequestHasBody(context))
{
matchedBody = true;
continue;
}
return(false);
}
return(true);
}