public async Task ApplyAsync(HttpContext httpContext, EndpointSelectorContext context, CandidateSet candidates)
{
if (httpContext == null)
{
throw new ArgumentNullException(nameof(httpContext));
}
if (candidates == null)
{
throw new ArgumentNullException(nameof(candidates));
}
// There's no real benefit here from trying to avoid the async state machine.
// We only execute on nodes that contain a dynamic policy, and thus always have
// to await something.
for (var i = 0; i < candidates.Count; i++)
{
if (!candidates.IsValidCandidate(i))
{
continue;
}
var endpoint = candidates[i].Endpoint;
var metadata = endpoint.Metadata.GetMetadata <DynamicPageMetadata>();
if (metadata == null)
{
continue;
}
var matchedValues = candidates[i].Values;
var endpoints = _selector.SelectEndpoints(metadata.Values);
if (endpoints.Count == 0)
{
// If there's no match this is a configuration error. We can't really check
// during startup that the action you configured exists.
throw new InvalidOperationException(
"Cannot find the fallback endpoint specified by route values: " +
"{ " + string.Join(", ", metadata.Values.Select(kvp => $"{kvp.Key}: {kvp.Value}")) + " }.");
}
// It is possible to have more than one result for pages but they are equivalent.
var compiled = await _loader.LoadAsync(endpoints[0].Metadata.GetMetadata <PageActionDescriptor>());
var replacement = compiled.Endpoint;
// We need to provide the route values associated with this endpoint, so that features
// like URL generation work.
var values = new RouteValueDictionary(metadata.Values);
// Include values that were matched by the fallback route.
foreach (var kvp in matchedValues)
{
values.TryAdd(kvp.Key, kvp.Value);
}
candidates.ReplaceEndpoint(i, replacement, values);
}
}
public async Task ApplyAsync(HttpContext httpContext, CandidateSet candidates)
{
if (httpContext == null)
{
throw new ArgumentNullException(nameof(httpContext));
}
if (candidates == null)
{
throw new ArgumentNullException(nameof(candidates));
}
// There's no real benefit here from trying to avoid the async state machine.
// We only execute on nodes that contain a dynamic policy, and thus always have
// to await something.
for (var i = 0; i < candidates.Count; i++)
{
if (!candidates.IsValidCandidate(i))
{
continue;
}
var endpoint = candidates[i].Endpoint;
var originalValues = candidates[i].Values;
RouteValueDictionary dynamicValues = null;
// We don't expect both of these to be provided, and they are internal so there's
// no realistic way this could happen.
var dynamicPageMetadata = endpoint.Metadata.GetMetadata <DynamicPageMetadata>();
var transformerMetadata = endpoint.Metadata.GetMetadata <DynamicPageRouteValueTransformerMetadata>();
if (dynamicPageMetadata != null)
{
dynamicValues = dynamicPageMetadata.Values;
}
else if (transformerMetadata != null)
{
var transformer = (DynamicRouteValueTransformer)httpContext.RequestServices.GetRequiredService(transformerMetadata.SelectorType);
dynamicValues = await transformer.TransformAsync(httpContext, originalValues);
}
else
{
// Not a dynamic page
continue;
}
if (dynamicValues == null)
{
candidates.ReplaceEndpoint(i, null, null);
continue;
}
var endpoints = _selector.SelectEndpoints(dynamicValues);
if (endpoints.Count == 0 && dynamicPageMetadata != null)
{
// Having no match for a fallback is a configuration error. We can't really check
// during startup that the action you configured exists, so this is the best we can do.
throw new InvalidOperationException(
"Cannot find the fallback endpoint specified by route values: " +
"{ " + string.Join(", ", dynamicValues.Select(kvp => $"{kvp.Key}: {kvp.Value}")) + " }.");
}
else if (endpoints.Count == 0)
{
candidates.ReplaceEndpoint(i, null, null);
continue;
}
// We need to provide the route values associated with this endpoint, so that features
// like URL generation work.
var values = new RouteValueDictionary(dynamicValues);
// Include values that were matched by the fallback route.
if (originalValues != null)
{
foreach (var kvp in originalValues)
{
values.TryAdd(kvp.Key, kvp.Value);
}
}
// Update the route values
candidates.ReplaceEndpoint(i, endpoint, values);
var loadedEndpoints = new List <Endpoint>(endpoints);
for (var j = 0; j < loadedEndpoints.Count; j++)
{
var compiled = await _loader.LoadAsync(loadedEndpoints[j].Metadata.GetMetadata <PageActionDescriptor>());
loadedEndpoints[j] = compiled.Endpoint;
}
// Expand the list of endpoints
candidates.ExpandEndpoint(i, loadedEndpoints, _comparer);
}
}