// This isn't extensible right now.
//
// Returns true if the source is greedy (means to stop exploring the model)
// Returns false if the source in unknown or known but not greedy (like [FromQuery])
private static bool GetSource(ModelMetadata metadata, out ApiParameterSource source)
{
if (metadata.BinderMetadata == null)
{
// There's nothing we can figure out.
source = null;
return(false);
}
if (metadata.BinderMetadata is IFormatterBinderMetadata)
{
source = ApiParameterSource.Body;
return(true);
}
else if (metadata.BinderMetadata is IHeaderBinderMetadata)
{
source = ApiParameterSource.Header;
return(true);
}
else if (metadata.BinderMetadata is IServiceActivatorBinderMetadata)
{
source = ApiParameterSource.Hidden;
return(true);
}
else if (metadata.BinderMetadata is IRouteDataValueProviderMetadata)
{
source = ApiParameterSource.Path;
return(false);
}
else if (metadata.BinderMetadata is IQueryValueProviderMetadata)
{
source = ApiParameterSource.Query;
return(false);
}
else if (metadata.BinderMetadata is IFormDataValueProviderMetadata)
{
source = ApiParameterSource.Form;
return(false);
}
var binderTypeMetadata = metadata.BinderMetadata as IBinderTypeProviderMetadata;
if (binderTypeMetadata != null && binderTypeMetadata.BinderType != null)
{
// This provides it's own model binder, so we can't really make a good
// estimate of where it comes from.
source = ApiParameterSource.Custom;
return(true);
}
// We're out of cases we know how to handle.
source = null;
return(false);
}
private ApiParameterDescription CreateResult(
ModelMetadata metadata,
ApiParameterSource source,
string containerName)
{
return(new ApiParameterDescription()
{
ModelMetadata = metadata,
Name = GetName(containerName, metadata),
Source = source,
Type = metadata.ModelType,
});
}
public PropertyKey(ModelMetadata metadata, ApiParameterSource source)
{
ContainerType = metadata.ContainerType;
PropertyName = metadata.PropertyName;
Source = source;
}
/// <summary>
/// Visits a node in a model, and attempts to create <see cref="ApiParameterDescription"/> for any
/// model properties where we can definitely compute an answer.
/// </summary>
/// <param name="modelMetadata">The metadata for the model.</param>
/// <param name="ambientSource">The <see cref="ApiParameterSource"/> from the ambient context.</param>
/// <param name="containerName">The current name prefix (to prepend to property names).</param>
/// <returns>
/// <c>true</c> if the set of <see cref="ApiParameterDescription"/> objects were created for the model.
/// <c>false</c> if no <see cref="ApiParameterDescription"/> objects were created for the model.
/// </returns>
/// <remarks>
/// Its the reponsibility of this method to create a parameter description for ALL of the current model
/// or NONE of it. If a parameter description is created for ANY sub-properties of the model, then a parameter
/// description will be created for ALL of them.
/// </remarks>
private bool Visit(ModelMetadata modelMetadata, ApiParameterSource ambientSource, string containerName)
{
ApiParameterSource source;
if (GetSource(modelMetadata, out source))
{
// We have a definite answer for this model. This is a greedy source like
// [FromBody] so there's no need to consider properties.
Context.Results.Add(CreateResult(modelMetadata, source, containerName));
return(true);
}
// For any property which is a leaf node, we don't want to keep traversing:
//
// 1) Collections - while it's possible to have binder attributes on the inside of a collection,
// it hardly seems useful, and would result in some very wierd binding.
//
// 2) Simple Types - These are generally part of the .net framework - primitives, or types which have a
// type converter from string.
//
// 3) Types with no properties. Obviously nothing to explore there.
//
if (modelMetadata.IsCollectionType ||
!modelMetadata.IsComplexType ||
!modelMetadata.Properties.Any())
{
if (source == null || source == ambientSource)
{
// If it's a leaf node, and we have no new source then we don't know how to bind this.
// Return without creating any parameters, so that this can be included in the parent model.
return(false);
}
else
{
// We found a new source, and this model has no properties. This is probabaly
// a simple type with an attribute like [FromQuery].
Context.Results.Add(CreateResult(modelMetadata, source, containerName));
return(true);
}
}
// This will come from composite model binding - so investigate what's going on with each property.
//
// Basically once we find something that we know how to bind, we want to treat all properties at that
// level (and higher levels) as separate parameters.
//
// Ex:
//
// public IActionResult PlaceOrder(OrderDTO order) {...}
//
// public class OrderDTO
// {
// public int AccountId { get; set; }
//
// [FromBody]
// public Order { get; set; }
// }
//
// This should result in two parameters:
//
// AccountId - source: Any
// Order - source: Body
//
var propertyCount = 0;
var unboundProperties = new HashSet <ModelMetadata>();
// We don't want to append the **parameter** name when building a model name.
var newContainerName = containerName;
if (modelMetadata.ContainerType != null)
{
newContainerName = GetName(containerName, modelMetadata);
}
foreach (var propertyMetadata in modelMetadata.Properties)
{
propertyCount++;
var key = new PropertyKey(propertyMetadata, source);
if (Visited.Add(key))
{
if (!Visit(propertyMetadata, source ?? ambientSource, newContainerName))
{
unboundProperties.Add(propertyMetadata);
}
}
else
{
unboundProperties.Add(propertyMetadata);
}
}
if (unboundProperties.Count == propertyCount)
{
if (source == null || source == ambientSource)
{
// No properties were bound and we didn't find a new source, let the caller handle it.
return(false);
}
else
{
// We found a new source, and didn't create a result for any of the properties yet,
// so create a result for the current object.
Context.Results.Add(CreateResult(modelMetadata, source, containerName));
return(true);
}
}
else
{
// This model was only partially bound, so create a result for all the other properties
foreach (var property in unboundProperties)
{
// Create a 'default' description for each property
Context.Results.Add(CreateResult(property, source ?? ambientSource, newContainerName));
}
return(true);
}
}
