/// <summary>
/// Searches through a <see cref="HalDocument"/> and removes any links that the current
/// principal does not have access to.
/// </summary>
/// <param name="that">
/// The <see cref="IOpenApiAccessChecker"/> that will be used to check the individual links.
/// </param>
/// <param name="target">
/// The <see cref="HalDocument"/> to check.
/// </param>
/// <param name="context">
/// The <see cref="IOpenApiContext"/> used to get information about the current principal.
/// </param>
/// <param name="options">
/// The <see cref="HalDocumentLinkRemovalOptions"/> to apply when checking links.
/// </param>
/// <returns>A task that completes when all links have been checked.</returns>
public static async Task RemoveForbiddenLinksAsync(this IOpenApiAccessChecker that, HalDocument target, IOpenApiContext context, HalDocumentLinkRemovalOptions options = default)
{
// First, we need to build a collection of all the links. For each one we need:
// 1. The link itself.
// 2. The HalDocument(s) to which it belongs - it is possible that we may encounter the same link twice and we need to be able to deal with that
// 3. The link relation name.
var linkMap = new Dictionary <(string, OpenApiWebLink), List <HalDocument> >();
AddHalDocumentLinksToMap(
target,
linkMap,
(options & HalDocumentLinkRemovalOptions.NonRecursive) == 0,
(options & HalDocumentLinkRemovalOptions.Unsafe) != 0);
// Build a second map of operation descriptors (needed to invoke the access policy check) to our OpenApiWebLinks.
var operationDescriptorMap = linkMap
.Keys
.Select(link => (Descriptor: new AccessCheckOperationDescriptor(link.Item2.Href, link.Item2.OperationId, link.Item2.OperationType.ToString().ToLowerInvariant()), Link: link))
.GroupBy(x => x.Descriptor)
.ToDictionary(descriptor => descriptor.Key, descriptor => descriptor.Select(link => link.Link).ToArray());
AccessCheckOperationDescriptor[] operationDescriptors = operationDescriptorMap.Keys.ToArray();
// Perform the access policy check.
IDictionary <AccessCheckOperationDescriptor, AccessControlPolicyResult> accessCheckResults = await that.CheckAccessPoliciesAsync(context, operationDescriptors).ConfigureAwait(false);
// Now use the results of the access policy check to remove links/documents that don't belong because the access policy denies them.
foreach (KeyValuePair <AccessCheckOperationDescriptor, AccessControlPolicyResult> accessCheckResult in accessCheckResults.Where(result => !result.Value.Allow))
{
foreach ((string, OpenApiWebLink)link in operationDescriptorMap[accessCheckResult.Key])
{
foreach (HalDocument document in linkMap[link])
{
document.RemoveLink(link.Item1, link.Item2);
// Also remove from embedded resources if present.
document.RemoveEmbeddedResource(link.Item1, link.Item2);
}
}
}
}
/// <summary>
/// An extension method that provides simpler syntax when using the <see cref="IOpenApiAccessChecker"/>
/// to check access for a single operation.
/// </summary>
/// <param name="checker">The underlying <see cref="IOpenApiAccessChecker"/> to use.</param>
/// <param name="context">The current <see cref="IOpenApiContext"/>.</param>
/// <param name="path">The request path.</param>
/// <param name="operationId">The request Operation Id.</param>
/// <param name="httpMethod">The request Http method.</param>
/// <returns>A task that resolves to the result of the access check.</returns>
public static async Task <AccessControlPolicyResult> CheckAccessPolicyAsync(
this IOpenApiAccessChecker checker,
IOpenApiContext context,
string path,
string operationId,
string httpMethod)
{
var request = new AccessCheckOperationDescriptor(path, operationId, httpMethod);
IDictionary <AccessCheckOperationDescriptor, AccessControlPolicyResult> result = await checker.CheckAccessPoliciesAsync(context, request).ConfigureAwait(false);
return(result.Values.Single());
}