public async Task Invoke(HttpContext context)
{
// Invoke the 'normal' pipeline first.
// Note that the mvc middleware would serialize the response...
// Prevent that by injecting a custom IActionResultExecutor<ObjectResult>,
// that sets the ActionResult to the context instead of serializing.
await this.next(context);
// Our objectresultexecutor added some information on the HttpContext.
if (!context.Items.TryGetValue("HalFormattingContext", out object formatObject) ||
!(formatObject is HalFormattingContext halFormattingContext))
{
logger.LogDebug("Hal formatting context not found, other formatters are handling this response.");
return;
}
// some code to create a resource object from the result.
var rootResource = ConstructRootResource(halFormattingContext.ObjectResult);
halFormattingContext.ObjectResult.Value = rootResource;
// some code to figure out which actions/routes to embed.
var toEmbeds = GetRoutesToEmbed(halFormattingContext.ActionContext);
var requestFeature = context.Features.Get <IHttpRequestFeature>();
foreach (var toEmbed in toEmbeds)
{
var halRequestFeature = new HalHttpRequestFeature(requestFeature)
{
Method = "GET",
Path = toEmbed.Path
};
// The HalHttpContext creates a custom request and response in the constructor
// and creates a new feature collection with custom request and response features.
var halContext = new HalHttpContext(context, halRequestFeature);
await this.next(halContext);
// Now the custom ObjectResultExecutor set the ActionResult to a property of the custom HttpResponse.
var embedActionResult = ((HalHttpResponse)halContext.Response).ObjectResult;
// some code to embed the new actionresult.
Embed(rootResource, embedActionResult, toEmbed);
}
// Then invoke the default ObjectResultExecutor to serialize the new result.
await halFormattingContext.DefaultExecutor.ExecuteAsync(
halFormattingContext.ActionContext,
halFormattingContext.ObjectResult);
}
public async Task <HalResourceInspectedContext> OnResourceInspectionAsync(
HalResourceInspectingContext context,
HalResourceInspectionDelegate next)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (next == null)
{
throw new ArgumentNullException(nameof(next));
}
if (!context.IsRootResource)
{
throw new NotSupportedException("This inspector does not support embedded resources.");
}
if (context.Resource == null)
{
return(await next());
}
if (context.ActionContext == null)
{
throw new ArgumentException("ActionContext cannot be null.", nameof(context));
}
if (!(context.ActionContext.ActionDescriptor is ControllerActionDescriptor descriptor))
{
throw new HalException("Could not establish ControllerActionDescriptor reference.");
}
if (context.ActionContext.HttpContext == null || context.ActionContext.HttpContext.Features == null)
{
throw new ArgumentException("HttpContext features cannot be null.", nameof(context));
}
if (context.MvcPipeline == null)
{
throw new ArgumentException("Context does not contain the mvc pipeline.", nameof(context));
}
var requestFeature = context.ActionContext.HttpContext.Features.Get <IHttpRequestFeature>();
var links = linkService.GetLinks <HalEmbedAttribute>(descriptor, context.ActionContext, context.OriginalObject);
foreach (var link in links)
{
var halRequestFeature = new HalHttpRequestFeature(requestFeature)
{
Method = "GET",
Path = link.Uri
};
var halContext = new HalHttpContext(context.ActionContext.HttpContext, halRequestFeature);
logger.LogDebug("About to invoke MVC pipeline with a GET request on path '{0}'.", link.Uri);
await context.MvcPipeline.Pipeline(halContext);
var response = halContext.Response as HalHttpResponse;
if (response.StatusCode >= 200 && response.StatusCode <= 299)
{
logger.LogDebug("MVC pipeline returned success status code {0}. Invoking HAL resource factory.", response.StatusCode);
IResource embedded = await context.EmbeddedResourcePipeline(response.ActionContext, response.Resource);
embedded.Rel = link.Rel;
if (embedded is IResourceCollection collection)
{
if (collection.Collection != null)
{
logger.LogDebug("Embedding collection of {0} resources to rel '{0}'", collection.Collection.Count, link.Rel);
foreach (var item in collection.Collection)
{
item.Rel = link.Rel;
context.Resource.Embedded.Add(item);
}
}
}
else
{
logger.LogDebug("Embedding resource to rel '{0}'", link.Rel);
context.Resource.Embedded.Add(embedded);
}
}
else
{
logger.LogWarning("MVC pipeline returned non-success status code {0}. Ignoring result.", response.StatusCode);
}
}
var result = await next();
logger.LogTrace("After invoke next.");
return(result);
}
