RazorViewPage GetViewInstance(ViewResult viewResult, ViewRenderingContext context)
{
var view = Activator.CreateInstance(viewResult.ViewType) as RazorViewPage;
this.HydrateView(viewResult, view, context);
return(view);
}
public async Task Render(ViewResult viewResult, PipelineContext context, ViewRenderingContext viewRenderingContext)
{
var razorPage = this.GetViewInstance(viewResult, context);
var viewBufferScope = this.container.Resolve <IViewBufferScope>();
var bodyWriter = await this.RenderPageAsync(viewBufferScope, razorPage, viewRenderingContext);
await this.RenderLayoutAsync(viewBufferScope, razorPage, viewResult, viewRenderingContext, bodyWriter);
}
public override StringBuilder Render(ViewResult viewResult, ViewRenderingContext context)
{
var view = this.GetViewInstance(viewResult, context);
view.ExecuteView(null, null);
var body = view.Body;
var sectionContents = view.SectionContents;
// null means no override, string.Empty means ensure there is no layout
if (viewResult.MasterPageOverride != null)
{
view.Layout = viewResult.MasterPageOverride;
}
var root = string.IsNullOrWhiteSpace(view.Layout);
// render the initial view, and move "up" through its parent layouts
while (!root)
{
Type masterType;
try
{
masterType = this.viewResolver.Resolve(view.Layout);
}
catch (Exception ex)
{
throw new Exception($"Unable to resolve layout for view: {view}", ex);
}
var masterResult = new ViewResult(masterType, viewResult.AreaName, viewResult.ViewData, viewResult.StatusCode);
view = this.GetViewInstance(masterResult, context);
view.ExecuteView(body, sectionContents);
body = view.Body;
sectionContents = view.SectionContents;
root = !view.HasLayout;
}
return(new StringBuilder(body));
}
public override void Execute(PipelineContext context, ViewResult result)
{
StringBuilder rendered;
var renderer = this.viewRendererFinder.FindViewRenderer(result.ViewType);
var renderingContext = new ViewRenderingContext
{
RequestUrl = context.Request.Url,
RequestState = context.Request.State,
ContextItems = context.Items
};
try
{
rendered = renderer.Render(result, renderingContext);
}
catch (Exception e)
{
log.Error(e, "Error rendering view `{ViewName}`", result.ViewType.FullName);
#if DEBUG
if (Debugger.IsAttached)
{
Debugger.Break();
}
#endif
// TODO: render something useful
context.Response.ContentType = "text/plain";
context.Response.StatusCode = HttpStatusCode.InternalServerError;
return;
}
context.Response.SetCacheHeaders(result);
context.Response.StatusCode = result.StatusCode;
context.Response.Write(rendered.ToString());
context.Response.ContentType = "text/html";
SetLinkHeaders(context, result);
SetTempData(context, result.TempData);
}
public override async Task Execute(PipelineContext context, ViewResult result)
{
var rendered = new StringBuilder();
var renderer = this.viewRendererFinder.FindViewRenderer(result.ViewType);
var renderingContext = new ViewRenderingContext
{
Writer = new StringWriter(rendered)
};
try
{
await renderer.Render(result, context, renderingContext);
}
catch (Exception e)
{
log.Error(e, "Error rendering view `{ViewName}`", result.ViewType.FullName);
#if DEBUG
if (Debugger.IsAttached)
{
Debugger.Break();
}
#endif
// TODO: render something useful
context.Response.StatusCode = HttpStatusCode.InternalServerError;
return;
}
context.Response.SetCacheHeaders(result);
context.Response.StatusCode = result.StatusCode;
context.Response.ContentType = "text/html";
SetLinkHeaders(context, result);
this.tempDataMechanism.SetTempData(context, result.TempData);
await context.Response.Write(rendered.ToString());
}
async Task RenderLayoutAsync(IViewBufferScope bufferScope, IRazorPage previousPage, ViewResult viewResult, ViewRenderingContext viewRenderingContext, ViewBufferTextWriter bodyWriter)
{
// A layout page can specify another layout page. We'll need to continue
// looking for layout pages until they're no longer specified.
var renderedLayouts = new List <IRazorPage>();
// This loop will execute Layout pages from the inside to the outside. With each
// iteration, bodyWriter is replaced with the aggregate of all the "body" content
// (including the layout page we just rendered).
while (!string.IsNullOrEmpty(previousPage.Layout))
{
if (!bodyWriter.IsBuffering)
{
// Once a call to RazorPage.FlushAsync is made, we can no longer render Layout pages - content has
// already been written to the client and the layout content would be appended rather than surround
// the body content. Throwing this exception wouldn't return a 500 (since content has already been
// written), but a diagnostic component should be able to capture it.
var message = "Resources.FormatLayoutCannotBeRendered(Path, nameof(New.RazorPage.FlushAsync))";
throw new InvalidOperationException(message);
}
var layoutPage = this.GetLayoutPage(viewResult, previousPage.PipelineContext, previousPage.Layout);
if (renderedLayouts.Count > 0 && renderedLayouts.Any(l => l.GetType() == layoutPage.GetType()))
{
// If the layout has been previously rendered as part of this view, we're potentially in a layout
// rendering cycle.
throw new InvalidOperationException("Layout has circular reference. Previous Page: `" + previousPage.GetType() + "`, Current Layout: `" + layoutPage.GetType() + "`");
}
// Notify the previous page that any writes that are performed on it are part of sections being written
// in the layout.
previousPage.IsLayoutBeingRendered = true;
layoutPage.PreviousSectionWriters = previousPage.SectionWriters;
layoutPage.BodyContent = bodyWriter.Buffer;
bodyWriter = await this.RenderPageAsync(bufferScope, layoutPage, viewRenderingContext);
renderedLayouts.Add(layoutPage);
previousPage = layoutPage;
}
// Now we've reached and rendered the outer-most layout page. Nothing left to execute.
// Ensure all defined sections were rendered or RenderBody was invoked for page without defined sections.
foreach (var layoutPage in renderedLayouts)
{
layoutPage.EnsureRenderedBodyOrSections();
}
if (bodyWriter.IsBuffering)
{
// If IsBuffering - then we've got a bunch of content in the view buffer. How to best deal with it
// really depends on whether or not we're writing directly to the output or if we're writing to
// another buffer.
var viewBufferTextWriter = viewRenderingContext.Writer as ViewBufferTextWriter;
if (viewBufferTextWriter == null || !viewBufferTextWriter.IsBuffering)
{
// This means we're writing to a 'real' writer, probably to the actual output stream.
// We're using PagedBufferedTextWriter here to 'smooth' synchronous writes of IHtmlContent values.
using (var writer = bufferScope.CreateWriter(viewRenderingContext.Writer))
await bodyWriter.Buffer.WriteToAsync(writer, this.htmlEncoder);
}
else
{
// This means we're writing to another buffer. Use MoveTo to combine them.
bodyWriter.Buffer.MoveTo(viewBufferTextWriter.Buffer);
}
}
}
async Task <ViewBufferTextWriter> RenderPageAsync(IViewBufferScope bufferScope, IRazorPage page, ViewRenderingContext viewRenderingContext)
{
var writer = viewRenderingContext.Writer as ViewBufferTextWriter;
if (writer == null)
{
// If we get here, this is likely the top-level page (not a partial) - this means
// that context.Writer is wrapping the output stream. We need to buffer, so create a buffered writer.
var buffer = new ViewBuffer(bufferScope, page.GetType().AssemblyQualifiedName, ViewBuffer.ViewPageSize);
writer = new ViewBufferTextWriter(buffer, viewRenderingContext.Writer.Encoding, this.htmlEncoder, viewRenderingContext.Writer);
}
else
{
// This means we're writing something like a partial, where the output needs to be buffered.
// Create a new buffer, but without the ability to flush.
var buffer = new ViewBuffer(bufferScope, page.GetType().AssemblyQualifiedName, ViewBuffer.ViewPageSize);
writer = new ViewBufferTextWriter(buffer, viewRenderingContext.Writer.Encoding);
}
// The writer for the body is passed through the ViewContext, allowing things like HtmlHelpers
// and ViewComponents to reference it.
var oldWriter = viewRenderingContext.Writer;
//var oldFilePath = context.ExecutingFilePath;
viewRenderingContext.Writer = writer;
//context.ExecutingFilePath = page.Path;
try
{
page.RenderingContext = viewRenderingContext;
await page.ExecuteAsync();
return(writer);
}
finally
{
viewRenderingContext.Writer = oldWriter;
//context.ExecutingFilePath = oldFilePath;
}
}
