private async Task ApplyContentSecurityPolicy(TagHelperOutput output, string uniqueId)
{
ContentSecurityPolicyHelper cspHelper = new ContentSecurityPolicyHelper(ViewContext);
ContentSecurityPolicyInlineExecution currentInlineExecution = cspHelper.GetCurrentInlineExecution(output.TagName);
if (currentInlineExecution == ContentSecurityPolicyInlineExecution.Nonce)
{
output.Attributes.Add(ContentSecurityPolicyHelper.NonceAttribute, cspHelper.GetCurrentNonce());
}
else if (currentInlineExecution.IsHashBased())
{
string contentHash = null;
if (!String.IsNullOrEmpty(uniqueId))
{
contentHash = cspHelper.GetHashFromCache(uniqueId);
}
if (contentHash == null)
{
string content = output.Content.IsModified ? output.Content.GetContent() : (await output.GetChildContentAsync()).GetContent();
contentHash = ContentSecurityPolicyHelper.ComputeHash(currentInlineExecution, content);
if (!String.IsNullOrEmpty(uniqueId))
{
cspHelper.AddHashToCache(uniqueId, contentHash);
}
}
cspHelper.AddHashToInlineExecutionSources(output.TagName, contentHash);
}
}
public void Dispose()
{
if (_currentInlineExecution.IsHashBased())
{
StringBuilder elementInnerHtmlBuilder = ((StringWriter)_viewContext.Writer).GetStringBuilder();
string elementInnerHtml = elementInnerHtmlBuilder.ToString();
string elementHash = ContentSecurityPolicyHelper.ComputeHash(_currentInlineExecution, elementInnerHtml);
_cspHelper.AddHashToInlineExecutionSources(_elementTag.TagName, elementHash);
_viewContext.Writer.Dispose();
_viewContext.Writer = _viewContextWriter;
_viewContext.Writer.Write(elementInnerHtml);
}
_elementTag.TagRenderMode = TagRenderMode.EndTag;
_elementTag.WriteTo(_viewContext.Writer, HtmlEncoder.Default);
}