public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
{
await base.ProcessAsync(context, output);
var mptxInstance = _mptxInstanceProvider.GetInstance();
if (mptxInstance == null)
{
throw new InvalidOperationException("No active MPTX instance.");
}
var currentHref = output.Attributes["href"].Value.ToString();
var newHref = QueryHelpers.AddQueryString(
currentHref,
Constants.InstanceIdQueryParameter,
mptxInstance.InstanceId);
output.Attributes.SetAttribute("href", newHref);
}
public override void Process(TagHelperContext context, TagHelperOutput output)
{
if (!output.Attributes.ContainsName(AttributeName))
{
return;
}
var mptxInstance = _mptxInstanceContextProvider.GetInstance();
if (mptxInstance == null)
{
throw new InvalidOperationException("No active MPTX instance.");
}
var mptxInstanceId = mptxInstance.InstanceId;
if (output.Attributes.ContainsName("href"))
{
HandleHref();
}
else if (output.Attributes.ContainsName("action"))
{
HandleAction();
}
else
{
throw new NotSupportedException($"Cannot determine how to append provider context.");
}
output.Attributes.RemoveAll(AttributeName);
void HandleAction()
{
var method = output.Attributes["method"]?.Value.ToString() ?? "post";
if (method.Equals("GET", StringComparison.OrdinalIgnoreCase))
{
var input = new TagBuilder("input");
input.Attributes.Add("type", "hidden");
input.Attributes.Add("name", Constants.InstanceIdQueryParameter);
input.Attributes.Add("value", mptxInstanceId);
output.PreContent.AppendHtml(input);
}
else
{
var currentAction = output.Attributes["action"].Value.ToString();
var newHref = QueryHelpers.AddQueryString(
currentAction,
Constants.InstanceIdQueryParameter,
mptxInstanceId);
output.Attributes.SetAttribute("action", newHref);
}
}
void HandleHref()
{
var currentHref = output.Attributes["href"].Value.ToString();
var newHref = QueryHelpers.AddQueryString(
currentHref,
Constants.InstanceIdQueryParameter,
mptxInstanceId);
output.Attributes.SetAttribute("href", newHref);
}
}