public async Task InvokeAsync(HttpContext context)
{
// If Umbraco hasn't been installed yet, the middleware shouldn't do anything (interacting with the
// redirects service will fail as the database isn't setup yet)
if (_runtimeState.Level == RuntimeLevel.Install)
{
await _next(context);
return;
}
string pathAndQuery = context.Request.GetEncodedPathAndQuery();
// Ignore all /umbraco/ requests
if (pathAndQuery.IndexOf("/umbraco/", StringComparison.InvariantCultureIgnoreCase) == 0)
{
await _next(context);
return;
}
context.Response.OnStarting(() => {
switch (context.Response.StatusCode)
{
case StatusCodes.Status404NotFound: {
// Get the URI of the inbound request
Uri uri = context.Request.GetUri();
// Invoke the pre lookup event
RedirectPreLookupNotification preLookup = new(context);
_eventAggregator.Publish <IRedirectPreLookupNotification>(preLookup);
// Get the destination URL from the arguments (in case a value has been set
// from an notification handler)
string destinationUrl = preLookup.DestinationUrl;
// Declare a variable for the redirect (either from the pre lookup or a lookup via the service)
IRedirect redirect = preLookup.Redirect ?? _redirectsService.GetRedirectByRequest(context.Request);
// Return if we neither have a redirect or a destination URL
if (redirect == null && string.IsNullOrWhiteSpace(destinationUrl))
{
return(Task.CompletedTask);
}
// Determine the redirect type
RedirectType redirectType = preLookup.RedirectType ?? redirect?.Type ?? RedirectType.Temporary;
// Calculate the destination URL
destinationUrl ??= _redirectsService.GetDestinationUrl(redirect, uri);
// Invoke the post lookup event
RedirectPostLookupNotification postLookup = new(context, redirect, redirectType, destinationUrl);
_eventAggregator.Publish <IRedirectPostLookupNotification>(postLookup);
// Extract the values from the notification
redirectType = postLookup.RedirectType;
destinationUrl = postLookup.DestinationUrl;
// The destination URL should have a value at this point. If the value is empty, it's most
// likely because it was emptied via the post look up notification
if (string.IsNullOrWhiteSpace(destinationUrl))
{
return(Task.CompletedTask);
}
// Respond with a redirect based on the redirect type
switch (redirectType)
{
// If redirect is of type permanent, trigger a 301 redirect
case RedirectType.Permanent:
context.Response.Redirect(destinationUrl, true);
break;
// If redirect is of type temporary, trigger a 307 redirect
case RedirectType.Temporary:
context.Response.Redirect(destinationUrl, false, true);
break;
}
break;
}
}
return(Task.CompletedTask);
});
await _next(context);
}
/// <summary>
/// Returns the calculated destination URL for the specified <paramref name="redirect"/>.
/// </summary>
/// <param name="redirect">The redirect.</param>
/// <param name="uri">The inbound URL.</param>
/// <param name="redirectsService">A reference to the current redirects service.</param>
/// <returns>The destination URL.</returns>
public static string GetDestinationUrl(this OutboundRedirect redirect, Uri uri, IRedirectsService redirectsService)
{
return(redirectsService.GetDestinationUrl(redirect, uri));
}
