Replace HTTP request

I need to redirect http request as part of a filter addon.

I am using an nsIObserverService which provides me with subject, topic, and data.

I know how to cancel the request but I need to replace th开发者_StackOverflow中文版e request with a URL to a block page.

I know how to redirect the window contents with window.content.document.location.replace but that kills all subsequent requests.

I only want to replace at the request level.

Please advise.

Thanks in advance.

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on server that is processing your request try sending 301 response

for example an php redirect is like this

header('HTTP/1.1 301 Moved Permanently');
header('Location: http://www.example.com');
exit();