如何使用URL的过滤器列表监控和阻止流量？

I'm trying to create an app that monitors all incoming traffic and blocks it if required and if necessary, replace it with traffic from elsewhere. (preferably using a filter list made up of URL's) is there any possible way to do this? I have searched Google, and stack overflow and I have not been able to find anything relevant to my needs. thank you very much for any help in advance.I'm trying to create an app that monitors all i