Hooking pipeline to web search

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I'm not that satisfied with the search query generation via template. I think pipelines can make it better. Yet, I have absolutely no idea how to even get started on the script. I have tried reading examples in the repo but it brings more questions than answers. What the Valves and Pipeline class do? What functions I need to implement? What's the differences between pipelines and filters? Can someone give some hint on how to use it, even in such an early stages. Thanks in advance.