Command interface

[cortesi]

I'm opening this ticket to capture a conversation on Slack, before it disappears. I feel that Mitmweb should support an arbitrary command interface, similar to the command execution mode in mitmproxy console. Commands are very powerful, and enable interactions with the proxy that simply weren't possible before without scripting. They're also the primary way for addons to expose operations to users, and addon authors should be confident that the user will be able to invoke those commands whichever tool they're using. In short, they're a major new core component of our project, and I'd like there to be consistency between all our UI tools.

The primary command interface in mitmweb doesn't need to look like the one in console. There, a vim-like text interface is idiomatic. In mitmweb, there's an opportunity to do something more interesting. All arguments and returns are typed, and the type system is going to become more expressive next time I have time to turn to it. This means that you can pick up a command, and build a rich interface for it with file pickers for paths, selectors for options, and with special support for flow and cut selectors. The result might be a command palette, where the user can select a command, and then execute it with a nice set of native controls. That said, we should also retain the ability for a user to just cut-and-paste a full command so they can be shared.