This incredible piece of software allows you to execute shell commands on your local machine, from your browser, via websockets.
Why would anyone do such a thing, you ask? I'm using it to demonstrate shell-based stuff in my browser-based presentations using Shower. As soon as I've made the JavaScript side of this process presentable, I will open-source it and link it here.
The server allows to execute arbitrary commands, only limited by the permissions of the user it is being run with (read: don't run as root please). The server binds to localhost, and will not accept any remote connections by default.
Clone, run go get (because we depend on go.net/websocket) and then go run main.go -path initial/working/directory. You can now send websocket messages to http://localhost:8080/exec, according to the protocol defined below.
They're executed using exec.Command, wrapped into a bash -c 'your command' invocation. This allows you to do bash stuff like touch bar && cat foo > bar.
An exception is the cd command. Since commands executed using exec.Command run using the parent processes working directory, running bash -c 'cd ..' would be quite useless, as it doesn't change the working directory of the parent. Thus if the command begins with cd (cd followed by a space), the command is not run using bash -c and instead changes the working directory of the websocket-tty process.
After spending several minutes researching state of the art command execution protocols, I came up with the following JSON messages.
Request:
{ "Cmd": "ls -la" }
Response:
{ "Result": "foo\nbar\nbaz", "Error": "" }
If "Error" is empty in the response, no error occurred.
If that's something you want, I'd be thrilled :) Drop me a pull request.