Here are the docs for Plug.Conn.get_session: Plug.Conn.html#get_session/1

And here is the key line from the docs:

Returns the whole session.

And here are the docs for Plug.Conn.fetch_session: Plug.Conn.html#fetch_session/2

And here is the key line:

Fetches the session from the session store. Will also fetch cookies.

Can anyone explain to me why there are two functions that appear to do almost the same thing? Why would I use one vs the other? What is the session store – why doesn’t get_session also get the session from the “session store”? Or does it?

Also, in a nutshell, what is the difference between a connection and a session? It seems to me like I should just be able to do something like conn.session – in fact, I don’t understand why there is something called a session if I already have a connection – why can’t any information stored in the session just be stored in the connection instead?

I don’t understand why there need to be these backflips between connections and sessions.