TL;DR: wget has a mode capable of saving cookies.

The other day I thought it'd be interesting to have a local copy of a confluence wiki, to avoid hitting the internet every time I needed a howto. So, I've tried curl first and failed (probably my fault really). So, after a few tries, I managed to get a workflow in place.

First, we need to log in onto the site:

./wget -qO- --keep-session-cookies \
  --save-cookies cookies.txt \
  --post-data 'os_username=<user>&os_password=<user>' \
  https://site.com/confluence/login.action

Here, you need to replace the user name and password with something meaningful. Please note that text must be escaped with something like this encoder.

The command will create a file cookies.txt which will contain the session cookie. Now, all you need to do is to mirror the site:

./wget --load-cookies cookies.txt \
  -mkxKEp \
  -np \
  https://site.com/confluence/display/PROJECT/

..and presto! you have the site mirrored locally!

HTH,