* Check Google group membership with hasMember and get.
This PR is an enhancement built on
https://github.com/pusher/oauth2_proxy/pull/160. That PR reduces the
number of calls to the Google Admin API and simplifies the code by
using the hasMember method. It also supports checking membership in
nested groups.
However, the above message doesn't handle members who are not a part
of the domain. The hasMember API returns a 400 for that case. As a
fallback, when the API returns a 400, this change will try using the
`get` API which works as expected for members who aren't a part of the
domain. Supporting members who belong to the Google group but aren't
part of the domain is a requested feature from
https://github.com/pusher/oauth2_proxy/issues/95.
https://developers.google.com/admin-sdk/directory/v1/reference/members/get
Note that nested members who are not a part of the domain will not be
correctly detected with this change.
* Update CHANGELOG.
* Fix incorrect JSON and stop escaping strings.
* Add comments for each scenario.
When checking user membership against Google groups the groups are checked one
at a time and in the order that they were supplied. If one of the groups does
not exist then the checking is halted with the following error.
google.go:201: googleapi: Error 404: Resource Not Found: groupKey, notFound
None of the groups following the missing group are checked either. This means
that something as trivial as a typo in the first group will make it impossible
for anybody to login.
This change catches the 404, logs a message, and then carries on as usual. In
this way a typo will cause a particular group to stop working but will not
affect any other groups.
* New SessionState to consolidate email, access token and refresh token
* split ServeHttp into individual methods
* log on session renewal
* log on access token refresh
* refactor cookie encription/decription and session state serialization
