Merge branch 'zj-mattermost-session' into 'master'

Mattermost session

This branch is based of tag v8.14.4 so I could test on an instance better.

But stuck on the tests, as setting up the whole doorkeeper stuff doesn't seem to be supported for testing.

See merge request !8033

1 files changed, 115 insertions, 0 deletions

diff --git a/lib/mattermost/session.rb b/lib/mattermost/session.rb
new file mode 100644
index 00000000000..fb8d7d97f8a
--- /dev/null
+++ b/lib/mattermost/session.rb
@@ -0,0 +1,115 @@
+module Mattermost
+  class NoSessionError < StandardError; end
+  # This class' prime objective is to obtain a session token on a Mattermost
+  # instance with SSO configured where this GitLab instance is the provider.
+  #
+  # The process depends on OAuth, but skips a step in the authentication cycle.
+  # For example, usually a user would click the 'login in GitLab' button on
+  # Mattermost, which would yield a 302 status code and redirects you to GitLab
+  # to approve the use of your account on Mattermost. Which would trigger a
+  # callback so Mattermost knows this request is approved and gets the required
+  # data to create the user account etc.
+  #
+  # This class however skips the button click, and also the approval phase to
+  # speed up the process and keep it without manual action and get a session
+  # going.
+  class Session
+    include Doorkeeper::Helpers::Controller
+    include HTTParty
+
+    base_uri Settings.mattermost.host
+
+    attr_accessor :current_resource_owner, :token
+
+    def initialize(current_user)
+      @current_resource_owner = current_user
+    end
+
+    def with_session
+      raise NoSessionError unless create
+
+      begin
+        yield self
+      ensure
+        destroy
+      end
+    end
+
+    # Next methods are needed for Doorkeeper
+    def pre_auth
+      @pre_auth ||= Doorkeeper::OAuth::PreAuthorization.new(
+        Doorkeeper.configuration, server.client_via_uid, params)
+    end
+
+    def authorization
+      @authorization ||= strategy.request
+    end
+
+    def strategy
+      @strategy ||= server.authorization_request(pre_auth.response_type)
+    end
+
+    def request
+      @request ||= OpenStruct.new(parameters: params)
+    end
+
+    def params
+      Rack::Utils.parse_query(oauth_uri.query).symbolize_keys
+    end
+
+    def get(path, options = {})
+      self.class.get(path, options.merge(headers: @headers))
+    end
+
+    def post(path, options = {})
+      self.class.post(path, options.merge(headers: @headers))
+    end
+
+    private
+
+    def create
+      return unless oauth_uri
+      return unless token_uri
+
+      @token = request_token
+      @headers = {
+        Authorization: "Bearer #{@token}"
+      }
+
+      @token
+    end
+
+    def destroy
+      post('/api/v3/users/logout')
+    end
+
+    def oauth_uri
+      return @oauth_uri if defined?(@oauth_uri)
+
+      @oauth_uri = nil
+
+      response = get("/api/v3/oauth/gitlab/login", follow_redirects: false)
+      return unless 300 <= response.code && response.code < 400
+
+      redirect_uri = response.headers['location']
+      return unless redirect_uri
+
+      @oauth_uri = URI.parse(redirect_uri)
+    end
+
+    def token_uri
+      @token_uri ||=
+        if oauth_uri
+          authorization.authorize.redirect_uri if pre_auth.authorizable?
+        end
+    end
+
+    def request_token
+      response = get(token_uri, follow_redirects: false)
+
+      if 200 <= response.code && response.code < 400
+        response.headers['token']
+      end
+    end
+  end
+end