4 files changed, 64 insertions, 1 deletions
diff --git a/lib/mattermost/client.rb b/lib/mattermost/client.rb
new file mode 100644
index 00000000000..2a0e4b400d3
--- /dev/null
+++ b/lib/mattermost/client.rb
@@ -0,0 +1,39 @@
+module Mattermost
+  class Client
+    attr_reader :user
+
+    def initialize(user)
+      @user = user
+    end
+
+    private
+
+    def with_session(&blk)
+      Session.new(user).with_session(&blk)
+    end
+
+    def json_get(path, options = {})
+      with_session do |session|
+        json_response session.get(path, options)
+      end
+    end
+
+    def json_post(path, options = {})
+      with_session do |session|
+        json_response session.post(path, options)
+      end
+    end
+
+    def json_response(response)
+      json_response = JSON.parse(response.body)
+
+      if response.success?
+        json_response
+      elsif json_response['message']
+        raise json_response['message']
+      else
+        raise 'Undefined error'
+      end
+    end
+  end
+end
diff --git a/lib/mattermost/command.rb b/lib/mattermost/command.rb
new file mode 100644
index 00000000000..d1e4bb0eccf
--- /dev/null
+++ b/lib/mattermost/command.rb
@@ -0,0 +1,10 @@
+module Mattermost
+  class Command < Client
+    def create(params)
+      response = json_post("/api/v3/teams/#{params[:team_id]}/commands/create",
+        body: params.to_json)
+
+      response['token']
+    end
+  end
+end
diff --git a/lib/mattermost/session.rb b/lib/mattermost/session.rb
index fb8d7d97f8a..f0ce51d6a71 100644
--- a/lib/mattermost/session.rb
+++ b/lib/mattermost/session.rb
@@ -1,5 +1,10 @@
 module Mattermost
-  class NoSessionError < StandardError; end
+  class NoSessionError < StandardError
+    def message
+      'No session could be set up, is Mattermost configured with Single Sign on?'
+    end
+  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.
   #
@@ -30,6 +35,8 @@ module Mattermost
 
       begin
         yield self
+      rescue Errno::ECONNREFUSED
+        raise NoSessionError
       ensure
         destroy
       end
diff --git a/lib/mattermost/team.rb b/lib/mattermost/team.rb
new file mode 100644
index 00000000000..784eca6ab5a
--- /dev/null
+++ b/lib/mattermost/team.rb
@@ -0,0 +1,7 @@
+module Mattermost
+  class Team < Client
+    def all
+      json_get('/api/v3/teams/all')
+    end
+  end
+end