Add "ActionPlugin" interface

- Plugin for running a custom action

InvenTree/plugins/action/action.py

@@ -0,0 +1,87 @@
+# -*- coding: utf-8 -*-
+
+import plugins.plugin as plugin
+
+
+class ActionPlugin(plugin.InvenTreePlugin):
+    """
+    The ActionPlugin class is used to perform custom actions
+    """
+
+    ACTION_NAME = ""
+
+    @classmethod
+    def action_name(cls):
+        """
+        Return the action name for this plugin.
+        If the ACTION_NAME parameter is empty,
+        look at the PLUGIN_NAME instead.
+        """
+        action = cls.ACTION_NAME
+        
+        if not action:
+            action = cls.PLUGIN_NAME
+        
+        return action
+
+    def __init__(self, user, data=None):
+        """
+        An action plugin takes a user reference, and an optional dataset (dict)
+        """
+        plugin.InvenTreePlugin.__init__(self)
+
+        self.user = user
+        self.data = data
+
+    def perform_action(self):
+        """
+        Override this method to perform the action!
+        """
+        pass
+
+    def get_result(self):
+        """
+        Result of the action?
+        """
+
+        # Re-implement this for cutsom actions
+        return False
+
+    def get_info(self):
+        """
+        Extra info? Can be a string / dict / etc
+        """
+        return None
+
+    def get_response(self):
+        """
+        Return a response. Default implementation is a simple response
+        which can be overridden.
+        """
+        return {
+            "action": self.action_name(),
+            "result": self.get_result(),
+            "info": self.get_info(),
+        }
+
+
+class SimpleActionPlugin(ActionPlugin):
+    """
+    An EXTREMELY simple action plugin which demonstrates
+    the capability of the ActionPlugin class
+    """
+
+    PLUGIN_NAME = "SimpleActionPlugin"
+    ACTION_NAME = "simple"
+
+    def perform_action(self):
+        print("Action plugin in action!")
+
+    def get_info(self):
+        return {
+            "user": self.user.username,
+            "hello": "world",
+        }
+
+    def get_result(self):
+        return True