From b286a5e30cbf392ec79d955ac86c0cac12010fae Mon Sep 17 00:00:00 2001
From: Oliver Walters <oliver.henry.walters@gmail.com>
Date: Tue, 14 Apr 2020 01:17:44 +1000
Subject: [PATCH] Plugin framework

- Registers some very simple barcode plugins
---
 InvenTree/plugins/__init__.py          |  0
 InvenTree/plugins/barcode/__init__.py  |  0
 InvenTree/plugins/barcode/barcode.py   | 19 ++++++++++
 InvenTree/plugins/barcode/digikey.py   |  8 ++++
 InvenTree/plugins/barcode/inventree.py | 14 +++++++
 InvenTree/plugins/plugins.py           | 52 ++++++++++++++++++++++++++
 6 files changed, 93 insertions(+)
 create mode 100644 InvenTree/plugins/__init__.py
 create mode 100644 InvenTree/plugins/barcode/__init__.py
 create mode 100644 InvenTree/plugins/barcode/barcode.py
 create mode 100644 InvenTree/plugins/barcode/digikey.py
 create mode 100644 InvenTree/plugins/barcode/inventree.py
 create mode 100644 InvenTree/plugins/plugins.py

diff --git a/InvenTree/plugins/__init__.py b/InvenTree/plugins/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/InvenTree/plugins/barcode/__init__.py b/InvenTree/plugins/barcode/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/InvenTree/plugins/barcode/barcode.py b/InvenTree/plugins/barcode/barcode.py
new file mode 100644
index 0000000000..a2d3c6652e
--- /dev/null
+++ b/InvenTree/plugins/barcode/barcode.py
@@ -0,0 +1,19 @@
+# -*- coding: utf-8 -*-
+
+
+class BarcodePlugin:
+    """
+    The BarcodePlugin class is the base class for any barcode plugin.
+    """
+
+    # Override this for each actual plugin
+    PLUGIN_NAME = ''
+
+    def validate_barcode(self, barcode_data):
+        """
+        Default implementation returns False
+        """
+        return False
+
+    def __init__(self):
+        pass
diff --git a/InvenTree/plugins/barcode/digikey.py b/InvenTree/plugins/barcode/digikey.py
new file mode 100644
index 0000000000..2542fe964a
--- /dev/null
+++ b/InvenTree/plugins/barcode/digikey.py
@@ -0,0 +1,8 @@
+# -*- coding: utf-8 -*-
+
+from . import barcode
+
+
+class DigikeyBarcodePlugin(barcode.BarcodePlugin):
+
+    PLUGIN_NAME = "DigikeyBarcodePlugin"
diff --git a/InvenTree/plugins/barcode/inventree.py b/InvenTree/plugins/barcode/inventree.py
new file mode 100644
index 0000000000..f983487a41
--- /dev/null
+++ b/InvenTree/plugins/barcode/inventree.py
@@ -0,0 +1,14 @@
+# -*- coding: utf-8 -*-
+
+from . import barcode
+
+
+class InvenTreeBarcodePlugin(barcode.BarcodePlugin):
+
+    PLUGIN_NAME = "InvenTreeBarcodePlugin"
+
+    def validate_barcode(self, barcode_data):
+
+        print("testing")
+
+        return True
diff --git a/InvenTree/plugins/plugins.py b/InvenTree/plugins/plugins.py
new file mode 100644
index 0000000000..75815aded2
--- /dev/null
+++ b/InvenTree/plugins/plugins.py
@@ -0,0 +1,52 @@
+# -*- coding: utf-8 -*-
+
+import inspect
+import importlib
+import pkgutil
+
+# Barcode plugins
+import plugins.barcode as barcode
+from plugins.barcode.barcode import BarcodePlugin
+
+
+def iter_namespace(pkg):
+
+    return pkgutil.iter_modules(pkg.__path__, pkg.__name__ + ".")
+
+
+def get_modules(pkg):
+    # Return all modules in a given package
+    return [importlib.import_module(name) for finder, name, ispkg in iter_namespace(barcode)]
+
+
+def get_classes(module):
+    # Return all classes in a given module
+    return inspect.getmembers(module, inspect.isclass)
+
+
+def get_plugins(pkg, baseclass):
+    """
+    Return a list of all modules under a given package.
+
+    - Modules must be a subclass of the provided 'baseclass'
+    - Modules must have a non-empty PLUGIN_NAME parameter
+    """
+
+    plugins = []
+
+    modules = get_modules(pkg)
+
+    # Iterate through each module in the package
+    for mod in modules:
+        # Iterate through each class in the module
+        for item in get_classes(mod):
+            plugin = item[1]
+            if plugin.__class__ is type(baseclass) and plugin.PLUGIN_NAME:
+                plugins.append(plugin)
+
+    return plugins
+
+
+def load_barcode_plugins():
+
+    return get_plugins(barcode, BarcodePlugin)