Implemented Node-RED backend, solves #88

platypush/backend/nodered/__init__.py

@@ -0,0 +1,47 @@
+import inspect
+import os
+import subprocess
+import sys
+
+from platypush.backend import Backend
+
+
+class NoderedBackend(Backend):
+    """
+    This backend publishes platypush actions to a Node-RED instance.
+    If you enable this backend on a host that runs Node-RED then a new block (platypush -> run) can be
+    used in your flows. This block will accept JSON requests as input in the format
+    ``{"type":"request", "action":"plugin.name.action_name", "args": {...}}`` and return the output
+    of the action as block output, or raise an exception if the action failed.
+
+    Requires:
+
+        * **pynodered** (``pip install pynodered``)
+    """
+
+    def __init__(self, port: int = 5051, *args, **kwargs):
+        """
+        :param port: Listening port for the local publishing web server (default: 5051)
+        """
+        super().__init__(*args, **kwargs)
+        self.port = port
+        self._runner_path = os.path.join(
+            os.path.dirname(inspect.getfile(self.__class__)), 'runner.py')
+        self._server = None
+
+    def on_stop(self):
+        if self._server:
+            self._server.terminate()
+            self._server = None
+
+    def run(self):
+        super().run()
+
+        self._server = subprocess.Popen([sys.executable, '-m', 'pynodered.server',
+                                         '--port', str(self.port), self._runner_path])
+
+        self.logger.info('Started Node-RED backend on port {}'.format(self.port))
+        self._server.wait()
+
+
+# vim:sw=4:ts=4:et:

platypush/backend/nodered/runner.py

@@ -0,0 +1,35 @@
+import json
+
+from pynodered import node_red
+from platypush.context import get_plugin
+
+
+# noinspection PyUnusedLocal
+@node_red(name='run', title='run', category='platypush', description='Run a platypush action')
+def run(node, msg):
+    msg = msg['payload']
+    if isinstance(msg, bytes):
+        msg = msg.decode()
+    if isinstance(msg, str):
+        msg = json.loads(msg)
+
+    assert isinstance(msg, dict) and 'action' in msg
+
+    if 'type' not in msg:
+        msg['type'] = 'request'
+
+    plugin_name = '.'.join(msg['action'].split('.')[:-1])
+    action_name = msg['action'].split('.')[-1]
+    plugin = get_plugin(plugin_name)
+    action = getattr(plugin, action_name)
+    args = msg.get('args', {})
+
+    response = action(**args)
+    if response.errors:
+        raise response.errors[0]
+
+    msg['payload'] = response.output
+    return msg
+
+
+# vim:sw=4:ts=4:et:

requirements.txt

@@ -184,3 +184,6 @@ croniter
 
 # Support for RST->HTML docstring conversion
 # docutils
+
+# Support for Node-RED integration
+# nodered

setup.py

@@ -248,6 +248,8 @@ setup(
         'cv': ['cv2', 'numpy'],
         # Support for the generation of HTML documentation from docstring
         'htmldoc': ['docutils'],
+        # Support for Node-RED integration
+        'nodered': ['pynodered'],
     },
 )