proxy: mqtt: allow arbitrary writes v1 PROPOSED

Jan Kundrát: 1
 proxy: mqtt: allow arbitrary writes

 2 files changed, 40 insertions(+), 4 deletions(-)

[PATCH] proxy: mqtt: allow arbitrary writes Export this patch

Since there are typically no server-side MQTT ACLs, this has to be
enabled explicitly.

There's some duplication of code between this implementation and the one
in the HTTP backend. The most straightforward way of fixing that is to
convert these early returns into proper exceptions, but I'm too lazy for
this and I'm gonna be using this feature tomorrow :).

Signed-off-by: Jan Kundrát <jkt@jankundrat.com>
---
 openswitcher_proxy/frontend_mqtt.py | 43 ++++++++++++++++++++++++++---
 proxy.toml                          |  1 +
 2 files changed, 40 insertions(+), 4 deletions(-)

diff --git a/openswitcher_proxy/frontend_mqtt.py b/openswitcher_proxy/frontend_mqtt.py
index 63538c6..ff0b23a 100644
--- a/openswitcher_proxy/frontend_mqtt.py
+++ b/openswitcher_proxy/frontend_mqtt.py
@@ -5,6 +5,7 @@ from functools import partial
 
 from .error import DependencyError
 from .frontend_httpapi import FieldEncoder
+import pyatem.command as commandmodule
 
 try:
     import paho.mqtt.client as mqtt
@@ -74,12 +75,46 @@ class MqttFrontendThread(threading.Thread):
     def on_mqtt_connect(self, flags, rc):
         self.status = 'running'
         logging.info(f'MQTT: connected ({rc})')
-        # TODO: enable once on_mqtt_message() works
-        # client.subscribe(f'atem/{userdata.hw_name}/#')
+        self.client.subscribe(f'atem/+/set/#')
 
     def on_mqtt_message(self, msg):
-        # TODO: propagate to the switcher, eventually
-        logging.debug(f'MQTT: msg: {msg.topic} {msg.payload}')
+        if not self.config.get('allow-writes', False):
+            logging.error('MQTT writes disabled')
+            return
+        parts = msg.topic.split('/')
+        if len(parts) != 4:
+            logging.error(f'MQTT: malformed command topic: {msg.topic}')
+            return
+        hw = parts[1]
+        if parts[0] != 'atem' or parts[2] != 'set':
+            logging.error(f'MQTT: malformed command topic: {msg.topic}')
+            return
+        if hw not in self.hw_name:
+            logging.error(f'MQTT: not handling writes for "{hw}"')
+            return
+        fieldname = parts[3]
+        classname = fieldname.title().replace('-', '') + "Command"
+        if not hasattr(commandmodule, classname):
+            logging.error(f'MQTT: unrecognized command {fieldname}')
+            return
+        arguments = json.loads(msg.payload)
+        if not isinstance(arguments, dict):
+            logging.error(f'MQTT: mailformed payload, needs a JSON dict')
+            return
+        for key in arguments:
+            try:
+                arguments[key] = int(arguments[key])
+            except:
+                pass
+        if 'source' in arguments:
+            inputs = self.threadlist['hardware'][hw].switcher.inputs
+            if arguments['source'] in inputs:
+                arguments['source'] = inputs[arguments['source']]
+        try:
+            cmd = getattr(commandmodule, classname)(**arguments)
+            self.threadlist['hardware'][hw].switcher.send_commands([cmd])
+        except Exception as e:
+            logging.error(f'MQTT: cannot write {fieldname}: {str(e)}')
 
     def get_status(self):
         if self.status == 'error':
diff --git a/proxy.toml b/proxy.toml
index bd6b213..1e55bf5 100644
--- a/proxy.toml
+++ b/proxy.toml
@@ -36,3 +36,4 @@ type = "mqtt"
 host = "localhost:1883"
 hardware = "mini"
 auth = false
+allow-writes = false
-- 
2.33.0