Implemented dynamic parameters in MQTT payloads

Author: andzeil

CHANGELOG

@@ -1,3 +1,7 @@
+# Version 0.1.2
+[Chore] Updated depencies and build tooling
+[Feature] Implemented dynamic parameters in MQTT payloads
+
 # Version 0.1.1
 [Fix] Makefile fixed to build language files and icons within the build process
 [Feature] If the user wants SSL/TLS but doesn't provide a server certificate, try to fetch it automatically from the server

README.md

@@ -69,6 +69,18 @@ column. Should you need to add some command line parameters to the executable yo
 **Command line arguments** column. Look into the chapter [Integrating with Home Assistant](#integrating-with-home-assistant)
 for some example.
 
+Since **Version 0.1.2** there's a new feature for Power Users: It's parameters. With parameters, you can easily pass dynamic
+command line arguments to the command you want to run. The process is quite straight-forward:
+
+Set up the MQTT Payload like this: `{"command":"notify","args":"test", "param1":"test1", "param2":"test2"}`.
+
+You can then use `$X` in the **Command line arguments** column. `$X` would be replaced by
+the content of `paramX` within the payload. In our example if you put `$1 $2` into the **Command line arguments** column it
+will be replaced with `test1 test2` once the above MQTT payload is received.
+
+Should you have, e.g. `$3` defined in the **Command line arguments**, but the MQTT payload does not contain `param3`, `
+$3` will be removed from the command line arguments automatically, in order to not be passed to the command you want to run.
+
 ## Logs tab
 
 ![Logs](docs/assets/logs-tab.png)

src/easy_mqtt_handler/util/MQTTWorkerThread.py

@@ -10,6 +10,7 @@
 import gettext
 import json
 import os
+import re
 from ssl import SSLError, SSLZeroReturnError
 
 from PyQt5.QtCore import QThread, pyqtSignal
@@ -89,12 +90,26 @@ def router(self, data):
         mqtt_command = data.get("command")
         mqtt_arg = data.get("args")
 
+        # gather parameters delivered by the MQTT payload
+        i = 1
+        mqtt_params = []
+        while data.get("param" + str(i)) is not None:
+            mqtt_params.append(data.get("param"+(str(i))))
+            i += 1
+
         if mqtt_command is not None:
             self.add_log_line.emit(_("Received command \"{0}\" with argument \"{1}\".").format(mqtt_command, mqtt_arg))
 
         command_to_run = find_command_to_run(mqtt_command, mqtt_arg)
         command_line_args = find_command_line_arguments(mqtt_command, mqtt_arg)
 
+        # replace $X with paramX
+        for i, mqtt_param in enumerate(mqtt_params):
+            command_line_args = command_line_args.replace("$"+str(i+1), mqtt_param)
+
+        # remove remaining $X items (those who don't have a matching paramX provided by the MQTT payload
+        command_line_args = re.sub("\\$[0-9]*", "", command_line_args)
+
         if command_to_run is not None:
             # when there are spaces in the given command we should set it in quotes
             if ' ' in command_to_run: