Send payload to my web application using http request

[sobercactus]

Hi everyone, I have retrieved msg.payload from my IOT sensors, and I wonder how I can send msg.payload to my flask web application using http request or other method.

Thank you.

[TotallyInformation]

Welcome to the forum. However, you've not really given us anything to go on. We have no context about your web application so can't really help.

[sobercactus]

Sorry about that, I have upload a screenshot of my flask application.

[kitori]

You can send the request node POSTing data to your server:

Example flow:

[{"id":"12fde2238ad56ee2","type":"http request","z":"94c514c2ac360b08","name":"","method":"POST","ret":"txt","paytoqs":"ignore","url":"http://127.0.0.1:1880/receive_power","tls":"","persist":false,"proxy":"","insecureHTTPParser":false,"authType":"","senderr":false,"headers":[],"x":370,"y":180,"wires":[["a09478c1b756579b"]]},{"id":"e442c220d9d3430d","type":"http in","z":"94c514c2ac360b08","name":"","url":"/receive_power","method":"post","upload":false,"swaggerDoc":"","x":220,"y":320,"wires":[["f53b16c3af14be08","0d1f3e05f092db78"]]},{"id":"98db9a79c6719e6a","type":"inject","z":"94c514c2ac360b08","name":"sensor data","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"{\"maschine_id\":\"1\",\"machine_power\":\"200\"}","payloadType":"json","x":190,"y":180,"wires":[["12fde2238ad56ee2"]]},{"id":"a09478c1b756579b","type":"debug","z":"94c514c2ac360b08","name":"debug 15","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","statusVal":"","statusType":"auto","x":540,"y":180,"wires":[]},{"id":"f53b16c3af14be08","type":"http response","z":"94c514c2ac360b08","name":"","statusCode":"","headers":{},"x":490,"y":320,"wires":[]},{"id":"0d1f3e05f092db78","type":"debug","z":"94c514c2ac360b08","name":"debug 16","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","statusVal":"","statusType":"auto","x":480,"y":360,"wires":[]},{"id":"f576842b9cde1189","type":"comment","z":"94c514c2ac360b08","name":"send post request","info":"","x":190,"y":140,"wires":[]},{"id":"575b9c1094810d37","type":"comment","z":"94c514c2ac360b08","name":"dummy server","info":"","x":190,"y":280,"wires":[]}]

you can read more about the request node here: https://cookbook.nodered.org/#http-requests

[sobercactus]

This is my setup.

I think in this case what I doing this POSTing the data from my web server to node red, which I should be doing the other way around.

[kitori]

Whats is the payload? The server send something back, but the http request node can't convert it to json.

You can set the request that it return a string:

can you see that the data ist ingested into your backend?

And your backend use the Object requests.form.machine_id for extracteing the data, so try sending this payload to the backend:

{
    "payload": {
        "form": {
            "maschine_id": "1",
            "machine_power": "200"
        }
    }
}

you can use the change node:

[{"id":"98db9a79c6719e6a","type":"inject","z":"94c514c2ac360b08","name":"sensor data","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"{\"maschine_id\":\"1\",\"machine_power\":\"200\"}","payloadType":"json","x":190,"y":180,"wires":[["751195e907674896"]]},{"id":"751195e907674896","type":"change","z":"94c514c2ac360b08","name":"","rules":[{"t":"move","p":"payload","pt":"msg","to":"payload.form","tot":"msg"}],"action":"","property":"","from":"","to":"","reg":false,"x":410,"y":180,"wires":[["12fde2238ad56ee2","c6d2425f68837d2b"]]}]

[sobercactus]

Thank you for your reply.

1. My msg.object is this:

{"topic":"servicelocation/1df4d811-cd15-44db-b358-1caa61cf055d/realtime","payload":{"totalPower":0,"totalReactivePower":9,"totalExportEnergy":2271,"totalImportEnergy":8426,"monitorStatus":0,"utcTimeStamp":1713851721210,"channelPowers":[{"ctInput":0,"power":0,"exportEnergy":2271,"importEnergy":8426,"phaseId":0,"current":0}],"voltages":[{"voltage":235,"phaseId":0}]},"qos":0,"retain":false,"_msgid":"e5ca5b187342aa1b"}

2. In my backend, I get error message like this:

192.168.137.116 - - [23/Apr/2024 18:22:40] "POST /receive_power HTTP/1.1" 500 -
Traceback (most recent call last):
File "C:\Users\shawn\OneDrive\Desktop\Unimelb-2024-SEM-1\old_code.venv\Lib\site-packages\flask\app.py", line 1488, in call
return self.wsgi_app(environ, start_response)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Users\shawn\OneDrive\Desktop\Unimelb-2024-SEM-1\old_code.venv\Lib\site-packages\flask\app.py", line 1466, in wsgi_app
response = self.handle_exception(e)
^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Users\shawn\OneDrive\Desktop\Unimelb-2024-SEM-1\old_code.venv\Lib\site-packages\flask\app.py", line 1463, in wsgi_app
response = self.full_dispatch_request()
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Users\shawn\OneDrive\Desktop\Unimelb-2024-SEM-1\old_code.venv\Lib\site-packages\flask\app.py", line 872, in full_dispatch_request
rv = self.handle_user_exception(e)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Users\shawn\OneDrive\Desktop\Unimelb-2024-SEM-1\old_code.venv\Lib\site-packages\flask\app.py", line 870, in full_dispatch_request
rv = self.dispatch_request()
^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Users\shawn\OneDrive\Desktop\Unimelb-2024-SEM-1\old_code.venv\Lib\site-packages\flask\app.py", line 855, in dispatch_request
return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args) # type: ignore[no-any-return]
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "c:\Users\shawn\OneDrive\Desktop\Unimelb-2024-SEM-1\old_code\package\code\server\server_app.py", line 1296, in receive_power
machine_list.get(machine_id).power_generate=int(machine_power)
^^^^^^^^^^^^^^^^^^
TypeError: int() argument must be a string, a bytes-like object or a real number, not 'NoneType'

3. In the debug panel in Node-Red, when I set the request that it returns a string, I was seeing the error message like above sending from my backend.

4. This is a modification of my code before all of the above happened.

5. I was not using send_power_test.py in this scenario, I was just trying to send the JSON object to this url: /receive_power.

[kitori]

Maybe your dic object is empty?

in this tutorial, you get the dic with the obj.json property. But im not a flask expert
https://sentry.io/answers/flask-getting-post-data/#json-data

from flask import Flask, request
# ...

@app.route('/json_example', methods=['POST'])
def handle_json():
    data = request.json
    print(data.get('name'))
    print(data.get('age'))
    return data

[sobercactus]

Thanks for your help kitori. You Node-red flow is of great help.

I have solved my problems. My orginial code is for receiving form data, not json object.

Have a good day.