JSON数据通过MQTT python接收了错误的格式

Question

I have a problem with receiving data over MQTT in Python.

I send from one script:

payload = '{"sensor":[{"name":"temp","value":"%s"}]}' % str(read_temp())
print payload
print is_json(payload) 
client.publish("xxxxx/xxxxx", json.dumps(payload))

and receive with another script:

def on_message(client, userdata, msg):
    message = str(msg.payload)
    if is_json(message): 
        jsonResponse=json.loads(json.dumps(message))
        print jsonResponse

Output:

"{\"sensor\":[{\"name\":\"temp\",\"value\":\"23.0\"}]}"

I try play with loads and dumps but nothing helps.

Answer 1

You double escaping the message, once at publish time and once when it's received with json.dumps . Remove the extra from the subscriber:

def on_message(client, userdata, msg):
    message = str(msg.payload)
    if is_json(message): 
        jsonResponse=json.loads(message)
        print jsonResponse