Hello all,
For context to my issue, I have a Raspberry Pi successfully uploading pH, turbidity, and temperature sensor data to ThingSpeak using a basic program. I was asked to implement a way for the results to be uploaded even if there was no internet connectivity, so in Python, the results should save to a CSV file which will later be automatically uploaded when the program runs and has internet connectivity again. So, the logic is:
- If the Pi has internet, upload the sensor readings to ThingSpeak using the POST method. That's all.
- If the Pi does not have internet, save the readings to a CSV file.
- When the program is ran again, if the internet is still disconnected, it will save the readings to the CSV again by amending the file (not overwriting it).
- When the program is ran again, if the internet is connected, it will automatically upload the CSV file to ThingSpeak using the POST bulk-write CSV method.
I have been searching the web for example code on how to get the bulk CSV upload for ThingSpeak working in Python. Most of the people asking for help are using the JSON method or Arduino code, but the ones who are using POST and Python (like I will be) have fixed their own issue without really going into detail on how they fixed it. I have checked the API thoroughly, but it is still confusing to me, even after checking out the examples that were in the MATLAB (such as this one: https://uk.mathworks.com/help/thingspeak/continuously-collect-data-and-bulk-update-a-thingspeak-channel-using-a-raspberry-pi-board.html )
Let me say that I am still quite new to Python/ThingSpeak. I've done my best to try to understand how the single write process works and apply it to the bulk write process, but I'm just drawing a blank. I guess my main question is that the URL in the API doesn't make sense to me: https://api.thingspeak.com/channels/channel_id/bulk_update.csv
I understand I'm supposed to put my channel ID into the URL, but how does my CSV file data apply to the "bulk_update.csv" part of the URL? Am I supposed to read in the results of the CSV and insert them into the URL? Am I thinking about this the wrong way? For reference, here's the Python code I use to upload single entries (I cut out the parts of code that don't apply). Any help is greatly appreciated.
import http.client
import urllib
import time
import serial
#Assign ThingSpeak read API key to a variable
apiKey = 'XXXXXXXXX'
def readSensors(): #Read sensor data
(Code omitted, but it basically just grabs sensor data from the Arduino)
return pH, turbidity, temperature
def uploadReadings(): #ThingSpeak upload
pH, turbidity, temperature = readSensors()
params = urllib.parse.urlencode({'field1': pH, 'field2': turbidity, 'field3': temperature, 'key':apiKey})
headers = {"Content-type": "application/x-www-form-urlencoded","Accept": "text/plain"}
conn = http.client.HTTPConnection("api.thingspeak.com:80")
try:
print("Attempting to contact ThingSpeak")
conn.request("POST", "/update", params, headers)
response = conn.getresponse()
print ("Upload status: ", response.status, response.reason)
conn.close()
except:
print("Connection failed")
while True:
uploadReadings()
break
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