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.
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
