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HTTP / Google Sheets For Digi XBee Cellular

Archive of my HTTP requests implementation for the Digi XBee Cellular Modem to interface with Google Sheets, utilizing Digi's XBee Python library. This was written for my senior capstone project, JAMES2: an autonomous river drifter. It took a lot of trial and error to figure a lot of this out, as it was difficult finding example code online. Hopefully by archiving this publicly, it can assist others in the future.

Background

Utilizing the Digi XBee Cellular with HTTP requests was inspired by this tutorial for a GET request on the Digi documentation. I learned how to form my own HTTP requests using this wonderful website. I've never utilized Google APIs before, so it took a good amount of digging to find an auth type that worked for a fully autonomous modality. I finally landed on OAuth2 through a service account authenticated via HTTP-REST.

For HTTPCellular(), I tended to to replicate the interface of the Python Requests library when possible, as this is the HTTP requests library I'm the most familiar with. This can be seen in send_request() where data, params, and headers are parameters passed as dictionaries, similar to Python Requests.

Usage

Dependencies

To install the dependencies, in your virtual environment, run:

pip install -r requirements.txt

Classes

HTTPCellular()

Adds HTTP features to digi-xbee's CellularModem() class. On linux, requires user to be a part of the dialout group to access the USB ports. To do so, use the following command (found here):

sudo usermod -a -G dialout <username>

After performing this command, log out and back in.

CellularSpreadsheet()

Utilizes HTTPCellular() to update a Google Spreadsheet via REST requests. main() shows an example of it in action. Requires service_account.json to authenticate with Google. To get these credentials:

  1. Create a Google Cloud project.
  2. Create a Service Account within that project.
  3. Create and download a service account key (instructions for which are in the link for #2).
  4. Rename the .json file to service_account.json.
  5. Place service_account.json in the same directory as cellular.py.

Once the service account is created and credentials are downloaded, it must be added with edit access to the spreadsheet being edited, as well. This is done in the same way as sharing a spreadsheet with any other user.

Examples

GET request

Performing a GET request and printing the response.

http_device = HTTPCellular(timeout=10)
url = "https://httpbin.org/ip"
r, num_attempts = http_device.send_request(method="GET", 
                                           url=url)
print(r)

This is the same GET request as seen in the previously-referenced Digi tutorial, shown for comparison.

POST request

Performing a POST request and printing the response.

http_device = HTTPCellular(timeout=10)
url = "https://example.website"
token = "your-token-here"
headers = {"Authorization": f"Bearer {token}"}
data = {
    "james2": "rocks"
}

r, num_attempts = http_device.send_request(method="POST", 
                                           data=data,
                                           url=url,
                                           headers=headers)
print(r)

Example POST request with Bearer Authentication and body data.

Appending a Google Sheets spreadsheet

Appending james2,rocks to the cells A5,B5 of a spreadsheet and then printing the entirety of the spreadsheet.

spreadsheet_id = "your-spreadsheet-id-here"
spreadsheet = CellularSpreadsheet(spreadsheet_id=spreadsheet_id)

print("Updating spreadsheet...")
# values NEEDS TO BE A 2D ARRAY.
print(spreadsheet.append(values=[["james2", "rocks"]],range="A5:B5"))

# We don't need this for JAMES2 - this was just for testing / completeness
print("Getting the whole spreadsheet...")
print(spreadsheet.get())

As seen in main() of cellular.py.