Build an SMS Sending Flask App

First, install dependencies. Check out this sample code and run pip install -r requirements.txt. At the very least, you’ll need to install Flask into your virtualenv.

Create a Client object and an empty Flask app. If you would like to create a 12 factor app, load in configuration from environment variables (check out the helper function in utils.py in the sample code).

The problem with loading in environment variables is that it can make running the app a little bit more difficult. Use the python-dotenv library to load a .env file. It copies the values into the env var dictionary, so you can get the values using getenv as you would normally.

from dotenv import load_dotenv
from flask import Flask, flash, redirect, render_template, request, url_for
import nexmo
 
from .util import env_var, extract_error
 
# Load environment variables from a .env file:
load_dotenv('.env')
 
# Load in configuration from environment variables:
VONAGE_API_KEY = env_var('VONAGE_API_KEY')
VONAGE_API_SECRET = env_var('VONAGE_API_SECRET')
VONAGE_NUMBER = env_var('VONAGE_NUMBER')
 
# Create a new Client object:
nexmo_client = nexmo.Client(
    api_key=VONAGE_API_KEY, api_secret=VONAGE_API_SECRET
)
 
# Initialize Flask:
app = Flask(__name__)
app.config['SECRET_KEY'] = env_var('FLASK_SECRET_KEY')