FlaskAPI

API Training example

Context for this example

• presentation link https://docs.google.com/presentation/d/1_EYQG7vnZ1it93h2X80REfLTjgMAv1z9mcp4cw4sWZo/edit?usp=sharing

Assumptions

• Basic Python understanding
• Basic Flask understanding
• Basic HTTP and REST endpoints (GET, POST ...)
• Flask Restful for the API library

setup

• git clone this repo https://github.com/cmcc13/FlaskAPI.git
• setup a virtual env virtualenv venv
• open the virtual env source venv/bin/activate
• install libraries pip install requirements.txt

run examples

example 1 - simple API creation and call

• in a terminal run python test1.py
• in a browser go to localhost click the call api button (it fails)
• in another terminal run python app1.py
• in a browser go to localhost:5000 check that api is healthy
• in a browser go to localhost click the call api button (it returns api response)

example 2 - extend example 1 with argument passing

• in another terminal run python test2.py
• in a browser go to localhost click the call api button
• in a terminal run python app2.py
• in a browser go to localhost:5000 check that api is healthy

example 3 - google cloud function as an api

• setup:
  • get a google cloud trial account
  • go to default project
  • enable billing
  • enable cloud functions api
• go to cloud functions
• modify the default python function
  • select python 3.7 as the runtime
  • modify the function to do something useful
  • click create
• test it in a browser or postman
• copy the url to test3.py code
• in a terminal run python test3.py
• cleanup: delete your function to avoid ongoing costs

further reading

• microservices context https://martinfowler.com/articles/microservices.html
• REST principles https://restfulapi.net/
• for api testing https://www.getpostman.com/
• JSON https://developer.mozilla.org/en-US/docs/Learn/JavaScript/Objects/JSON
• Flask Restful library https://flask-restful.readthedocs.io/en/latest/
• alternatives to flask restful (google FlaskAPI, Django, GraphQL)
• Note that in Flask Restful reqparse is deprecated https://flask-restful.readthedocs.io/en/0.3.6/reqparse.html and they suggest using https://marshmallow.readthedocs.io/en/3.0/
• cloud serverless api's https://serverless.com/ https://aws.amazon.com/lambda/ https://cloud.google.com/functions/