Flask Backend

Code for Flask backend done at the workshop held on Feb 5, 2017.

Covers basic requests, querying from file and database.

Folder structure

• app
  • __init__.py
  • data
    • univ.db
    • people.json
  • api.py
• app.json
• Procfile
• requirements.txt
• run.py
• runtime.txt

run.py

#!usr/bin/python
from app import app
app.run(debug = True)

app/__init__.py

from flask import Flask  	# import Flask
app = Flask(__name__)		# Our app is an instance of Flask
from app import api		# Import API here, more files can be imported here

app/api.py

• Imports

   from app import app
   from flask import jsonify, request
   
   import json
   import time
   import sqlite3

• Data fromatter

   # Returns standard JSON formatted object with data, message and response code.
   def dataFormatter(code, message, data):
   resp = jsonify({
   	'code': code,
   	'message': message,
   	'data': data
   })
   resp.status_code = code
   return resp

• Routes without database

  • Example route

     # Returns the square of a passed number
     # Example, 
     @app.route('/number/<num>', methods=['GET'])

def square_method(num): try: sq = int(num) * int(num) ret = "Square of " + num + " is " + str(sq) + "." return dataFormatter(200, "Success.", ret) except: ret = "Error: Pass a number." return dataFormatter(400, "Bad request.", ret) ```

- For particulars

```python
@app.route('/<name>', methods=['GET', 'PUT', 'DELETE'])
def personParticular(name):

	# http://localhost:5000/The%20Doctor
	# cause I'm too lazy to edit the json for numeric keys :P

	# put
	if request.method == 'PUT':
		ptodelete = {}
		for person in data:
			if person['name'] == name:
				ptodelete = person
		if ptodelete in data:
			data.remove(ptodelete)
		ptoins = json.loads(request.form.get('data', ''))
		data.append(ptoins)
		saveFile()
		return dataFormatter(200, "Put successful", ptoins)

	# delete
	if request.method == 'DELETE':
		ptodelete = {}
		for person in data:
			if person['name'] == name:
				ptodelete = person
		if ptodelete in data:
			data.remove(ptodelete)
			saveFile()
			return dataFormatter(200, "delete successful", data)
		return dataFormatter(404, "Not found", [])

	# get
	if request.method == 'GET':
		psearch = {}
		for person in data:
			if person['name'] == name:
				psearch = person
		if psearch in data:
			return dataFormatter(200, "Person found", psearch)
		return dataFormatter(404, "Not found", [])

```