Example of how to do a server side authorization and restricted access to Mercadolibre/Mercadolivre API using Flask in a single file.

auth.py

import os
import json
import requests as req
from flask import Flask, Response, redirect, request

app = Flask(__name__)

'''
Example of how to do a server side authorization and restricted access to Mercadoli[bre|vre] API using Flask in a sigle file.

Author: https://github.com/xspager

Documentation link: https://developers.mercadolibre.com/en_us/api-docs


requirements.txt

requests==2.19.1
Flask==1.0.2
python-dotenv==0.9.1


Go to http://applications.mercadolibre.com/ and create a new application, set Redirect URI to "http://localhost"

Now create a file .flaskenv with the information about the app:

FLASK_APP=<THIS_FILE>.py
FLASK_ENV=development

APP_ID = <YOUR_APP_ID>
SECRET_KEY = <YOUR_SECRET_KEY>


To run:

    flask run

TODO: 
    [ ] Document
    [ ] Store token and refresh tokens
    [ ] Only try to authenticate if can't make a request and after trying to refresh the token if present
'''

APP_ID = os.environ.get("APP_ID", default="")
SECRET_KEY = os.environ.get("SECRET_KEY", default="")


@app.route("/")
def index():
    '''
        Start page
    '''

    # you will need to change only here to the authorization endpoint for the right country
    url = "https://auth.mercadolivre.com.br/authorization?response_type=code&client_id={}&redirect_uri=http://localhost:5000/get_token".format(
        APP_ID
    )
    return redirect(url)


@app.route("/get_token")
def get_token():
    '''
        Other page
    '''
    token = request.args.get('code', '')

    if token is not '':
        url_template = 'https://api.mercadolibre.com/oauth/token?grant_type=authorization_code&client_id={}&client_secret={}&code={}&redirect_uri=http://localhost:5000/get_token'

        r = req.post(
            url_template.format(
                APP_ID,
                SECRET_KEY,
                token
            ),
            allow_redirects=False
        )

        new_token = r.json()['access_token']

        url_template = "https://api.mercadolibre.com/users/{user_id}?access_token={token}"

        url = url_template.format(user_id='me', token=new_token)

        r = req.get(url)

        return Response(
            json.dumps(r.json(), indent=4, sort_keys=True),
            mimetype='application/json'
        )

    return 'No token found'