Firebase short URL GAE proxy prototype

app.yaml

runtime: python27
api_version: 1
threadsafe: true

handlers:
- url: /.*
  script: main.app

libraries:
- name: flask
  version: 0.12

main.py

import logging
import json
from flask import Flask, request, redirect
from google.appengine.api import urlfetch

app = Flask(__name__)

@app.route('/')
def hello():
    return 'Hello World!'

@app.route('/<shortcode>')
def code_redir(shortcode):
    # !!                            Customise / add domains here if this gae is to be used for redirecting as well
    if 'nexerq.cf' in request.url_root:
        return redirect('https://nexerq.page.link/' + shortcode)
    return 'invalid shortcode'

@app.route('/shorten')
def shorten():
    if not ('k' in request.args and 'n' in request.args and 'u' in request.args and 'd' in request.args):
        return 'Invalid request', 400
    if request.args['n'] != 'code_thing': # !!   Add secret code here as well if want or remove - don't want random people using my proxy for their own firebase
        return 'Invalid auth', 401
    payload = {
        'dynamicLinkInfo': {
            'dynamicLinkDomain': request.args['d'],
            'link': request.args['u'],
        },
        'suffix': {
            'option': 'SHORT'
        }
    }
    try:
        result = urlfetch.fetch(
            url='https://firebasedynamiclinks.googleapis.com/v1/shortLinks?key=' + request.args['k'],
            method=urlfetch.POST,
            validate_certificate=True, # https
            headers={ 'Content-Type': 'application/json' },
            payload=json.dumps(payload))
        if result.status_code != 200:
            return result.content, result.status_code
        data = json.loads(result.content)
        return data['shortLink']
    except urlfetch.Error:
        logging.exception('Fetch or parse error')
        return 'ISE Fetch error', 500


@app.errorhandler(500)
def server_error(e):
    logging.exception('Error')
    return '500 ISE', 500

notes.md

To shorten: GET /shorten with args.

• k = Firebase API key
• n = Secret code (if desired) to use the GAE API
• d = Shortlink domain
• u = URL to be shortened

Returns full shortened URL in plaintext with given domain.

Can replace the domain (https://.../) with custom domain if wanted (GAE domain if configured).

sharex_config.json

{
  "Name": "GAE Firebase DL proxy test",
  "DestinationType": "URLShortener",
  "RequestType": "GET",
  "RequestURL": "https://<appspot_url>/shorten",
  "Arguments": {
    "k": "<firebase_api_key>",
    "n": "<private_api_key>",
    "d": "<shortlink_domain>",
    "u": "$input$"
  },
  "RegexList": [
    "([^\/]+$)"
  ],
  "URL": "https://<custom_proxy_domain>/$1,1$"
}