How to do a normal functions in python flask without a route and return the results of this process using a route?

Question

The app is loading the "links_submit.html" which has a field where you can write a link, like for example (www.google.com) and you submit it, then the app is receiving this URL as HTTP Post and redirecting to another page "post_response.html" which contains a simple html for feedback with the word "Ok". Then I want to do a process with this link (crawl google and search for a specific thing) and after finish this process, automatically redirect from the "post_reponse.html" to another page to show the results I have extracted from google. Now I'm not sure how say to my app on flask: "Ok now lets use a normal function (not route) like for example:

def loadpage(link_sent_by_the_http post):
   res = requests.get('www.google.com')

Imagine that after load the page I also extract some html tag on google and after finish this process I want to redirect the page "post_respose.html" with the "ok" to a new html page which contains the html tag extracted from google. Please note I know how to load the page google and extract what I want, but I don't know how to insert this function/process in the middle of Flask and then redirect from a normal html with "ok" for a new route with the results I have extracted.

import requests
from flask import Flask, render_template, request, url_for

app = Flask(__name__)

@app.route('/test')
def form():
   return render_template('links_submit.html')

@app.route('/links/', methods=['POST'])
def links():
    links=request.form['links']
    return render_template('post_response.html')

Intern Process (Load the received link > Extract what I want)
and then redirect the "post_response.html" to another "html" which will
contain the results that I have extracted) 

if __name__ == '__main__':
  app.run(debug=True)

Answer 1

Two ways to do it-

Create a python file say webfunctions.py and put your function in this file. e.g. -

def inc(x):
    return int(x) + 1

Now in your flask app file, you can import the whole file or just the function-

from webfunctions import inc

@app.route('/whatsnext/', methods=['POST'])
def waiting():
    curVal=request.form['x']
    nextVal = inc(curVal)
    return render_template('post_response.html', nextVal=nextVal)

or else, you may declare your definitions at the top of your flask app file. Like below -

import requests
from flask import Flask, render_template, request, url_for

def inc(x):
    return int(x) + 1


@app.route('/whatsnext/', methods=['POST'])
def waiting():
    curVal=request.form['x']
    nextVal = inc(curVal)
    return render_template('post_response.html', nextVal=nextVal)