[FIXED] flask application brings error requests.exceptions.ConnectionError requests.exceptions.ConnectionError Max retries exceeded with url: /chain

Issue

Whenever i try to run my flask application I get this error:

requests.exceptions.ConnectionError
requests.exceptions.ConnectionError: HTTPConnectionPool(host='127.0.0.1', port=8000): 
Max retries exceeded with url: //chain (Caused by NewConnectionError('<urllib3.connection.HTTPConnection object at 0x000001EECEBA9E10>: 
Failed to establish a new connection: [WinError 10061] No connection could be made because the target machine actively refused it'))

My steps for running the application are: set FLASK_APP=hello

flask run

Can anyone help?

this is my view.py file

import datetime
import json

import requests
from flask import render_template, redirect, request

from app import app

# The node with which our application interacts, there can be multiple
# such nodes as well.
CONNECTED_NODE_ADDRESS = "http://127.0.0.1:8000/"

posts = []


def fetch_posts():
    """
    Function to fetch the chain from a blockchain node, parse the
    data and store it locally.
    """
    get_chain_address = "{}/chain".format(CONNECTED_NODE_ADDRESS)
    response = requests.get(get_chain_address)
    if response.status_code == 200:
        content = []
        chain = json.loads(response.content)
        for block in chain["chain"]:
            for tx in block["transactions"]:
                tx["index"] = block["index"]
                tx["hash"] = block["previous_hash"]
                content.append(tx)

        global posts
        posts = sorted(content, key=lambda k: k['timestamp'],
                       reverse=True)


@app.route('/')
def index():
    fetch_posts()
    return render_template('index.html',
                           title='YourNet: Decentralized '
                                 'content sharing',
                           posts=posts,
                           node_address=CONNECTED_NODE_ADDRESS,
                           readable_time=timestamp_to_string)


@app.route('/submit', methods=['POST'])
def submit_textarea():
    """
    Endpoint to create a new transaction via our application.
    """
    post_content = request.form["content"]
    author = request.form["author"]

    post_object = {
        'author': author,
        'content': post_content,
    }

    # Submit a transaction
    new_tx_address = "{}/new_transaction".format(CONNECTED_NODE_ADDRESS)

    requests.post(new_tx_address,
                  json=post_object,
                  headers={'Content-type': 'application/json'})

    return redirect('/')


def timestamp_to_string(epoch_time):
    return datetime.datetime.fromtimestamp(epoch_time).strftime('%H:%M')

Solution

This could happen for various reasons. Maybe the port you are trying to run flask is being used from another application. Try the structure below to change the port that the flask is running.

from flask import Flask

app = Flask(__name__)

@app.route('/')
def index():
    return 'something'

app.run(host='127.0.0.1', port=5000)

Try to use different ports like 5000 or 8080.

Answered By - Ioannis Skaltsas