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Flask Vue.js Integration Tutorial

Michael Bukachi on May 24, 2019

This tutorial answers the question, "How do I integrate Vue.js with Flask?" Since you are reading this tutorial, I assume that you know that Flask ...
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cynthiakamau profile image
CynthiaKamau •

This is my application structure, and every time i try to access the routes with blueprints i get this error:

return self.view_functionsrule.endpoint
TypeError: get() missing 1 required positional argument: 'self'

The routes are in this format :
api.add_resource(TrayResource, '/tray', '/trays')
api.add_resource(RackResource, '/rack', '/racks')

Should i add the blueprints and register them in the init file ad well?

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michaelbukachi profile image
Michael Bukachi •

Hello,
Do you mind sharing the code in TrayResource or RackResource?

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cynthiakamau profile image
CynthiaKamau •

from flask import current_app, request, Blueprint, render_template
from flask_jwt_extended import jwt_required
from flask_restful import Api, fields, marshal, reqparse

from api.models.database import BaseModel
from api.models.tray import Tray
from api.resources.base_resource import BaseResource
from api.utils import format_and_lower_str, log_create, log_duplicate, log_update, log_delete, non_empty_string, \
has_required_request_params

tray_bp = Blueprint('tray_bp', 'tray_page', template_folder='templates')

class TrayResource(BaseResource):
fields = {
'number': fields.Integer,
'rack.number': fields.Integer,
'code': fields.String
}

@tray_bp.route('/tray')
def get(self):
    if request.headers.get('code') is not None:
        code = format_and_lower_str(request.headers['code'])()
        tray = TrayResource.get_tray(code)
        data = marshal(tray, self.fields)
        return render_template('index.html')
        #return BaseResource.send_json_message(data, 200)
    else:
        trays = Tray.query.all()
        data = marshal(trays, self.fields)
        return BaseResource.send_json_message(data, 200)

@jwt_required
def post(self):
    args = TrayResource.tray_parser()
    rack = int(args['rack'])
    number = int(args['number'])
    code = format_and_lower_str(args['code'])()

    if not Tray.tray_exists(code):
        try:
            tray = Tray(rack_id=rack, number=number, code=code)
            BaseModel.db.session.add(tray)
            BaseModel.db.session.commit()
            log_create(tray)
            return BaseResource.send_json_message("Added new tray", 201)

        except Exception as e:
            current_app.logger.error(e)
            BaseModel.db.session.rollback()
            return BaseResource.send_json_message("Error while adding tray", 500)
    log_duplicate(Tray.query.filter(Tray.code == code).first())
    return BaseResource.send_json_message("Tray already exists", 500)

@jwt_required
@has_required_request_params
def put(self):
    code = format_and_lower_str(request.headers['code'])()
    tray = TrayResource.get_tray(code)
    if tray is not None:
        args = TrayResource.tray_parser()
        rack = int(args['rack'])
        number = int(args['number'])
        code = format_and_lower_str(args['code'])()

        if rack != tray.rack_id or number != tray.number or code != tray.code:
            try:
                tray.rack_id = rack
                tray.number = number
                tray.code = code
                BaseModel.db.session.commit()
                log_update(tray, tray)  # todo: log old record
                return BaseResource.send_json_message("Updated tray", 202)

            except Exception as e:
                current_app.logger.error(e)
                BaseModel.db.session.rollback()
                return BaseResource.send_json_message("Error while adding tray. Another tray has that number", 500)
        return BaseResource.send_json_message("No changes made", 304)
    return BaseResource.send_json_message("Tray not found", 404)

@jwt_required
@has_required_request_params
def delete(self):
    code = format_and_lower_str(request.headers['code'])()
    tray = TrayResource.get_tray(code)

    if not tray:
        return BaseResource.send_json_message("Tray not found", 404)

    BaseModel.db.session.delete(tray)
    BaseModel.db.session.commit()
    log_delete(tray)
    return BaseResource.send_json_message("Tray deleted", 200)

@staticmethod
def tray_parser():
    parser = reqparse.RequestParser()
    parser.add_argument('rack', required=True)
    parser.add_argument('number', required=True)
    parser.add_argument('code', required=True, type=non_empty_string)

    args = parser.parse_args()
    return args

@staticmethod
def get_tray(code):
    return BaseModel.db.session.query(Tray).filter_by(code=code).first()
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michaelbukachi profile image
Michael Bukachi •

Are you using Flask-Restful or Flask-Restplus?

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cynthiakamau profile image
CynthiaKamau •

Flask-restful

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michaelbukachi profile image
Michael Bukachi •

If you are using Flask-Restful then you don't need to use blueprints. Also, remove this @tray_bp.route('/tray') line from your resource methods. For further questions, I'd suggest asking your question here or posting the question on stackoverflow.

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cynthiakamau profile image
CynthiaKamau •

Thanks

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ryuzakyl profile image
L •

Nice work!

I was attempting to deploy the Flask API (no Vue.js for now) based on the Flask part of this tutorial, but I'm having some issues. I'm rather new with Flask :(.

I activate my virtualenv, but when running 'flask run' I keep getting the same error:

Error: While importing "wsgi", an ImportError was raised:

Traceback (most recent call last):
File "/home/ubuntu/.virtualenvs/scraphat_env/lib/python3.6/site-packages/flask/cli.py", line 235, in locate_app
import(module_name)
File "/home/ubuntu/Documents/scraphat_api/wsgi.py", line 11, in
from app import create_app
File "/home/ubuntu/Documents/scraphat_api/app/init.py", line 4, in
from .factory import Factory
File "/home/ubuntu/Documents/scraphat_api/app/factory.py", line 8, in
from .config import config
ModuleNotFoundError: No module named 'app.config'

I've also tried yo serve the Flask app with gunicorn, and get the same error.

Is there something I'm missing? I'm sure that there must be something I'm not doing right.

Any help would be appreciated.

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michaelbukachi profile image
Michael Bukachi •

Hello. Thanks for the feedback :)
Can you confirm and check if the file config.py is present?

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ryuzakyl profile image
L •

Thank you very much for the quick response.

The file is indeed present. Next, I show my project directory structure.

.
├── app
│ ├── config.py
│ ├── factory.py
│ ├── init.py
│ ├── models
│ │ ├── base.py
│ │ ├── database.py
│ │ ├── datastore.py
│ │ └── init.py
│ ├── resources
│ │ ├── health.py
│ │ ├── init.py
│ │ └── measures.py
│ └── utils.py
├── pytest.ini
├── README.md
├── requirements.txt
├── settings.py
├── tests
│ ├── conftest.py
│ ├── init.py
│ ├── test_app.py
│ ├── test_models.py
│ ├── test_resources.py
│ └── utils.py
├── unit-tests.sh
└── wsgi.py

Thanks for all the help.

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michaelbukachi profile image
Michael Bukachi •

What do you get when you run python wsgi.py ?

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ryuzakyl profile image
L •

If I do:

. workon project_env
. cd /path/to/project/root
. python wsgi.py

I get the following:

Traceback (most recent call last):
File "wsgi.py", line 11, in
from app import create_app
File "/home/ubuntu/Documents/scraphat_api/app/init.py", line 4, in
from .factory import Factory
File "/home/ubuntu/Documents/scraphat_api/app/factory.py", line 8, in
from .config import config
ModuleNotFoundError: No module named 'app.config'

Thank you for the feedback

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mattiasjohnson profile image
mattiasJohnson •

If I understood correctly this tutorial shows how you use flask and python when the whole index.html is a vue element. I would like to integrate flask and vue and use vue only for a few divs on my page!

I have been able to get some vue functionality by using <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script> and defining some vue stuff directly in my script tags in the same html file. I would however like to be able to use Single File Components .vue files which doesn't work for my approach. I imagine I need to use vue create vueproject in my main directory but after that I'm clueless.

Do you have any ideas how to be able to implement vue with full functionality with flask and only embed the vue components in a few divs on my page?

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michaelbukachi profile image
Michael Bukachi • • Edited

It's the same approach. Here's an example of snippets from index.html and main.js

index.html:

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width,initial-scale=1.0">
    <link rel="icon" href="<%= BASE_URL %>favicon.ico">
    <title>web</title>
  </head>
  <body>
    <noscript>
      <strong>We're sorry but web doesn't work properly without JavaScript enabled. Please enable it to continue.</strong>
    </noscript>
    <div id="app1"></div>
    <div id="app2"></div>
    <!-- built files will be auto injected -->
  </body>
</html>

main.js:

import Vue from 'vue'
import App1 from './App1.vue'
import App2 from './App2.vue'

Vue.config.productionTip = false

new Vue({
  render: h => h(App1),
}).$mount('#app1')


new Vue({
  render: h => h(App2),
}).$mount('#app2')

Remember to build your vue files otherwise it won't work.

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ipv6_python profile image
Gregory Wendel • • Edited

Michael,
Thanks for the great tutorial. I followed your instructions and here are a few notes.
When using the versions below:
Centos 7
node --version
v12.14.1
npm -version
6.13.4
Below are some things I did to get this working
1 - Install postgres and postgres dev before running pip install -r requirements.txt
sudo yum install postgresql-server postgresql-contrib
2 - near the end of your instructions in vue.config.js I removed the line, " baseUrl: '', "
I had the following error before removing the line:
ERROR Invalid options in vue.config.js: "baseUrl" is not allowed

Thanks,
Greg

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michaelbukachi profile image
Michael Bukachi •

Hello, thanks for the info. Let me update the tutorial.

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bkairu5 profile image
Halafu •

Kazi poa owefu! Good stuff!

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annndrey profile image
Andrey Gonchar •

Nice work!
And what is the advantage of this method? Right now Flask is just serving Vue files.
What is the difference between serving Vue with Flask and with npm?

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michaelbukachi profile image
Michael Bukachi •

Flask can be used to create APIs which can be consumed by the Vue app. In a situation where you are not using flask, you would have to implement the API in a different framework, say ExpressJs and do integrations from there.

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annndrey profile image
Andrey Gonchar •

Thanks for the answer, but still not clear the advantages of this way.
Say you have a Flask with API and a Vue frontend. In your case if Flask fails for some reason, there wouldn’t be a way to inform the user that something is wrong, because Vue is served by Flask too and the end user wouldn’t see the client app.
I suggest to divide both front and backend on the server level. So if Flask fails, you’ll still have the ability to inform the end user that the client app has lost connection with the server.

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michaelbukachi profile image
Michael Bukachi •

This method is not meant to replace the conventional two-tier design where you have a web app running on it on server and an API on it's own server. I actually always use the two tier approach for major projects. It's easier to manage and maintain. I only use this method for small and hobby projects. Think of vue as a replacement for bootstrap and jquery in a web application.

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evgeniifedulov profile image
Evgenii Fedulov •

It's not integration. It's joke.

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hyungjunk profile image
hyungjunk •

Great Tutorial. I also want to know about flask integrated with vue and webpack that provides live reloading feature when change made on template files.(js, html or vue)

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michaelbukachi profile image
Michael Bukachi •

Thanks!
To use live reloading just run yarn serve or npm run serve. Every change will trigger a live reload. However, you will have to run yarn build or npm run build to integrate vue files with the flask ap[.