lerkeveld-backend

Backend of the Lerkeveld website, providing an api to the Lerkeveld Underground application (see https://github.com/lerkeveld/lerkeveld-underground).

Development

Installation requirements:

• python3.8

Installation instructions:

git clone 'https://github.com/lerkeveld/lerkeveld-backend' .
cd lerkeveld-backend
python3.8 -m venv env
./env/bin/pip install -r requirements.txt
touch secret.py

Add following development configuration options to secret.py:

import os
basedir = os.path.abspath(os.path.dirname(__file__))

# flask
SECRET_KEY = 'secret'

# flask_sqlalchemy
SQLALCHEMY_DATABASE_URI = 'sqlite:///' + os.path.join(basedir, 'app.db')

# flask_jwt_extended
JWT_SECRET_KEY = SECRET_KEY
JWT_COOKIE_SECURE = False

# flask_cors
CORS_ORIGINS = ['http://localhost:3000']
CORS_SUPPORTS_CREDENTIALS = True

# flask_mail
# MAIL_SUPPRESS_SEND = False
MAIL_DEFAULT_SENDER = "[email protected]"

# mailinglist
MAIL_KOTBAR_ADMIN = ["[email protected]"]
MAIL_MATERIAAL_ADMIN = ["[email protected]"]

# kotbar reservations
TOKEN_KOTBAR_RESERVATIONS = 'secret'

# bem overview
TOKEN_BREAD_RESERVATIONS = 'secret'

Some optional configuration changes:

• Add your private IP address to CORS_ORIGINS to allow devices on your LAN to connect via the development version of the Lerkeveld Underground application.
• Add an email account (see https://stackoverflow.com/questions/37058567/configure-flask-mail-to-use-gmail) and uncomment the line with MAIL_SUPPRESS_SEND.
• Add your email address to MAIL_KOTBAR_ADMIN and MAIL_MATERIAAL_ADMIN.

Setup the database

For development, by default a SQLite database placed at the repositories root is used (see configuration). Create the database (from the repository root execute env/bin/python):

from app import db
db.create_all()

Initialize the database

Adding users

Add users to the database using a python shell (from the repository root execute env/bin/python):

from app import db
from app.models import User
user = User(
    first_name="Test",
    last_name="Test",
    email="[email protected]",
    room=0,
    corridor="N0"
)
db.session.add(user)
db.session.commit()

Adding material

Add material to the database using a python shell (from the repository root execute env/bin/python):

from app import db
from app.models import MaterialType
material1 = MaterialType(name='Beamer')
material2 = MaterialType(name='BBQ 1')
material3 = MaterialType(name='BBQ 2')
db.session.add(material1)
db.session.add(material2)
db.session.add(material3)
db.session.commit()

Adding bread weeks and types

Add bread weeks and types to the database using a python shell (from the repository root execute env/bin/python):

import datetime
from app import db
from app.models import BreadOrderDate, BreadOrder, BreadType
db.session.add(BreadType(name="wit brood", price=200))
db.session.add(BreadType(name="grijs brood", price=200))
db.session.add(BreadType(name="blauw brood", price=2000))
db.session.add(BreadType(name="melk", price=60))
db.session.commit()
db.session.add(BreadOrderDate(date=datetime.date.today() + datetime.timedelta(days=1))
db.session.add(BreadOrderDate(date=datetime.date.today() + datetime.timedelta(days=2))
db.session.add(BreadOrderDate(date=datetime.date.today() + datetime.timedelta(days=3))
db.session.add(BreadOrderDate(date=datetime.date.today() + datetime.timedelta(days=4))
db.session.add(BreadOrderDate(date=datetime.date.today() + datetime.timedelta(days=5))
db.session.commit()

Production (Apache)

Installation requirements:

• apache (with mod_fcgi enabled)
• python3.8

Installation instructions:

git clone 'https://github.com/lerkeveld/lerkeveld-backend' .
cd lerkeveld-backend
python3.8 -m venv env
./env/bin/pip install -r requirements.txt
touch secret.py

Add following production configuration options to secret.py:

# flask
SECRET_KEY =

# flask_sqlalchemy
SQLALCHEMY_DATABASE_URI =

# flask_jwt_extended
JWT_SECRET_KEY = SECRET_KEY
JWT_COOKIE_SECURE = True

# flask_cors
CORS_ORIGINS = []

# flask_mail
# MAIL_SUPPRESS_SEND = False

# mailinglist
MAIL_KOTBAR_ADMIN = []
MAIL_MATERIAAL_ADMIN = []

# kotbar reservations
TOKEN_KOTBAR_RESERVATIONS = 

# bem overview
TOKEN_BREAD_RESERVATIONS = 

Critical configuration changes:

• Change SECRET_KEY, SQLALCHEMY_DATABASE_URI (see later), TOKEN_KOTBAR_RESERVATIONS and TOKEN_BREAD_RESERVATIONS, the web server errors otherwise.
• Change JWT_COOKIE_SECURE to False if the API is served insecurly with HTTP.
• Add to CORS_ORIGINS the domain name (with protocol, e.g. https://lerkies.simonbos.me) or IP address of the webserver hosting the frontend.
• Add an email account (see https://stackoverflow.com/questions/37058567/configure-flask-mail-to-use-gmail) and uncomment the line with MAIL_SUPPRESS_SEND.
• Add the relevant email addresses to MAIL_KOTBAR_ADMIN and MAIL_MATERIAAL_ADMIN. Note: everytime this configuration changes, the webserver has to restart. As such, it is best practice to use editable email forwarders here.

Setup the database

PostgreSQL setup (recommended) (These steps should be made on the files hosted by Ulyssis, accessable via SSH)

1. General methodology:

   1. Install postgresql
   2. Add a new user
   3. Change password for user
   4. Add a new database
   5. Grant access from user to database on local connection (pg_hba.conf)

2. Change SQLALCHEMY_DATABASE_URI in config.py to 'postgresql://user:password@localhost/database'.

3. Create the database (execute following script from a python shell):

from app import db
db.create_all()

SQLite setup (not recommended)

Installation instructions (requires root priviliges):

1. Create a directory ($DATA_DIR) in which the sqlite database will be stored. Do not put this in the web root.

mkdir "$DATA_DIR"

2. Change the group of the $DATA_DIR directory to www-data:

sudo chgrp www-data "$DATA_DIR"

3. Change the permissions of the $DATA_DIR directory:

chmod g=rwx "$DATA_DIR"

4. Change SQLALCHEMY_DATABASE_URI in config.py to sqlite:///$DATA_DIR/app.db.
5. Create the database using following script from a python shell:

from app import db
db.create_all()

6. Change the group of the database to www-data:

sudo chgrp www-data "$DATA_DIR/app.db"

7. Change the permissions of the database:

chmod g=rw "$DATA_DIR/app.db"

Initialize the database

(see development)

Connect backend to the web root

0. Enable mod_fcgi:

sudo a2enmod mod_fcgi

1. Install python-flup6:

~/.env/bin/pip install flup6

2. Add the file app.fcgi to the webroot:

#!/home/user/.env/bin/python
import sys, os, os.path
from threading import Thread

this_file = os.path.realpath(__file__)

site_dir = '/home/user/lerkeveld-backend'
sys.path.insert(0, site_dir)
os.chdir(site_dir)

from flup.server.fcgi import WSGIServer
from app import app

def stat_thread():
    import time, os, signal
    start_mtime = os.stat(this_file).st_mtime
    while True:
        cur_mtime = os.stat(this_file).st_mtime
        if cur_mtime != start_mtime:
            os.kill(os.getpid(), signal.SIGTERM)
        time.sleep(1)

Thread(target=stat_thread).start()


class ScriptNameStripper(object):
    def __init__(self, app):
        self.app = app

    def __call__(self, environ, start_response):
        environ['SCRIPT_NAME'] = ''
        return self.app(environ, start_response)

app = ScriptNameStripper(app)

if __name__ == '__main__':
     WSGIServer(app).run()

Critical changes to the provided app.fcgi file:

• Change the absolute path of the shebang to the absolute path of the python interpreter of the virtual environment.
• Change site_dir to the absolute path of the lerkeveld-backend directory.

3. Add following lines to the .htaccess file at the webroot:

Options +ExecCGI
AddHandler fcgid-script .fcgi

RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^admin/(.*)$ app.fcgi/admin/$1 [QSA,L]
RewriteRule ^api/(.*)$ app.fcgi/api/$1 [QSA,L]
RewriteRule ^token/(.*)$ app.fcgi/token/$1 [QSA,L]