In order for the server to be isolated from the rest of the computer, a Python virtualenv must be created.
There, all the project's dependencies will be installed and the server can be tested safely in development or debug modes.

To create a virtualenv, you must create a venv directory (already ignored by git):

$ mkdir venv

and assign the virtualenv to the created directory:

$ python3 -m virtualenv venv

To activate the venv, do:

$ . venv/bin/activate

or

$ source ./venv/bin/activate

Now your terminal should look like this:

(venv) $

Now you can work safely from inside the virtual environment. There you can install the necessary dependencies as well as run your flask app.

To deactivate the venv, do:

(venv) $ deactivate

Now your terminal should look as always:

$

In a virtualenv, dependencies are installed in the same way that in a normal environment:

(venv) $ pip install Flask

But, as mentioned earlier, the installed dependencies will only be available inside the venv. Just keep that in mind.

The dependencies that are currently being used throughout the project can be found in the requirements.txt file.
To install them, do:

(venv) $ pip install -r requirements.txt

When you add a dependency, in order for the requirements.txt file to be updated just do:

(venv) $ pip freeze > requirements.txt

Flask needs two environment variables in order to work.
You can export them with:

(venv) $ export FLASK_APP=run.py (venv) $ export FLASK_ENV=development

or store them in a .env file (already ignored by git).

Also, in order for the server endpoints to interact properly with Firebase, the following env var is needed:

(venv) $ export FS_BUCKET=<project's bucket>

which can also be exported or stored in a file.

And, in order for the server endpoints to interact properly with PubNub, the following env vars are needed:

(venv) $ export PN_SUBSCRIBE_KEY=<subscribe key>
(venv) $ export PN_PUBLISH_KEY=<publish key>
(venv) $ export PN_SECRET_KEY=<secret key>
(venv) $ export PN_SERVER_UUID=<server uuid>

which can also be exported or stored in a file.

Finally, run the server with:

(venv) $ flask run

To ensure the backend runs as expected, the whole set of included tests can be run at all times with

(venv) $ pytest

To measure the coverage of the tests, run:

(venv) $ coverage run -m pytest

You can either view the coverage report within the terminal:

(venv) $ coverage report

or see an HTML report in your browser:

(venv) $ coverage html

The report will be in htmlconv/index.html