polymny / Polymny

Polymny is a web based tool for easy production of educational videos.
You just need some slides in PDF and web browser!

This project consists in a backend written in rust and a front end in elm.

Table of contents

• Building
  • Building the client
  • Building the server
    • Installating Rust
    • Setting up the database
    • Configuring the server
• Running
• Developping

Building

The following sections explain how to build the client and the server.

Client

You'll need to intall elm in order to be able to build the client.

We recommend that you install elm with nvm.

Once elm is installed, you should be able to run make client-dev in the root of the repository to build the client.

Server

External packages

Install the following package before rust compilation:

sudo apt install libpoppler-glib-dev

Install Rust

You'll need to install rust-nightly in order to be able to build the server. We recommend that you install rust with rustup, so you can install rust nightly by running rustup toolchain add nightly.

You have three tways to build the server with nightly:

• you can simple run make server-dev at the root of the directory,
• if you feel more confortable with using cargo, you can go to the server directory, run rustup override set nightly, and then you'll be able to cargo build freely,
• or you can cargo +nightly build in the server directory.

Database setup

The server requires a postgresql database. The best way is to create a postgres user and a database for it. On most operating systems, you need to use the postgres user:

sudo su postgres

Once that's done, you can create a user and enter its password like this:

createuser -P <username>

and then, create a database for the user:

createdb <dbname> -O <username>

You can then run

exit

to get back to your normal user.

Matting

Matting is the process of background removal when the speaker is not in front of a green screen. In order to enable matting, certain steps must be done:

• the repository must be cloned at the same level where polymny is:

  git clone https://gitlab.enseeiht.fr/tforgione/Background-Matting
  

  (this step may take a little time because it also downloads the network)

• you also need an anaconda environment. Anaconda must be installed in ~/.anaconda3. You then create the environment for the background matting:

  conda create --name back-matting python=3.6
  conda activate back-matting
  

• you need to install Cuda 10.0. You need to export some variables for the server to be able to find cuda, e.g., if your cuda is in /usr/local/cuda-10.0, you can do

  export LD_LIBRARY_PATH=/usr/local/cuda-10.0/lib64
  export PATH=$PATH:/usr/local/cuda-10.0/bin
  

• you can then install the dependencies of the background matting software:

  conda install pytorch=1.1.0 torchvision cudatoolkit=10.0 -c pytorch
  pip install tensorflow-gpu==1.14.0
  pip install -r requirements.txt
  

Configuration

Once you've created the database, you need to write the configuration file. This file should be in server/Rocket.toml and should define some parameters. Here is an example of a minimal configuration file for development:

[development]
root = "http://localhost:8000"
secret_key = "eH/ZsKc5sJMD1/yr2HliA1XPlB3v6aT0Gv9pcRwQaYs="

[global.databases.database]
url = "postgres://<username>:<password>@localhost:5432/<dbname>"

A secret key can be generated by running openssl rand -base64 32.

Also, if you want to enable the background matting, you need to add the following variable to the development section of your Rocket.toml:

matting_enabled = true

The last thing that needs to be done is it initialize the database. For this, you will need diesel_cli. You can install it like so:

cargo install diesel_cli --no-default-features --features postgres

Once diesel_cli is installed, you will be able to initialize the database by running:

diesel migration run --database-url <database-url>

Mailer configuration

If you want, you can also configure the mailer in the server/Rocket.toml file. Doing so allows the server to send email, and thus, to verify users email. Here is a template of mailer configuration:

[global]
mailer_enabled = true
mailer_host = "<smtp-server-url>"
mailer_user = "<user-for-smtp-auth>"
mailer_password = "<password-for-smtp-auth>"
mailer_from = "<from-header-of-email>"

Running

Once you've built and configured everything, you just go to the server directory, and you run cargo run or cargo +nightly run depending on whether you overrode the toolchain.

Developping

You can install elm-live and run make client-watch at the root of the repository. When a change will be made to the client, elm-live will rebuild the client, and it will serve a static server on port 7000. However, this is not what you want, you need to start the rust server by going in the server directory and running cargo build or cargo +nightly build, and test on localhost:8000.

The rust server will always serve the latest version of the static files, so you don't need to restart the rust server everytime if you only modified the client.