Tempo is a full-stack web application and a music sharing platform dedicated to electronic music inspired on SoundCloud.

• Live Application
• Application Wiki

• JavaScript
• HTML5
• CSS3
• SQL

• React
• Redux
• Node.js
• Wavesurfer.js
• Express.js
• Sequelize
• Bcryptjs
• PostgreSQL
• Amazon Web Services S3
• FontAwesome
• TailwindCSS
• Heroku

Below are instructions to run the application on a local development environment.

• Node.js
• PostgreSQL

1. Clone this repository

   git clone https://github.com/guipace/Tempo.git

2. Change directory

   cd Tempo && cd backend

3. Install node modules

   npm install

4. Create your own environment variables files (.env) based on the provided examples (.env.example) in the backend directory.

5. Create a user in your PostgreSQL that matches your environment variables configuration.

6. Use Sequelize to create the database

   npx dotenv sequelize-cli db:create

7. Apply migrations to the database

   npx dotenv sequelize-cli db:migrate

8. Seed the database

   npx dotenv sequelize db:seed:all

9. In another terminal, change directories into the frontend directory

   cd frontend

10. Install node modules

    npm install

11. Run backend application in first terminal

    npm start

12. Run the frontend application in second terminal

    npm start

13. The application should open in your default browser.

A challenge faced in the development of SoarView includes the following:

• In order to improve the user experience I wanted to have an audio player that persisted as the user navigated across the application and visually show a waveform representing the track being played. In order to have the waveform on both the persistent player and on the track page with a visual representation if audio is playing and at what point in the track it is, I had to synchronize two instances of the audio player. While according to the wavesurfer.js documentation it was not specifically intended for this use, I developed a solution that allowed for this by using React components and Redux for state management.

• Implementation of Wavesurfer.js library with integration with Redux to synchronize with two audio player instances and control state of audio track.

  const formWaveSurferOptions = (ref) => ({
      container: ref,
      waveColor: "#BFC0C0",
      progressColor: "#EA5C1F",
      cursorColor: "transparent",
      barWidth: 4,
      barRadius: 1,
      responsive: true,
      height: 50,
      normalize: true,
      partialRender: true,
      hideScrollbar: true,
  });
  
  export let wavesurfer;
  
  export function Player() {
      const dispatch = useDispatch();
      const sessionUser = useSelector(state => state.session.user);
      const currentTrack = useSelector(state => state.player.currentTrack);
      const isPlaying = useSelector(state => state.player.isPlaying);
      const waveformRef = useRef(null);
      wavesurfer = useRef(null);
      const [playing, setPlay] = useState(false);
      const [volume, setVolume] = useState(0.5);
  
      let url;
      if (currentTrack) {
          url = currentTrack.awsUrl;
      }
  
      if (!url) {
      url =
          "https://www.mfiles.co.uk/mp3-downloads/brahms-st-anthony-chorale-theme-two-pianos.mp3";
      }
  
      // Create new WaveSurfer instance on component mount and when url changes
      useEffect(() => {
          setPlay(false);
          const options = formWaveSurferOptions(waveformRef.current);
          wavesurfer.current = WaveSurfer.create(options);
          wavesurfer.current.load(url);
          wavesurfer.current.on("ready", function () {
              wavesurfer.current.play();
              setPlay(true);
  
              // Make sure object still available when file loaded
              if (wavesurfer.current) {
                  wavesurfer.current.setVolume(volume);
                  setVolume(volume);
              }
          });
  
      // Removes events, elements and disconnects Web Audio nodes when component unmounts
      return () => wavesurfer.current.destroy();
      }, [url]);
  
      useEffect(() => {
          setPlay(isPlaying);
      }, [isPlaying]);
  
      const handlePlayPause = () => {
          if (isPlaying) { dispatch(stopTrack()) }
          else { dispatch(playAudioTrack()) }
          wavesurfer.current.playPause();
      };
  
      const handleStop = () => {
          dispatch(stopTrack());
          dispatch(unloadTrack());
      }
  
      const onVolumeChange = (e) => {
          const { target } = e;
          const newVolume = +target.value;
          if (newVolume) {
              setVolume(newVolume);
              wavesurfer.current.setVolume(newVolume || 1);
          }
      };
  
      return (
          <>
              {sessionUser &&
              <>
                  <div id='placeholder-for-player' className='bottom-0 h-20 bg-space-cadet'></div>
                  <div className='fixed w-screen z-10 h-20 bottom-0 bg-space-cadet bg-opacity-80 px-10 text-silver flex flex-row items-center'>
                      <div className='w-1/6 flex flex-row items-center'>
                          <Button
                              onClick={handlePlayPause}
                              className='text-white hover:text-mandarin font-bold h-10 w-10 rounded-full focus:outline-none'
                          >
                              {!playing ? <i className="fas fa-play"></i> : <i className="fas fa-pause"></i>}
                          </Button>
                          <Button
                              onClick={handleStop}
                              className='text-white hover:text-mandarin font-bold h-10 w-10 mr-5 rounded-full focus:outline-none'
                          >
                              <i className="fas fa-stop"></i>
                          </Button>
                          <div className='flex flex-col items-center flex-grow mr-5'>
                              <div>Volume</div>
                              <input
                                  className="slider w-36 mt-2"
                                  type="range"
                                  id="volume"
                                  name="volume"
                                  min="0.01"
                                  max="1"
                                  step=".025"
                                  onChange={onVolumeChange}
                                  defaultValue={volume}
                              />
                          </div>
                      </div>
                      <div id="waveform" ref={waveformRef} className='flex-grow' />
                      <div className='w-3/12 pl-5 flex flex-row items-center'>
                          <div className='flex-initial'><img src={currentTrack.imageUrl} alt='Track' className='w-10 h-10 shadow-2xl rounded'></img></div>
                          <div className='flex flex-col pl-5'>
                              <div>{currentTrack.User.username}</div>
                              <div>{currentTrack.title}</div>
                          </div>
                      </div>
                  </div>
              </>
              }
          </>
      );
  }