support/doc/development/server/code.md

   1 # Server code documentation
   2
   3 The server is a web server developed with [TypeScript](https://www.typescriptlang.org/)/[Express](http://expressjs.com).
   4
   5
   6 ## Technologies
   7
   8   * [TypeScript](https://www.typescriptlang.org/) -> Language
   9   * [PostgreSQL](https://www.postgresql.org/) -> Database
  10   * [Redis](https://redis.io/) -> Job queue/cache
  11   * [Express](http://expressjs.com) -> Web server framework
  12   * [Sequelize](http://docs.sequelizejs.com/en/v3/) -> SQL ORM
  13   * [WebTorrent](https://webtorrent.io/) -> BitTorrent tracker and torrent creation
  14   * [Mocha](https://mochajs.org/) -> Test framework
  15
  16
  17 ## Files
  18
  19 The server main file is [server.ts](/server.ts).
  20 The server modules description are in the [package.json](/package.json) at the project root.
  21 All other server files are in the [server](/server) directory:
  22
  23     server.ts -> app initialization, main routes configuration (static routes...)
  24     config    -> server YAML configurations (for tests, production...)
  25     scripts   -> Scripts files for npm run
  26     server
  27     |__ controllers  -> API routes/controllers files
  28     |__ helpers      -> functions used by different part of the project (logger, utils...)
  29     |__ initializers -> functions used at the server startup (installer, database, constants...)
  30     |__ lib          -> library function (WebTorrent, OAuth2, ActivityPub...)
  31     |__ middlewares  -> middlewares for controllers (requests validators, requests pagination...)
  32     |__ models       -> Sequelize models for each SQL tables (videos, users, accounts...)
  33     |__ tests        -> API tests and real world simulations (to test the decentralized feature...)
  34
  35
  36 ## Conventions
  37
  38 Uses [JavaScript Standard Style](http://standardjs.com/).
  39
  40 ## Architecture
  41
  42 The server is composed by:
  43
  44   * a REST API (relying on the Express framework) documented on http://docs.joinpeertube.org/api.html
  45   * a WebTorrent Tracker (slightly custom version of [webtorrent/bittorrent-tracker](https://github.com/webtorrent/bittorrent-tracker#server))
  46
  47 A video is seeded by the server with the [WebSeed](http://www.bittorrent.org/beps/bep_0019.html) protocol (HTTP).
  48
  49 ![Architecture scheme](/support/doc/development/server/upload-video.png)
  50
  51 When a user uploads a video, the REST API creates the torrent file and then adds it to its database.
  52
  53 If a user wants to watch the video, the tracker will indicate all other users that are watching the video + the HTTP url for the WebSeed.
  54
  55 ## Newcomers
  56
  57 The server entrypoint is [server.ts](/server.ts). Looking at this file is a good start.
  58 Then you can try to understand the [controllers](/server/controllers): they are the entrypoints of each API request.