ente/desktop/docs/dependencies.md
2024-05-15 13:59:10 +05:30

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# Dependencies
- [Electron](#electron)
- [Dev dependencies](#dev)
- [Functionality](#functionality)
## Electron
[Electron](https://www.electronjs.org) is a cross-platform (Linux, Windows,
macOS) way for creating desktop apps using TypeScript.
Electron embeds Chromium and Node.js in the generated app's binary. The
generated app thus consists of two separate processes - the _main_ process, and
a _renderer_ process.
- The _main_ process runs the embedded node. This process can deal with the
host OS - it is conceptually like a `node` repl running on your machine. In
our case, the TypeScript code (in the `src/` directory) gets transpiled by
`tsc` into JavaScript in the `build/app/` directory, which gets bundled in
the generated app's binary and is loaded by the node (main) process when the
app starts.
- The _renderer_ process is a regular web app that gets loaded into the
embedded Chromium. When the main process starts, it creates a new "window"
that shows this embedded Chromium. In our case, we build and bundle a static
export of the [Photos web app](../web/README.md) in the generated app. This
gets loaded by the embedded Chromium at runtime, acting as the app's UI.
There is also a third environment that gets temporarily created:
- The [preload script](../src/preload.ts) acts as a gateway between the _main_
and the _renderer_ process. It runs in its own isolated environment.
### Packaging
[Electron Builder](https://www.electron.build) is used for packaging the app for
distribution.
During the build it uses
[electron-builder-notarize](https://github.com/karaggeorge/electron-builder-notarize)
to notarize the macOS binary.
### Updates
[electron-updater](https://www.electron.build/auto-update#debugging), while a
separate package, is also a part of Electron Builder. It provides an alternative
to Electron's built in auto updater, with a more flexible API. It supports auto
updates for the DMG, AppImage, DEB, RPM and NSIS packages.
[compare-versions](https://github.com/omichelsen/compare-versions) is used for
semver comparisons when we decide when to trigger updates.
### Logging
[electron-log](https://github.com/megahertz/electron-log) is used for logging.
Specifically, it allows us to log to a file (in addition to the console of the
Node.js process), and also handles log rotation and limiting the size of the log
files.
### next-electron-server
This spins up a server for serving files using a protocol handler inside our
Electron process. This allows us to directly use the output produced by
`next build` for loading into our renderer process.
### Others
- [any-shell-escape](https://github.com/boazy/any-shell-escape) is for
escaping shell commands before we execute them (e.g. say when invoking the
embedded ffmpeg CLI).
- [auto-launch](https://github.com/Teamwork/node-auto-launch) is for
automatically starting our app on login, if the user so wishes.
- [electron-store](https://github.com/sindresorhus/electron-store) is used for
persisting user preferences and other arbitrary data.
## Dev
See [web/docs/dependencies#dev](../../web/docs/dependencies.md#dev) for the
general development experience related dependencies like TypeScript etc, which
are similar to that in the web code.
Some extra ones specific to the code here are:
- [shx](https://github.com/shelljs/shx) for providing a portable way to use
Unix commands in our `package.json` scripts. This allows us to use the same
commands (like `ln`) across different platforms like Linux and Windows.
- [@tsconfig/recommended](https://github.com/tsconfig/bases) gives us a base
tsconfig for the Node.js version that our current Electron version uses.
## Functionality
### Format conversion
The main tool we use is for arbitrary conversions is ffmpeg. To bundle a
(platform specific) static binary of ffmpeg with our app, we use
[ffmpeg-static](https://github.com/eugeneware/ffmpeg-static).
> There is a significant (~20x) speed difference between using the compiled
> ffmpeg binary and using the wasm one (that our renderer process already has).
> Which is why we bundle it to speed up operations on the desktop app.
In addition, we also bundle a static Linux binary of imagemagick in our extra
resources (`build`) folder. This is used for thumbnail generation on Linux.
On macOS, we use the `sips` CLI tool for conversion, but that is already
available on the host machine, and is not bundled with our app.
### AI/ML
[onnxruntime-node](https://github.com/Microsoft/onnxruntime) is used as the
AI/ML runtime. It powers both natural language searches (using CLIP) and face
detection (using YOLO).
[jpeg-js](https://github.com/jpeg-js/jpeg-js#readme) is used for decoding JPEG
data into raw RGB bytes before passing it to ONNX.
html-entities is used by the bundled clip-bpe-ts tokenizer for CLIP.
### Watch Folders
[chokidar](https://github.com/paulmillr/chokidar) is used as a file system
watcher for the watch folders functionality.
### ZIP
[node-stream-zip](https://github.com/antelle/node-stream-zip) is used for
reading of large ZIP files (e.g. during imports of Google Takeout ZIPs).