Cake Protocol

At work there's this thing where if someone leaves the laptop unlocked and unattended, passerby colleagues will open teams and post cake on a random group on teams. Others will pile on with a wave of cake replies.

This small app called cakeprotocol puts an end to this. It uses uses the webcam and Haar cascades to detect if the user is in front of the laptop. I went with this approach instead of neural networks for power efficiency. The tool has a configurable poll interval and miss treshold to decide when to lock the screen.

Developed and tested on Linux. Should work on Mac and Windows too. If it doesn't feel free to open an issue or even better, a PR.

Build

The app uses Bazel and C++23.

READ

Some dependencies (OpenCV, protobuf) are heavy to compile and may cause out-of-memory errors. If that happens, limit parallelism by adding something like build --jobs=4 to user.bazelrc (create this file at the root of the repo) and re-run the build. Since builds are cached, it will continue from where it left off.

Release build

bazel build -c opt //src/main:main

Note: There's a :cakeprotocol alias that points to the //src/main:main.

Install

Copy the optimized binary somewhere in your PATH:

cp $(bazel cquery --output=files -c opt //src/main:main 2>/dev/null) <SOMEWHERE IN $PATH>/cakeprotocol

Run

bazel run //src/main:main

Generate compile_commands.json

bazel run //:refresh_compile_commands

Currently having problems with the refresh_compile_commands. For some reason it fails after having added opencv.

Update bazelrc presets

bazel run //tools:bazelrc.update