Native uploader for the photogallery POST /upload endpoint. Pick or share a photo, add a caption and date, post. Credentials are entered once and sealed with a key held in the Android Keystore.

The server is not modified by this app. Everything it needs, it does client side.

Build

cd android
nix develop          # Android SDK 36, build-tools 36.0.0, JDK 17, gradle
gradle wrapper       # first time only, generates ./gradlew
./gradlew assembleDebug
adb install -r app/build/outputs/apk/debug/app-debug.apk

The dev shell exports ANDROID_HOME, JAVA_HOME and a GRADLE_OPTS that points AGP at the nix-provided aapt2. Without that last one AGP downloads a generic-linux aapt2 from Maven which will not run on NixOS.

Release signing

app/build.gradle.kts wires up a release signing config only when android/keystore.properties exists. Both that file and *.jks are gitignored — keep the keystore outside the repo and back it up somewhere you will still have in five years, because losing it means you can never upgrade an installed build in place.

mkdir -p ~/keys
keytool -genkeypair -v \
  -keystore ~/keys/photogallery-release.jks \
  -alias photogallery \
  -keyalg RSA -keysize 4096 -validity 10000

Then write android/keystore.properties:

storeFile=/home/you/keys/photogallery-release.jks
storePassword=…
keyAlias=photogallery
keyPassword=…

./gradlew assembleRelease

Without keystore.properties the release build still runs, it just comes out unsigned.

How it maps onto the server

Server behaviour	What the app does about it
Slug derived from the uploaded filename	Sends `yyyy-MM-dd-HHmmss.jpg`, generated once at enqueue
Same filename overwrites the same post	Reused across retries, which makes retries idempotent
Uploaded file published verbatim as "full size"	Strips EXIF, including GPS, before upload
Extension check rejects HEIC	Converts HEIC to JPEG; JPEG and PNG pass through losslessly
nginx `client_max_body_size 20M`	Steps quality, then resolution, if the result exceeds 18 MiB
Thumbnailer ignores EXIF orientation	Bakes rotation into the pixels rather than relying on the tag
nginx only proxies `/upload`, so `/health` 404s	Tests credentials with `GET /upload` instead
Replies `uploaded <slug>.jpg` in plain text	Parses that into `<base>/photo/<slug>/` for the "Open" link