extopy-app

The Extopy mobile app, built with Kotlin Multiplatform and Compose Multiplatform. One shared codebase, two thin platform shells.

Modules

Module	What it is
shared	Everything: data, domain, presentation, DI. Compiles to an Android library and an iOS framework.
androidApp	The Android application — an Application that starts Koin and an Activity that hosts App().
iosApp	The Xcode project — a SwiftUI shell around MainViewController().

Layers

Inside shared, under com.extopy:

data/          how things are actually fetched and stored
  api/         the HTTP client (com.extopy:client) and where the session tokens live
  database/    Room: the local cache, its entities and DAOs
  mappers/     API responses <-> domain models, domain models <-> cached rows
  repositories/  the implementations
domain/        what the app is about, and nothing else
  models/      Post, User, Timeline… — no serialization, no HTTP, no SQL
  repositories/  the interfaces the rest of the app talks to
  usecases/    only the operations that decide something
presentation/  Compose: components, navigation, screens, theme, view models
di/            the Koin modules

The rule that matters: domain and presentation never import com.extopy.api.*, com.extopy.client.*, io.ktor.*, androidx.room.* or com.russhwolf.*. Everything the API returns is translated in data/mappers before it goes any further, so a change to the API contract stops at that boundary.

View models take repositories directly for plain reads; a use case exists only where there is real logic — signing in, signing out, flipping a like or a follow.

API

The models and the HTTP client come from extopy-backend, published to Maven Central as com.extopy:api and com.extopy:client. The client attaches the access token to every call and refreshes it on its own; the app only supplies a TokenStore saying where the tokens are kept — the keychain on iOS, a preferences file on Android.

Running against a local backend

Start extopy-backend on port 8080, then:

Android — build the local flavor, which points at 10.0.2.2:8080 (how the emulator reaches your machine) and is the only flavor allowed to talk over cleartext HTTP:

./gradlew :androidApp:installLocalDebug

iOS — in Xcode, edit the scheme and add the environment variable EXTOPY_ENV=local, then run a debug build. It points at localhost:8080. The variable is ignored in release builds, so it cannot ship by accident.

Tests

./gradlew :shared:testAndroidHostTest

Everything under commonTest runs there. The iOS test binary cannot be linked outside Xcode — the Sentry SDK it depends on is supplied by the Xcode project through SPM — so the shared tests run on the JVM, which exercises the same code.

Building

./gradlew :androidApp:assembleProductionDebug            # Android
./gradlew :shared:linkDebugFrameworkIosSimulatorArm64    # iOS framework, then build in Xcode