Replace okhttp with ktor (okhttp engine)

[ArnyminerZ]

Purpose

Migrate the current okhttp implementation to ktor.

Short description

• Added the ktor dependency.
• Remove unused okhttp dependencies.
• Migrated MockWebServer usages to Ktor's mock server, using a custom wrapper to simplify the structure.
• Simplified URLs in tests with the utility functions provided by ktor.
• The http engine for Ktor is injected using Hilt.

Checklist

• The PR has a proper title, description and label.
• I have self-reviewed the PR.
• I have added documentation to complex functions and functions that can be used by other modules.
• I have added reasonable tests or consciously decided to not add tests.

[Copilot]

Pull Request Overview

This PR migrates the HTTP networking implementation from OkHttp to Ktor with OkHttp as the underlying engine. This migration maintains the same underlying networking behavior while adopting Ktor's more modern Kotlin-first API.

• Replaces direct OkHttp client usage with Ktor HttpClient while keeping OkHttp as the engine
• Migrates test infrastructure from MockWebServer to Ktor's MockEngine with a custom wrapper
• Updates dependency injection to provide HttpClient through Hilt

Reviewed Changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
gradle/libs.versions.toml	Adds Ktor dependencies for core, mock, and OkHttp engine
app/build.gradle.kts	Replaces OkHttp dependencies with Ktor equivalents
app/src/main/java/at/bitfire/icsdroid/HttpClient.kt	Refactors singleton HttpClient to use Ktor with OkHttp engine and adds Hilt module
app/src/main/java/at/bitfire/icsdroid/CalendarFetcher.kt	Updates HTTP calls to use Ktor API instead of OkHttp
app/src/main/java/at/bitfire/icsdroid/model/ValidationUseCase.kt	Adds HttpClient dependency injection
app/src/main/java/at/bitfire/icsdroid/ProcessEventsTask.kt	Updates to use injected HttpClient
app/src/androidTest/java/at/bitfire/icsdroid/MockEngineWrapper.kt	New wrapper for Ktor MockEngine to simplify test setup
app/src/androidTest/java/at/bitfire/icsdroid/model/ValidationUseCaseTest.kt	Migrates from MockWebServer to MockEngineWrapper
app/src/androidTest/java/at/bitfire/icsdroid/CalendarFetcherTest.kt	Updates test infrastructure to use Ktor MockEngine

Comments suppressed due to low confidence (3)

gradle/libs.versions.toml:29

• Ktor version 3.2.1 does not exist. The latest stable version of Ktor is 2.3.x series. Please use a valid Ktor version like "2.3.12" or check the official Ktor releases.

ktor = "3.2.1"

app/src/main/java/at/bitfire/icsdroid/HttpClient.kt:28

• [nitpick] The alias 'AppHttpClient' is confusing since it's aliasing the same class being defined. Consider using a more descriptive name or removing the alias if not needed.

import at.bitfire.icsdroid.HttpClient as AppHttpClient

app/src/androidTest/java/at/bitfire/icsdroid/MockEngineWrapper.kt:28

• [nitpick] The fallback response uses HttpStatusCode.NotImplemented which may not clearly indicate the actual issue (empty queue). Consider using a more descriptive status code or error message for debugging test failures.

            respond("No more responses", HttpStatusCode.NotImplemented)

[sunkup]

Nice! A few minor style comments. Feel free to ask or discard if you don't agree.

[sunkup]

OK 👍