feat(android): publish an Obtainium app config with each release

.changeset/add-obtainium-app-config.md

@@ -0,0 +1,5 @@
+---
+default: patch
+---
+
+Publish an `obtainium.json` app config with every release so Android builds can be installed and auto-updated through Obtainium.

.github/workflows/tauri-build.yml

@@ -408,6 +408,33 @@ jobs:
             gh release upload "$TAG" "$f" --clobber
           done
 
+  obtainium:
+    name: Publish Obtainium config
+    needs: [setup-release, android]
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    permissions:
+      contents: write
+    env:
+      TAG: ${{ needs.setup-release.outputs.tag }}
+      VERSION: ${{ needs.setup-release.outputs.version }}
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          ref: ${{ needs.setup-release.outputs.ref }}
+          persist-credentials: false
+
+      - name: Generate obtainium.json
+        shell: bash
+        run: node scripts/obtainium-generate.js "$VERSION" "$TAG" obtainium.json
+
+      - name: Attach Obtainium config to release
+        shell: bash
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: gh release upload "$TAG" obtainium.json --clobber
+
   ios:
     name: Build iOS (AltStore/SideStore)
     needs: setup-release

README.md

@@ -13,6 +13,32 @@ The stable web app is available at [app.sable.moe](https://app.sable.moe/) and t
 
 You can also download our desktop app for Windows and Linux from [releases](https://github.com/SableClient/Sable/releases/latest). Release artifacts include build attestations, and desktop installations update automatically.
 
+## Android (Obtainium)
+
+Android APKs are published to every release, and [Obtainium](https://obtainium.imranr.dev) keeps them updated straight from GitHub. Each release also ships an `obtainium.json` app config. Use it for the nightly channel, where prereleases and date-based version tracking have to be enabled to follow the rolling `nightly` tag.
+
+### Stable
+
+<a href="https://intradeus.github.io/http-protocol-redirector?r=obtainium://add/https://github.com/SableClient/Sable"><img alt="Add to Obtainium" src="https://img.shields.io/badge/Add_to_Obtainium-6750A3?style=for-the-badge"></a>
+&nbsp;
+<a href="https://github.com/SableClient/Sable/releases/latest/download/obtainium.json"><img alt="App config" src="https://img.shields.io/badge/App_config-6B7280?style=for-the-badge"></a>
+&nbsp;
+<a href="https://github.com/SableClient/Sable/releases/latest"><img alt="Download APK" src="https://img.shields.io/badge/Download_APK-3DDC84?style=for-the-badge&logo=android"></a>
+
+### Nightly
+
+<a href="https://github.com/SableClient/Sable/releases/download/nightly/obtainium.json"><img alt="App config" src="https://img.shields.io/badge/App_config-6B7280?style=for-the-badge"></a>
+&nbsp;
+<a href="https://github.com/SableClient/Sable/releases/tag/nightly"><img alt="Download APK" src="https://img.shields.io/badge/Download_APK-3DDC84?style=for-the-badge&logo=android"></a>
+
+### Setup & install
+
+1. Install [Obtainium](https://github.com/ImranR98/Obtainium/releases/latest).
+2. For stable, tap the button above, or add `https://github.com/SableClient/Sable` by hand under **Add App**.
+3. For nightly, download the `obtainium.json` above and import it with **Import/Export → Import from file**.
+
+Android builds are produced by the `android` job in [`tauri-build.yml`](.github/workflows/tauri-build.yml), and the config by the `obtainium` job in the same workflow.
+
 ## iOS (AltStore / SideStore)
 
 Sable iOS builds are distributed as unsigned IPAs through [AltStore](https://altstore.io) and [SideStore](https://sidestore.io). Each release publishes both the IPA and an `altstore-source.json` manifest — stable builds to the [latest GitHub release](https://github.com/SableClient/Sable/releases/latest), nightly builds to the [`nightly` GitHub release](https://github.com/SableClient/Sable/releases/tag/nightly).

scripts/obtainium-generate.js

@@ -0,0 +1,63 @@
+#!/usr/bin/env node
+//MISE hide=true
+//MISE description="Generate obtainium.json for one-click app import"
+/* oxlint-disable no-console */
+
+import { writeFileSync } from 'node:fs';
+import { resolve } from 'node:path';
+import process from 'node:process';
+
+const version = process.argv[2];
+const tag = process.argv[3] || `v${version}`;
+const outputPath = process.argv[4] || 'obtainium.json';
+
+if (!version) {
+  console.error('Usage: node scripts/obtainium-generate.js <version> [tag] [output-path]');
+  process.exit(1);
+}
+
+const GITHUB_REPO = 'SableClient/Sable';
+const APK_NAME = `Sable-${version}-android-universal.apk`;
+const APK_URL = `https://github.com/${GITHUB_REPO}/releases/download/${tag}/${APK_NAME}`;
+const isNightly = tag === 'nightly';
+
+// Obtainium fills in the rest from its own defaults on import.
+const additionalSettings = {
+  about: 'An almost stable Matrix client',
+  ...(isNightly && {
+    includePrereleases: true,
+    // The nightly tag name never changes, so the re-uploaded APK's date is the
+    // only usable version, which in turn needs pseudo-versioning.
+    useLatestAssetDateAsReleaseDate: true,
+    releaseDateAsVersion: true,
+    versionDetection: false,
+  }),
+};
+
+const config = {
+  apps: [
+    {
+      id: 'moe.sable.client',
+      url: `https://github.com/${GITHUB_REPO}`,
+      author: 'SableClient',
+      name: 'Sable',
+      installedVersion: null,
+      latestVersion: version,
+      apkUrls: JSON.stringify([[APK_NAME, APK_URL]]),
+      otherAssetUrls: '[]',
+      preferredApkIndex: 0,
+      additionalSettings: JSON.stringify(additionalSettings),
+      lastUpdateCheck: null,
+      pinned: false,
+      categories: ['Communication'],
+      releaseDate: null,
+      changeLog: null,
+      overrideSource: 'GitHub',
+      allowIdChange: false,
+      pendingRepoRenameUrl: null,
+    },
+  ],
+};
+
+writeFileSync(resolve(outputPath), JSON.stringify(config, null, 2) + '\n');
+console.log(`Generated ${outputPath}`);