shihaam/textpipe

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Shihaam Abdul Rahman c35b466de6

working api and app

2026-02-06 00:38:02 +05:00

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Textpipe SMS API Gateway - Implementation Plan

Overview

Build an Android SMS API Gateway with an embedded HTTP server (Ktor), dual SIM support, local message database, and background service.

Architecture

┌─────────────────────────────────────────────────────────────────┐
│                         MainActivity                            │
│                    (Compose UI + Permissions)                   │
└─────────────────────────────────────────────────────────────────┘
                                 │
                                 ▼
┌─────────────────────────────────────────────────────────────────┐
│                      TextpipeService                            │
│              (Foreground Service + Lifecycle)                   │
│  ┌──────────────────────────────────────────────────────────┐  │
│  │                   TextpipeServer (Ktor CIO)              │  │
│  │  ┌─────────────┐  ┌─────────────┐  ┌─────────────────┐  │  │
│  │  │ /api/status │  │/api/sms/send│  │/api/sms/messages│  │  │
│  │  └─────────────┘  └─────────────┘  └─────────────────┘  │  │
│  └──────────────────────────────────────────────────────────┘  │
└─────────────────────────────────────────────────────────────────┘
         │                    │                    │
         ▼                    ▼                    ▼
┌─────────────┐      ┌─────────────┐      ┌─────────────────┐
│ SimManager  │      │  SmsSender  │      │  SmsRepository  │
│ (API Keys)  │      │ (SmsManager)│      │  (Room + Send)  │
└─────────────┘      └─────────────┘      └─────────────────┘
                            │                    │
                            ▼                    ▼
                     ┌─────────────────────────────────┐
                     │        AppDatabase (Room)       │
                     │      sms_messages table         │
                     └─────────────────────────────────┘

Package Structure

sh.sar.textpipe/
├── MainActivity.kt              (modify)
├── TextpipeApplication.kt       (create)
├── data/
│   ├── db/
│   │   ├── AppDatabase.kt
│   │   ├── SmsMessageDao.kt
│   │   └── SmsMessageEntity.kt
│   ├── model/
│   │   └── ApiModels.kt
│   └── repository/
│       └── SmsRepository.kt
├── server/
│   ├── TextpipeServer.kt
│   ├── auth/
│   │   └── ApiKeyAuth.kt
│   └── routes/
│       ├── SmsRoutes.kt
│       └── StatusRoutes.kt
├── service/
│   ├── TextpipeService.kt
│   ├── BootReceiver.kt
│   ├── SmsReceiver.kt
│   └── SmsSender.kt
├── sim/
│   └── SimManager.kt
├── root/
│   └── RootManager.kt
└── ui/
    ├── MainScreen.kt
    └── MainViewModel.kt

API Endpoints

Authentication

API key in header: Authorization: Bearer <key> or X-API-Key: <key>
Each SIM slot has its own unique API key (auto-generated, persistent)
API key determines which SIM sends the message

Endpoints

Method	Path	Auth	Description
GET	`/api/status`	No	Server health, SIM info, uptime
POST	`/api/sms/send`	Yes	Send SMS
GET	`/api/sms/messages`	Yes	List messages (optional `?type=sent\|received`)
GET	`/api/sms/status/{id}`	Yes	Get specific message status

Request/Response Examples

POST /api/sms/send

// Request
{ "to": "+1234567890", "text": "Hello World" }

// Response
{ "id": 1, "status": "pending", "simSlot": 0 }

GET /api/sms/messages

[
  {
    "id": 1,
    "type": "sent",
    "address": "+1234567890",
    "text": "Hello World",
    "simSlot": 0,
    "status": "delivered",
    "timestamp": 1707148800000,
    "deliveryTimestamp": 1707148805000
  }
]

GET /api/status

{
  "running": true,
  "port": 8080,
  "uptime": 3600000,
  "sims": [
    { "slot": 0, "carrier": "Carrier1", "number": "+1...", "hasApiKey": true },
    { "slot": 1, "carrier": "Carrier2", "number": "+1...", "hasApiKey": true }
  ]
}

Dependencies to Add

libs.versions.toml additions

[versions]
ktor = "3.0.3"
room = "2.6.1"
kotlinxSerialization = "1.7.3"
datastorePreferences = "1.1.1"
ksp = "2.0.21-1.0.28"
coroutines = "1.9.0"

[libraries]
ktor-server-core = { group = "io.ktor", name = "ktor-server-core", version.ref = "ktor" }
ktor-server-cio = { group = "io.ktor", name = "ktor-server-cio", version.ref = "ktor" }
ktor-server-content-negotiation = { group = "io.ktor", name = "ktor-server-content-negotiation", version.ref = "ktor" }
ktor-serialization-kotlinx-json = { group = "io.ktor", name = "ktor-serialization-kotlinx-json", version.ref = "ktor" }
ktor-server-status-pages = { group = "io.ktor", name = "ktor-server-status-pages", version.ref = "ktor" }
ktor-server-cors = { group = "io.ktor", name = "ktor-server-cors", version.ref = "ktor" }
room-runtime = { group = "androidx.room", name = "room-runtime", version.ref = "room" }
room-ktx = { group = "androidx.room", name = "room-ktx", version.ref = "room" }
room-compiler = { group = "androidx.room", name = "room-compiler", version.ref = "room" }
kotlinx-serialization-json = { group = "org.jetbrains.kotlinx", name = "kotlinx-serialization-json", version.ref = "kotlinxSerialization" }
datastore-preferences = { group = "androidx.datastore", name = "datastore-preferences", version.ref = "datastorePreferences" }
kotlinx-coroutines-android = { group = "org.jetbrains.kotlinx", name = "kotlinx-coroutines-android", version.ref = "coroutines" }

[plugins]
kotlin-serialization = { id = "org.jetbrains.kotlin.plugin.serialization", version.ref = "kotlin" }
ksp = { id = "com.google.devtools.ksp", version.ref = "ksp" }

Permissions Required

<!-- SMS -->
<uses-permission android:name="android.permission.SEND_SMS" />
<uses-permission android:name="android.permission.RECEIVE_SMS" />
<uses-permission android:name="android.permission.READ_SMS" />

<!-- Phone/SIM -->
<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<uses-permission android:name="android.permission.READ_PHONE_NUMBERS" />

<!-- Network -->
<uses-permission android:name="android.permission.INTERNET" />

<!-- Background Service -->
<uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
<uses-permission android:name="android.permission.FOREGROUND_SERVICE_SPECIAL_USE" />
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<uses-permission android:name="android.permission.WAKE_LOCK" />

<!-- Battery -->
<uses-permission android:name="android.permission.REQUEST_IGNORE_BATTERY_OPTIMIZATIONS" />

<!-- Notifications -->
<uses-permission android:name="android.permission.POST_NOTIFICATIONS" />

Implementation Order

Phase 0: Build Configuration

gradle/libs.versions.toml - Add all new dependencies
build.gradle.kts (root) - Add KSP and serialization plugins
app/build.gradle.kts - Add dependencies and plugins
AndroidManifest.xml - Add permissions, services, receivers

Phase 1: Data Layer

data/model/ApiModels.kt - Request/response data classes
data/db/SmsMessageEntity.kt - Room entity
data/db/SmsMessageDao.kt - Database operations
data/db/AppDatabase.kt - Room database

Phase 2: Core Managers

sim/SimManager.kt - SIM detection, API key management
root/RootManager.kt - Root access and iptables port redirect

Phase 3: SMS Operations

service/SmsSender.kt - Send SMS with delivery tracking
data/repository/SmsRepository.kt - Combine database + sending
service/SmsReceiver.kt - Receive incoming SMS

Phase 4: HTTP Server

server/auth/ApiKeyAuth.kt - API key validation
server/routes/StatusRoutes.kt - Health check endpoint
server/routes/SmsRoutes.kt - SMS API endpoints
server/TextpipeServer.kt - Ktor server configuration

Phase 5: Service Layer

service/TextpipeService.kt - Foreground service
service/BootReceiver.kt - Auto-start on boot
TextpipeApplication.kt - Application class

Phase 6: UI Layer

ui/MainViewModel.kt - UI state management
ui/MainScreen.kt - Compose UI
MainActivity.kt - Update with permissions and new UI

Key Technical Decisions

HTTP Server

Ktor CIO engine (not Netty) - lighter weight for Android
Server runs on configurable port (default 8080)
For ports 80/443: Use iptables NAT redirect via su (don't run JVM as root)

Dual SIM Support

SubscriptionManager.getActiveSubscriptionInfoList() for SIM detection
SmsManager.createForSubscriptionId(subscriptionId) for sending
API key maps to subscription ID, not slot index

SMS Delivery Tracking

PendingIntents for sent confirmation and delivery reports
Update database status: pending → sent → delivered/failed
Multipart SMS via sendMultipartTextMessage()

Background Persistence

Foreground service with persistent notification
FOREGROUND_SERVICE_TYPE_SPECIAL_USE for API 34+
Boot receiver for auto-start

API Key Storage

SharedPreferences (not DataStore) for synchronous reads
Key format: UUID, stored per SIM slot
Generated on first run, persistent across app updates

Files to Create/Modify (22 total)

#	File	Action
1	`gradle/libs.versions.toml`	Modify
2	`build.gradle.kts` (root)	Modify
3	`app/build.gradle.kts`	Modify
4	`app/src/main/AndroidManifest.xml`	Modify
5	`data/model/ApiModels.kt`	Create
6	`data/db/SmsMessageEntity.kt`	Create
7	`data/db/SmsMessageDao.kt`	Create
8	`data/db/AppDatabase.kt`	Create
9	`sim/SimManager.kt`	Create
10	`root/RootManager.kt`	Create
11	`service/SmsSender.kt`	Create
12	`data/repository/SmsRepository.kt`	Create
13	`service/SmsReceiver.kt`	Create
14	`server/auth/ApiKeyAuth.kt`	Create
15	`server/routes/StatusRoutes.kt`	Create
16	`server/routes/SmsRoutes.kt`	Create
17	`server/TextpipeServer.kt`	Create
18	`service/TextpipeService.kt`	Create
19	`service/BootReceiver.kt`	Create
20	`TextpipeApplication.kt`	Create
21	`ui/MainViewModel.kt`	Create
22	`ui/MainScreen.kt`	Create
23	`MainActivity.kt`	Modify

UI Features (Basic for now)

Server status indicator (Running/Stopped)
Port configuration input
Start/Stop toggle button
SIM cards list with:
- Carrier name
- Phone number (if available)
- API key with copy button
Root port redirect toggle (if root available)
Battery optimization exemption button

Out of Scope (Deferred)

WebUI for viewing messages in browser
Rate limiting
IP whitelisting
HTTPS/TLS (beyond port redirect)
Message scheduling
Webhook callbacks

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