Network Layer

This chapter explains the network layer implementation in the MediLink app, covering the API service, HTTP client setup, and request handling.

API Service Implementation

class AuthService {
    private val client = HttpClient(Android) {
        install(ContentNegotiation) {
            json(Json {
                ignoreUnknownKeys = true
                isLenient = true
            })
        }
    }

    private val baseUrl = "https://bd16-150-107-16-195.ngrok-free.app/v1"

    suspend fun signup(request: SignupRequest): ApiResponse<User> {
        return client.post("$baseUrl/auth/signup") {
            contentType(ContentType.Application.Json)
            setBody(request)
        }.body()
    }

    suspend fun login(request: LoginRequest): ApiResponse<User> {
        return client.post("$baseUrl/auth/login") {
            contentType(ContentType.Application.Json)
            setBody(request)
        }.body()
    }

    companion object {
        fun create(): AuthService {
            return AuthService()
        }
    }
}

HTTP Client Configuration

1. Ktor Client Setup

HttpClient(Android) {
    install(ContentNegotiation) {
        json(Json {
            ignoreUnknownKeys = true
            isLenient = true
        })
    }
}

The Ktor client configuration:

• Uses Android engine for HTTP requests
• Installs content negotiation for JSON handling
• Configures JSON serialization options

2. Request Configuration

client.post("$baseUrl/auth/signup") {
    contentType(ContentType.Application.Json)
    setBody(request)
}

Request configuration includes:

• Setting content type
• Adding request body
• Configuring headers
• Handling response

Best Practices

1. API Organization

   • Group related endpoints
   • Use clear naming conventions
   • Document API contracts
   • Handle versioning

2. Error Handling

   • Implement proper error responses
   • Handle network errors
   • Provide meaningful error messages
   • Log errors for debugging

3. Security

   • Use HTTPS
   • Implement proper authentication
   • Handle sensitive data
   • Validate responses

4. Performance

   • Use connection pooling
   • Implement caching
   • Handle timeouts
   • Optimize payload size

Next Steps

1. Learn about Data Models
2. Study Authentication
3. Implement Error Handling

Tip: Use Postman or similar tools to test API endpoints before implementation.

Note: Always handle network errors gracefully and provide offline support when possible.