What needs to be done to describe a GET request?

REST interface, URL, HTTP GET method.

interface ApiService {
    @GET("/api/v1/items") // Description of GET request with path
    suspend fun getItems(): List<Item> // Function to execute request, returning a list of Item
}

Using the Retrofit2 library to create a client and execute requests.

val retrofit = Retrofit.Builder()
    .baseUrl("https://api.example.com/") // Base URL of the API
    .addConverterFactory(GsonConverterFactory.create()) // Converter for parsing JSON
    .build()

val apiService = retrofit.create(ApiService::class.java) // Creating an instance of the service

// Executing the request in a coroutine or another thread
try {
    val items = apiService.getItems()
    // Processing the received data
} catch (e: Exception) {
    // Error handling
}

Depending on the task, request parameters (Query Parameters) or headers (Headers) may be required.

interface ApiService {
    @GET("/api/v1/items")
    suspend fun getItems(
        @Query("category") category: String? = null, // Query parameter "category"
        @Header("Authorization") authHeader: String // Header "Authorization"
    ): List<Item>
}