How can make this network calls run simultaneously using Retrofit and Coroutines

# coroutines

[Kulwinder Singh]

How can make this network calls run simultaneously using Retrofit and Coroutines

Retrofit_calls_simultaneously.kt

[streetsofboston]

lifecycleScope.launch {
            val response1 = async { api.getResponse1() }
            val response2 = async { api.getResponse2() }
            val response3 = async { api.getResponse3() }
            val totalResponses = listOf(response1, response2, response3).awaitAll()
            ... iterate over the totalResponses to compute your final result ... 
        }

[Kulwinder Singh]

but here all responses are diffrent types, so while iterating i also have to check type

[simon.vergauwen]

combine(reponse1.await(), reponse2.await(), reponse3.await()) works as well and that way you don’t lose the type information. Here combine is a simple function (A, B, C) -> D.

[Kulwinder Singh]

please can you share any example of this

[simon.vergauwen]

lifecycleScope.launch {
            val response1: Deferred<Address> = async { api.getResponse1() }
            val response2: Deferred<Name> = async { api.getResponse2() }
            val response3: Deferred<Age> = async { api.getResponse3() }
           val createUser: (Address, Name, Age) -> User = TODO()
val user = createUser(response1.await(), response2.await(), response3.await())
        }

[Kulwinder Singh]

so does it pass result in lambda ?

[simon.vergauwen]

suspend fun <A> Deferred<A>.await(): A

[simon.vergauwen]

So basically what you do here is you start 3 async tasks, and while they’re running in parallel you await them sequentially.

[Kulwinder Singh]

yes, i think this can work best, thank you very much for your help 👍

[simon.vergauwen]

Glad I could help 👍