https://kotlinlang.org logo
Join Slack
Powered by
If you had Retrofit setup (non suspending) because...
# squarelibraries
c
If you had Retrofit setup (non suspending) because you have a bunch of places in your code where you already use this... BUT you want your new code to use coroutines, what would you do? I feel like maybe I'd create a new duplicate ApiService and add the suspend modifier and get rid of the Call<> return wrapper type. But keeping two api services in sync seems silly. Am I missing something here for how to use my retrofit apiService in the traditional way + coroutine way?
k
How do you consume the 
Call
objects returned from Retrofit?
c
I guess I don't really consume them at all (if im understanding your question correctly). At most I'm basically just doing call?.request()
k
You don’t 
Call.execute
anywhere?
or 
Call.enqueue
?
c
enqueue! Sorry 🤦
k
All good.
Are you certain you want to make the function on the service suspending? You could have a gradual transition by writing an extension on 
Call
called 
executeSuspending
Copy code
suspend fun <T> Call<T>.executeSuspending(): Response<T> = suspendCancellableCoroutine { cont ->
  enqueue(object : Callback {
    override fun onResponse(call: Call<T>, response: Response<T>) = cont.resume(response)
    override fun onFailure(call: Call<T>, t: Throwable) = cont.resumeWithException(t)
  }

  cont.invokeOnCancellation { this@executeSuspending.cancel() }
}
This is super crude as I drafted it in Slack, but that’s what I’d do.
Then, once all of your code a layer above your network services uses coroutines you can drop this and use retrofit suspending natively
c
Are you certain you want to make the function on the service suspending?
I guess not, I'm just used to the "modern" way of calling apiService in my newer projects, but I went back to this codebase and theres no way i can upgrade all of the old stuff. An extension on Call sounds pretty neat actually. idky i didn't think of that.
k
Godspeed!
c
1 last thing with this. i guess i want to use suspend from retrofit because i know it handles all of the dispatchers setup (i.e. calling it is main safe). I guess in this case, I wouldn't get the main safety and I'd still need to switch dispatchers myself?
k
Call.enqueue
internally dispatches call events to a threadpool managed by OkHttp (I’m 99% sure of this, but not certain)
So nothing to worry about with thread safety
Copy code
/**
   * Asynchronously send the request and notify {@code callback} of its response or if an error
   * occurred talking to the server, creating the request, or processing the response.
   */
  void enqueue(Callback<T> callback);
c
ah true. forgot that callsbacks are already thread safe.
k
e
Dunno why it isnt mentioned but Retrofit itself includes that extension. Its called 
await()
k
Oh nice, I had no idea
c
Wait, what? So I don't need the custom executeSuspending() function by Kevin above? theres some built in await function? im on mobile. but will try that in a bit!
k
12 Views
Open in Slack
PreviousNext
Powered by