can I use callbackFlow even though I have not a callBackListener-CodePudding

I'm using GraphQL to fetch the data from the server. The SDK is not suspendable, and I'm trying to use Clean Architecture. So I came up to return a Flow in my repository to allow the UseCases to fetch the server's response. So I have this code in my repository:

override fun singUp(model: SignUpModel): Flow<ResponseModel<SignUpServerResponse>> = callbackFlow {
            ...
          
            client.mutateGraph(signUpQuery)
                .enqueue(object : GraphCallResultCallback<Storefront.Mutation> {
                    override fun invoke(result: GraphCallResult<Storefront.Mutation>) {

                        if (result is GraphCallResult.Success) 
                            trySendBlocking(...).also { close() }
                        else 
                            trySendBlocking(...).also { close() }
                    }
                })
            awaitClose {}
        }

my questions are:

1- Do I need to call the close after each event? Obviously, I don't need the flow to be alive after I fetch the response from the server.

2- I removed awaitClose {}, and I got the error that this field is required and should be used to detach the CallBackListener, but in this case, I don't have one. Is it okay if I'm putting an empty awaitClose {} at the end?

3- I know the flow uses Channels in the background. I also implemented it by channels, is there any advantages ( performance, security, etc.) that I have to using CallBackFlow?

CodePudding user response：

You don't need to use callbackFlow here like mentioned in the comments. If you want to use singUp() method with coroutines you need to convert it to a suspend function. To convert a function, that has callbacks, to a suspend function suspendCoroutine and suspendCancellableCoroutine builders can be used. Example:

suspend fun singUp(model: SignUpModel): ResponseModel<SignUpServerResponse> = suspendCoroutine { continuation ->
        ...
      
        client.mutateGraph(signUpQuery)
            .enqueue(object : GraphCallResultCallback<Storefront.Mutation> {
                override fun invoke(result: GraphCallResult<Storefront.Mutation>) {

                    if (result is GraphCallResult.Success) 
                        continuation.resume(...) // resumes an execution of a coroutine, in which the `singUp` method was called
                    else 
                        continuation.resume(...)
                }
            })
}