How to make async requests using HTTPoison?

I would use Task.start - and then log the error from there should it fail..

Interesting idea, but I am a little bit interested in the result, i.e., as I explained I would like to know if the request failed so I can log it.

Furthermore using Task means I wouldn’t be able to take advantage of the hackney pools HTTPoison uses, so I would have to create a Task (process) for each request instead of taking advantage of the pools already in place, which would result in far less efficient alternative.

Spawn a new process with a receive block and point your stream_to at that instead of self.

use receive to receive the messages… remember to drop those you don’t want to see…

@sanswork
@NobbZ
So there is no way to do this asynchronously using HTTPoison?
What is the async documentation for then? How would one even use it?

I swear I am getting more confused as time goes by.

What we just described is asyc using httpoison.

Of course it is.

1. send the request
2. do whatever you want
3. receive the payload

Thats async for me.

If you do not want to do this in the process that deals with the other stuff, you have to offload it into another process.

Unlike in most languages in Elixir or Erlang it’s trivial for a function to be made asynchronous using processes (possibly using an abstraction such as Task). Because of this we don’t need libraries to implement async versions of the functions they offer- and often we would prefer them not to as one size does not fit all here.

Task.start(fn ->
  case HTTPoison.get("httpbin.org/get", [], hackney: [pool: :first_pool]) do
     ...
     _ -> Logger.whatever(something, request_id, user_id, etc..)
  end
end)

eg you can easily log any errors. (obviously use start/3 for “real” DRY code..)

You can use the pools..

But not sure I understand all the requirements..

The reason I mention why this is confusing is because receive is actually blocking. According to the documentation:

If there is no message in the mailbox matching any of the patterns, the current process will wait until a matching message arrives

I don’t want my process to wait for anything. I want it to go around doing it’s business and if it receives something, to act accordingly. I don’t want to block a process waiting for a response. In reality this would be a perfect case of fire and forget but since I need to know if something failed it is not 100% fire and forget.

So I hope you understand my confusion when you people tell me to use receive, which according to my understanding, actually blocks the process until it receives something.

I guess under this assumption Task.start would make more sense, since I could block the Task instead.

Not sure I agree with the philosophy, but the insight is surely appreciated! It helps me put into context the responses I have been getting thus far!