Support for async interface

[silviucpp]

Hello,

Right now the API provides only methods that blocks the current process until the response is received. Can you add API's that sends the response when is ready to a specified PID ?

Silviu

[puzza007]

It's certainly possible. At the moment it uses https://erlang.org/doc/man/gen_server.html#reply-2 to make synchronous responses. Do you have an existing asynch API in mind?

[silviucpp]

I'm thinking that inside the request options to add:

• async = true| false (default is false to work as it is now)
• reply_to = any pid (default to self())

And when async = true the katipo:req to return {ok, ResponseReference::ref()}

Once the response is available the process indicated in reply_to to receive a message like:

{katipo_resp, ResponseReference, Response} where ResponseReference to be the one you returned in the request and
Response to be the HTTP call response:

#{status := 200,
       headers := RespHeaders,
       cookiejar := CookieJar,
       body := RespBody}

or whatever katipo:req returns normally when using sync calls.

What do you think ?

Silviu

[puzza007]

Cool so basically something like https://github.com/benoitc/hackney#get-a-response-asynchronously 👍

[silviucpp]

@puzza007 I honestly inspired myself from https://github.com/lpgauth/buoy . Difference is that in buoy you get on single message at the end of the response with the response. In hackney you get multiple messages progressively like: when you get the headers, when you get the body and one at the final... This makes most of the use cases complicated because you have to aggregate yourself everything and when the done response comes you know you have the response.

[puzza007]

Cool. I've started a branch with some very early work. I haven't got it running yet.