Defer is described by graphql

[fasibio]

Hi there was an issue years before:
Topic: defer

Now it looks like it's described by graphql core https://graphql.org/blog/2020-12-08-improving-latency-with-defer-and-stream-directives/

So perhaps it's time to think about, how to support it.
What do you think?

[fasibio]

I´am now more deep insinde defer... so perhaps I can try a Implementation.

Theoretical steps needed for this:

• check if header "accept" included "multipart/mixed; deferSpec=20220824" (20220824=is current version)
• find out, which queries has a defer fragment

{ 
   foo{
   fast
     ...defer{
      slow
    } 
  }
}

• find out if slow this goes to a resolver func.
• query fast resolver and slow resolver at an own goroutine
• send body stream of fast and flush to client sorround with:

\r\n--graphql\r\ncontent-type: application/json\r\n\r\n
{{fast json}}

if the answer from slow resulted send to bodystream with:

\r\n--graphql\r\ncontent-type: application/json\r\n\r\n
{{slow json}}
\r\n--graphql--\r\n

clsoe connection

(if there is more than one defer)
send for each

\r\n--graphql\r\ncontent-type: application/json\r\n\r\n
{{json}}

and by last

\r\n--graphql\r\ncontent-type: application/json\r\n\r\n
{{slow json}}
\r\n--graphql--\r\n

(see the close -- after graphql)

so the most difficulte stuff will be:
find out which query is defer and is a resolver behind.
flush data schould not be the problem...

what do you think. i forgot something ? Each Feedback help

[fasibio]

find this PR: https://github.com/99designs/gqlgen/pull/2624/files but there is the --graphql stuff miss what is part of spec...