/graphql-ruby-urql-stream-example

Primary LanguageRuby

This is a copy of urql's stream example, with the server ported to Sinatra (server/server.rb) and Rails stream_server/

Install dependencies:

yarn install

To start the javascript server:

yarn run start

Or, to start the Sinatra server:

yarn run startruby

Or, to start the Rails server:

cd stream_server
rails server
# Run the JS client separately as described below

Alternatively, start the client with yarn run vite, then start the JS server with node server/index.js or the Ruby server with ruby server/server.rb.

Caveats

There are some differences between the Ruby server's behavior and the JS server.

  • Most notably, the JS server runs multiple "setTimeout" waits at the same time, so secondVerse arrives in the middle of the stream of letters. Ruby, on the other hand, runs one sleep at a time, so letters must pause while secondVerse is sleeping. This could probably be improved by use GraphQL::Dataloader, nonblocking: true, and re-working those fields to use Dataloader sources.

  • Where the alphabet field pauses is slightly different. The JS server uses an iterator-type pattern and pauses while enumerating the alphabet. Ruby, on the other hand, pauses before the char field.

    In my opinion, this is the right approach to @stream in a Ruby/Rails context. Consider a list of items fetched from ActiveRecord: the whole list is returned at once, after a pause (waiting for the SQL query to return). At that point, you'd want to return the results for each item separately. That is, if each item has many selections on it, you'd want to run those "sub-queries" independently.

    (You could get a different behavior by using @defer on the list. This exclude the list from the initial response, sending the whole selection in one patch later.)

    Maybe I'm wrong -- is there an advantage in a Ruby/Rails context to supporting pauses between list items? If so, I bet the use of .each in lib/graphql/execution/interpreter/runtime.rb could be expanded to properly support Ruby enumerators.

  • Weirdly, Sinatra doesn't work right with this example when you set Transfer-Encoding: chunked in Ruby -- can't figure out why.