net/http's `read_body` is all you need to read streaming responses from the ChatGPT API. No need for a gem dependency

chat_gpt_streaming_example.rb

require_relative "../config/environment"

uri = URI("https://api.openai.com/v1/chat/completions")
req = Net::HTTP::Post.new(uri)
req["Content-Type"] = "application/json"
req["Authorization"] = "Bearer #{ENV["OPEN_AI_API_KEY"]}"
req.body = JSON.dump({
  model: "gpt-4",
  max_tokens: 80,
  messages: [{role: "user", content: "What's the best way to learn Ruby?"}],
  stream: true
})

Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) do |http|
  http.request(req) do |res|
    if Net::HTTPSuccess === res
      res.read_body do |chunk|
        segments = chunk.split("data: ").map(&:strip).reject { |s| s.empty? || s == "[DONE]" }
        segments.each do |segment|
          payload = JSON.parse(segment).dig("choices", 0, "delta")
          print payload["content"]
        end
      rescue
        puts "Failed while reading:\n\n#{chunk}"
      end
    else
      puts "Failed with #{res.code}"
      puts res.body
    end
  end
end