discourse-ai/lib/completions/json_streaming_tracker.rb

72 lines
2.1 KiB
Ruby

# frozen_string_literal: true
module DiscourseAi
module Completions
class JsonStreamingTracker
attr_reader :current_key, :current_value, :stream_consumer
def initialize(stream_consumer)
@stream_consumer = stream_consumer
@current_key = nil
@current_value = nil
@parser = DiscourseAi::Completions::JsonStreamingParser.new
@parser.key do |k|
@current_key = k
@current_value = nil
end
@parser.value do |v|
if @current_key
stream_consumer.notify_progress(@current_key, v)
@current_key = nil
end
end
end
def broken?
@broken
end
def <<(raw_json)
# llm could send broken json
# in that case just deal with it later
# don't stream
return if @broken
begin
@parser << raw_json
rescue DiscourseAi::Completions::ParserError
# Note: We're parsing JSON content that was itself embedded as a string inside another JSON object.
# During the outer JSON.parse, any escaped control characters (like "\\n") are unescaped to real characters ("\n"),
# which corrupts the inner JSON structure when passed to the parser here.
# To handle this, we retry parsing with the string JSON-escaped again (`.dump[1..-2]`) if the first attempt fails.
try_escape_and_parse(raw_json)
return if @broken
end
if @parser.state == :start_string && @current_key
# this is is worth notifying
stream_consumer.notify_progress(@current_key, @parser.buf)
end
@current_key = nil if @parser.state == :end_value
end
private
def try_escape_and_parse(raw_json)
if raw_json.blank? || !raw_json.is_a?(String)
@broken = true
return
end
# Escape the string as JSON and remove surrounding quotes
escaped_json = raw_json.dump[1..-2]
@parser << escaped_json
rescue DiscourseAi::Completions::ParserError
@broken = true
end
end
end
end