Module: Kward::ModelStreamParser

Defined in:
lib/kward/model/stream_parser.rb

Overview

Parses streaming provider responses into Kward assistant messages.

ModelStreamParser is intentionally provider-shape focused and side-effect light: it accumulates assistant text, reasoning summaries, tool calls, and normalized usage from SSE events. Network IO, retries, credentials, and telemetry stay in Client; frontend rendering stays in CLI/RPC event handlers. Keep parser methods deterministic and easy to unit test with raw response bodies.

Class Method Summary collapse

Class Method Details

.anthropic_sse_error(data, request_error_class: nil) ⇒ Object 



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# File 'lib/kward/model/stream_parser.rb', line 157

def anthropic_sse_error(data, request_error_class: nil)
  if request_error_class
    request_error_class.new(provider: "Anthropic", code: 400, body: data)
  else
    data
  end
end

.anthropic_sse_message(state) ⇒ Object 



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# File 'lib/kward/model/stream_parser.rb', line 179

def anthropic_sse_message(state)
  message = { "role" => "assistant", "content" => state[:content] }
  message["reasoning_summary"] = state[:reasoning_summary] unless state[:reasoning_summary].empty?
  message["tool_calls"] = state[:tool_calls] unless state[:tool_calls].empty?
  message["usage"] = state[:usage] if state[:usage]
  message
end

.anthropic_sse_state ⇒ Object 



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# File 'lib/kward/model/stream_parser.rb', line 104

def anthropic_sse_state
  { content: +"", reasoning_summary: +"", blocks: {}, tool_calls: [], usage: nil }
end

.anthropic_tool_call(block_data) ⇒ Object 



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# File 'lib/kward/model/stream_parser.rb', line 165

def anthropic_tool_call(block_data)
  return nil unless block_data.is_a?(Hash) && block_data["type"] == "tool_use"

  name = from_claude_code_tool_name(block_data["name"])
  arguments = block_data["partial_json"].to_s
  arguments = JSON.dump(block_data["input"] || {}) if arguments.empty?
  arguments = "{}" if arguments.empty?
  {
    "id" => block_data["id"] || "call_#{name}",
    "type" => "function",
    "function" => { "name" => name, "arguments" => arguments }
  }
end

.codex_sse_error(event, request_error_class: nil) ⇒ Object 



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# File 'lib/kward/model/stream_parser.rb', line 261

def codex_sse_error(event, request_error_class: nil)
  response = event["response"]
  error = event["error"] || (response["error"] if response.is_a?(Hash)) || {}
  message = if error.is_a?(Hash)
              [error["code"], error["message"]].compact.join(": ")
            else
              error.to_s
            end
  message = event["type"].to_s if message.empty?
  code = error.is_a?(Hash) && error["code"].to_s == "server_error" ? 500 : 400
  if request_error_class
    request_error_class.new(provider: "Codex", code: code, body: "#{event["type"]}: #{message}")
  else
    "#{event["type"]}: #{message}"
  end
end

.codex_sse_message(state) ⇒ Object 



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# File 'lib/kward/model/stream_parser.rb', line 278

def codex_sse_message(state)
  if state[:tool_calls].empty?
    state[:final_output].each do |item|
      tool_call = codex_tool_call(item)
      state[:tool_calls] << tool_call if tool_call
    end
  end

  message = { "role" => "assistant", "content" => state[:content] }
  message["reasoning_summary"] = state[:reasoning_summary] unless state[:reasoning_summary].empty?
  message["tool_calls"] = state[:tool_calls] unless state[:tool_calls].empty?
  message["usage"] = state[:usage] if state[:usage]
  message
end

.codex_sse_state ⇒ Object 



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# File 'lib/kward/model/stream_parser.rb', line 220

def codex_sse_state
  { content: +"", reasoning_summary: +"", tool_calls: [], final_output: [], usage: nil }
end

.codex_tool_call(item) ⇒ Object 



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# File 'lib/kward/model/stream_parser.rb', line 293

def codex_tool_call(item)
  return nil unless item.is_a?(Hash) && ["function_call", "custom_tool_call"].include?(item["type"])

  name = item["name"].to_s
  return nil if name.empty?

  arguments = item["arguments"] || item["input"] || "{}"
  arguments = JSON.dump(arguments) unless arguments.is_a?(String)
  {
    "id" => (item["call_id"] || item["id"] || "call_#{name}"),
    "type" => "function",
    "function" => { "name" => name, "arguments" => arguments }
  }
end

.finalized_streaming_tool_calls(tool_calls) ⇒ Object 



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# File 'lib/kward/model/stream_parser.rb', line 210

def finalized_streaming_tool_calls(tool_calls)
  tool_calls.compact.each_with_index.map do |tool_call, index|
    tool_call["id"] ||= "call_#{index}"
    tool_call["type"] ||= "function"
    tool_call["function"] ||= { "name" => "", "arguments" => "{}" }
    tool_call["function"]["arguments"] = "{}" if tool_call["function"]["arguments"].to_s.empty?
    tool_call
  end
end

.from_claude_code_tool_name(name) ⇒ Object 



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# File 'lib/kward/model/stream_parser.rb', line 187

def from_claude_code_tool_name(name)
  case name.to_s
  when "Read" then "read_file"
  when "Write" then "write_file"
  when "Edit" then "edit_file"
  when "Bash" then "run_shell_command"
  when "WebSearch" then "web_search"
  when "AskUserQuestion" then "ask_user_question"
  else name.to_s
  end
end

.merge_streaming_tool_call(tool_calls, delta) ⇒ Object 



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# File 'lib/kward/model/stream_parser.rb', line 199

def merge_streaming_tool_call(tool_calls, delta)
  index = (delta["index"] || tool_calls.length).to_i
  tool_calls[index] ||= { "id" => nil, "type" => "function", "function" => { "name" => "", "arguments" => "" } }
  current = tool_calls[index]
  current["id"] = delta["id"] if delta["id"]
  current["type"] = delta["type"] if delta["type"]
  function = delta["function"] || {}
  current["function"]["name"] << function["name"].to_s if function["name"]
  current["function"]["arguments"] << function["arguments"].to_s if function["arguments"]
end

.parse_anthropic_sse_stream(response, on_reasoning_delta: nil, on_assistant_delta: nil, cancellation: nil, usage_normalizer: nil, request_error_class: nil) ⇒ Object 



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# File 'lib/kward/model/stream_parser.rb', line 84

def parse_anthropic_sse_stream(response, on_reasoning_delta: nil, on_assistant_delta: nil, cancellation: nil, usage_normalizer: nil, request_error_class: nil)
  state = anthropic_sse_state
  buffer = +""
  response.read_body do |chunk|
    cancellation&.raise_if_cancelled!
    buffer << chunk
    while (index = buffer.index(/\r?\n\r?\n/))
      delimiter = Regexp.last_match[0]
      block = buffer[0...index]
      buffer = buffer[(index + delimiter.length)..] || +""
      process_anthropic_sse_block(block, state, on_reasoning_delta: on_reasoning_delta, on_assistant_delta: on_assistant_delta, usage_normalizer: usage_normalizer, request_error_class: request_error_class)
    end
  end
  cancellation&.raise_if_cancelled!
  process_anthropic_sse_block(buffer, state, on_reasoning_delta: on_reasoning_delta, on_assistant_delta: on_assistant_delta, usage_normalizer: usage_normalizer, request_error_class: request_error_class) unless buffer.empty?
  anthropic_sse_message(state)
rescue JSON::ParserError => e
  raise "Anthropic returned invalid SSE JSON: #{e.message}"
end

.parse_codex_sse(body, on_reasoning_delta: nil, on_assistant_delta: nil, usage_normalizer: nil, request_error_class: nil) ⇒ Object 



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# File 'lib/kward/model/stream_parser.rb', line 48

def parse_codex_sse(body, on_reasoning_delta: nil, on_assistant_delta: nil, usage_normalizer: nil, request_error_class: nil)
  state = codex_sse_state
  body.split(/\r?\n\r?\n/).each do |block|
    process_codex_sse_block(block, state, on_reasoning_delta: on_reasoning_delta, on_assistant_delta: on_assistant_delta, usage_normalizer: usage_normalizer, request_error_class: request_error_class)
  end
  codex_sse_message(state)
rescue JSON::ParserError => e
  raise "Codex OAuth returned invalid SSE JSON: #{e.message}"
end

.parse_codex_sse_stream(response, on_reasoning_delta: nil, on_assistant_delta: nil, cancellation: nil, usage_normalizer: nil, request_error_class: nil) ⇒ Object

Incrementally parses a Codex/Responses SSE HTTP response body.

Deltas are yielded as soon as complete SSE blocks arrive so interactive frontends can render streamed assistant and reasoning text without waiting for the provider to close the response.



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# File 'lib/kward/model/stream_parser.rb', line 63

def parse_codex_sse_stream(response, on_reasoning_delta: nil, on_assistant_delta: nil, cancellation: nil, usage_normalizer: nil, request_error_class: nil)
  state = codex_sse_state
  buffer = +""

  response.read_body do |chunk|
    cancellation&.raise_if_cancelled!
    buffer << chunk
    while (index = buffer.index(/\r?\n\r?\n/))
      delimiter = Regexp.last_match[0]
      block = buffer[0...index]
      buffer = buffer[(index + delimiter.length)..] || +""
      process_codex_sse_block(block, state, on_reasoning_delta: on_reasoning_delta, on_assistant_delta: on_assistant_delta, usage_normalizer: usage_normalizer, request_error_class: request_error_class)
    end
  end
  cancellation&.raise_if_cancelled!
  process_codex_sse_block(buffer, state, on_reasoning_delta: on_reasoning_delta, on_assistant_delta: on_assistant_delta, usage_normalizer: usage_normalizer, request_error_class: request_error_class) unless buffer.empty?
  codex_sse_message(state)
rescue JSON::ParserError => e
  raise "Codex OAuth returned invalid SSE JSON: #{e.message}"
end

.parse_openai_chat_sse(body, on_assistant_delta: nil, usage_normalizer: nil) ⇒ Object 



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# File 'lib/kward/model/stream_parser.rb', line 16

def parse_openai_chat_sse(body, on_assistant_delta: nil, usage_normalizer: nil)
  content = +""
  tool_calls = []
  usage = nil
  body.split(/\r?\n\r?\n/).each do |block|
    data = block.lines.filter_map { |line| line.start_with?("data:") ? line.delete_prefix("data:").strip : nil }.join("\n")
    next if data.empty? || data == "[DONE]"

    event = JSON.parse(data)
    usage ||= usage_normalizer&.call(event["usage"])
    choice = Array(event["choices"]).first || {}
    delta = choice["delta"] || {}
    if delta["content"]
      text = delta["content"].to_s
      content << text
      on_assistant_delta&.call(text)
    end
    Array(delta["tool_calls"]).each do |tool_call|
      merge_streaming_tool_call(tool_calls, tool_call)
    end
    message = choice["message"] || {}
    content << message["content"].to_s if content.empty? && message["content"]
    Array(message["tool_calls"]).each { |tool_call| merge_streaming_tool_call(tool_calls, tool_call) }
  end
  result = { "role" => "assistant", "content" => content }
  result["tool_calls"] = finalized_streaming_tool_calls(tool_calls) unless tool_calls.empty?
  result["usage"] = usage if usage
  result
rescue JSON::ParserError => e
  raise "Copilot returned invalid SSE JSON: #{e.message}"
end

.process_anthropic_sse_block(block, state, on_reasoning_delta: nil, on_assistant_delta: nil, usage_normalizer: nil, request_error_class: nil) ⇒ Object 



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# File 'lib/kward/model/stream_parser.rb', line 108

def process_anthropic_sse_block(block, state, on_reasoning_delta: nil, on_assistant_delta: nil, usage_normalizer: nil, request_error_class: nil)
  event_name = nil
  data = block.lines.filter_map do |line|
    event_name = line.delete_prefix("event:").strip if line.start_with?("event:")
    line.start_with?("data:") ? line.delete_prefix("data:").strip : nil
  end.join("\n")
  return if data.empty? || data == "[DONE]"
  raise anthropic_sse_error(data, request_error_class: request_error_class) if event_name == "error"

  event = JSON.parse(data)
  case event["type"]
  when "message_start"
    state[:usage] ||= usage_normalizer&.call(event.dig("message", "usage"))
  when "content_block_start"
    block_data = event["content_block"] || {}
    state[:blocks][event["index"].to_i] = block_data.merge("partial_json" => "")
    if block_data["type"] == "text"
      text = block_data["text"].to_s
      state[:content] << text
      on_assistant_delta&.call(text) unless text.empty?
    elsif block_data["type"] == "thinking"
      text = block_data["thinking"].to_s
      state[:reasoning_summary] << text
      on_reasoning_delta&.call(text) unless text.empty?
    end
  when "content_block_delta"
    current = state[:blocks][event["index"].to_i] ||= { "partial_json" => "" }
    delta = event["delta"] || {}
    case delta["type"]
    when "text_delta"
      text = delta["text"].to_s
      state[:content] << text
      on_assistant_delta&.call(text)
    when "thinking_delta"
      text = delta["thinking"].to_s
      state[:reasoning_summary] << text
      on_reasoning_delta&.call(text)
    when "input_json_delta"
      current["partial_json"] = current["partial_json"].to_s + delta["partial_json"].to_s
    end
  when "content_block_stop"
    block_data = state[:blocks][event["index"].to_i]
    tool_call = anthropic_tool_call(block_data)
    state[:tool_calls] << tool_call if tool_call
  when "message_delta"
    state[:usage] = usage_normalizer&.call(event["usage"]) || state[:usage]
  end
end

.process_codex_sse_block(block, state, on_reasoning_delta: nil, on_assistant_delta: nil, usage_normalizer: nil, request_error_class: nil) ⇒ Object 



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# File 'lib/kward/model/stream_parser.rb', line 224

def process_codex_sse_block(block, state, on_reasoning_delta: nil, on_assistant_delta: nil, usage_normalizer: nil, request_error_class: nil)
  data = block.lines.filter_map { |line| line.start_with?("data:") ? line.delete_prefix("data:").strip : nil }.join("\n")
  return if data.empty? || data == "[DONE]"

  event = JSON.parse(data)
  case event["type"]
  when "response.output_text.delta"
    delta = event["delta"].to_s
    state[:content] << delta
    on_assistant_delta&.call(delta)
  when "response.reasoning_summary_text.delta"
    delta = event["delta"].to_s
    state[:reasoning_summary] << delta
    on_reasoning_delta&.call(delta)
  when "response.output_item.done"
    item = event["item"]
    state[:final_output] << item if item.is_a?(Hash)
    tool_call = codex_tool_call(item)
    state[:tool_calls] << tool_call if tool_call
  when "response.completed"
    response = event["response"]
    state[:usage] ||= usage_normalizer&.call(response["usage"]) if response.is_a?(Hash)
    state[:usage] ||= usage_normalizer&.call(event["usage"])
    if state[:content].empty? && response.is_a?(Hash) && response["output"].is_a?(Array)
      state[:final_output] = response["output"]
      text = text_from_codex_items(state[:final_output])
      state[:content] << text
      on_assistant_delta&.call(text) unless text.empty?
      if state[:reasoning_summary].empty?
        state[:reasoning_summary] << reasoning_summary_from_codex_items(state[:final_output])
      end
    end
  when "response.failed", "response.incomplete"
    raise codex_sse_error(event, request_error_class: request_error_class)
  end
end

.reasoning_summary_from_codex_items(items) ⇒ Object 



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# File 'lib/kward/model/stream_parser.rb', line 322

def reasoning_summary_from_codex_items(items)
  items.flat_map do |item|
    next [] unless item.is_a?(Hash)

    if item["type"] == "reasoning" && item["summary"].is_a?(Array)
      item["summary"].filter_map { |part| part["text"] if part.is_a?(Hash) }
    else
      []
    end
  end.join
end

.text_from_codex_items(items) ⇒ Object 



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# File 'lib/kward/model/stream_parser.rb', line 308

def text_from_codex_items(items)
  items.flat_map do |item|
    next [] unless item.is_a?(Hash)

    if ["output_text", "text"].include?(item["type"])
      item["text"].to_s
    elsif item["type"] == "message" && item["content"].is_a?(Array)
      item["content"].filter_map { |part| part["text"] if part.is_a?(Hash) && ["output_text", "text"].include?(part["type"]) }
    else
      []
    end
  end.join
end