cursor / app /utils.py
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import asyncio
import base64
import json
import random
import string
import time
import uuid
from functools import wraps
from typing import Union, Callable, Any, AsyncGenerator, Dict
from curl_cffi.requests.exceptions import RequestException
from sse_starlette import EventSourceResponse
from starlette.responses import JSONResponse
from app.errors import CursorWebError
from app.models import ChatCompletionRequest, Usage, ToolCall, Message
async def safe_stream_wrapper(
generator_func, *args, **kwargs
) -> Union[EventSourceResponse, JSONResponse]:
"""
安全的流响应包装器
先执行生成器获取第一个值,如果成功才创建流响应
"""
# 创建生成器实例
generator = generator_func(*args, **kwargs)
# 尝试获取第一个值
first_item = await generator.__anext__()
# 如果成功获取第一个值,创建新的生成器包装原生成器
async def wrapped_generator():
# 先yield第一个值
yield first_item
# 然后yield剩余的值
async for item in generator:
yield item
# 创建流响应
return EventSourceResponse(
wrapped_generator(),
media_type="text/event-stream",
headers={
"Cache-Control": "no-cache",
"Connection": "keep-alive",
"X-Accel-Buffering": "no",
},
)
async def error_wrapper(func: Callable, *args, **kwargs) -> Any:
from .config import MAX_RETRIES
for attempt in range(MAX_RETRIES + 1): # 包含初始尝试,所以是 MAX_RETRIES + 1
try:
return await func(*args, **kwargs)
except (CursorWebError, RequestException) as e:
# 如果已经达到最大重试次数,返回错误响应
if attempt == MAX_RETRIES:
if isinstance(e, CursorWebError):
return JSONResponse(
e.to_openai_error(),
status_code=e.response_status_code
)
elif isinstance(e, RequestException):
return JSONResponse(
{
'error': {
'message': str(e),
"type": "http_error",
"code": "http_error"
}
},
status_code=500
)
if attempt < MAX_RETRIES:
continue
return None
def decode_base64url_safe(data):
"""使用安全的base64url解码"""
# 添加必要的填充
missing_padding = len(data) % 4
if missing_padding:
data += '=' * (4 - missing_padding)
return base64.urlsafe_b64decode(data)
def to_async(sync_func):
@wraps(sync_func)
async def async_wrapper(*args):
loop = asyncio.get_running_loop()
return await loop.run_in_executor(None, sync_func, *args)
return async_wrapper
def generate_random_string(length):
"""
生成一个指定长度的随机字符串,包含大小写字母和数字。
"""
# 定义所有可能的字符:大小写字母和数字
characters = string.ascii_letters + string.digits
# 使用 random.choice 从字符集中随机选择字符,重复 length 次,然后拼接起来
random_string = ''.join(random.choice(characters) for _ in range(length))
return random_string
def normalize_tool_name(name: str) -> str:
"""将工具名统一标准化:将所有下划线替换为连字符"""
return name.replace('_', '-')
def match_tool_name(tool_name: str, available_tools: list[str]) -> str:
"""
匹配工具名称,如果不在列表中则尝试标准化匹配
Args:
tool_name: 需要匹配的工具名
available_tools: 可用的工具名列表
Returns:
匹配到的实际工具名,如果没有匹配返回原名称
"""
# 直接匹配
if tool_name in available_tools:
return tool_name
# 标准化后匹配
normalized_input = normalize_tool_name(tool_name)
for available_tool in available_tools:
if normalize_tool_name(available_tool) == normalized_input:
return available_tool
# 没有匹配,返回原名称
return tool_name
async def non_stream_chat_completion(
request: ChatCompletionRequest,
generator: AsyncGenerator[str, None]
) -> Dict[str, Any]:
"""
非流式响应:接受外部异步生成器,收集所有输出返回完整响应
"""
# 收集所有流式输出
full_content = ""
tool_calls = []
usage = Usage(prompt_tokens=0, completion_tokens=0, total_tokens=0)
async for chunk in generator:
if isinstance(chunk, Usage):
usage = chunk
continue
if isinstance(chunk, ToolCall):
tool_calls.append({
"id": chunk.toolId,
"type": "function",
"function": {
"name": chunk.toolName,
"arguments": chunk.toolInput,
}
})
continue
full_content += chunk
# 构造OpenAI格式的响应
response = {
"id": f"chatcmpl-{uuid.uuid4().hex[:29]}",
"object": "chat.completion",
"created": int(time.time()),
"model": request.model,
"choices": [
{
"index": 0,
"message": {
"role": "assistant",
"content": full_content,
"tool_calls": tool_calls
},
"finish_reason": "stop"
}
],
"usage": {
"prompt_tokens": usage.prompt_tokens,
"completion_tokens": usage.completion_tokens,
"total_tokens": usage.total_tokens
}
}
return response
async def stream_chat_completion(
request: ChatCompletionRequest,
generator: AsyncGenerator[str, None]
) -> AsyncGenerator[Dict[str, Any], None]:
"""
流式响应:接受外部异步生成器,包装成OpenAI SSE格式
"""
chat_id = f"chatcmpl-{uuid.uuid4().hex[:29]}"
created_time = int(time.time())
is_send_init = False
# 发送初始流式响应头
initial_response = {
"id": chat_id,
"object": "chat.completion.chunk",
"created": created_time,
"model": request.model,
"choices": [
{
"index": 0,
"delta": {"role": "assistant", "content": ""},
"finish_reason": None
}
]
}
# 流式发送内容
usage = None
tool_call_idx = 0
async for chunk in generator:
if not is_send_init:
yield {
"data": json.dumps(initial_response, ensure_ascii=False)
}
is_send_init = True
if isinstance(chunk, Usage):
usage = chunk
continue
if isinstance(chunk, ToolCall):
data = {
"id": chat_id,
"object": "chat.completion.chunk",
"created": created_time,
"model": request.model,
"choices": [
{
"index": 0,
"delta": {
"tool_calls": [
{
"index": tool_call_idx,
"id": chunk.toolId,
"type": "function",
"function": {
"name": chunk.toolName,
"arguments": chunk.toolInput,
},
}
]
},
"finish_reason": None,
}
],
}
tool_call_idx += 1
yield {'data': json.dumps(data, ensure_ascii=False)}
continue
chunk_response = {
"id": chat_id,
"object": "chat.completion.chunk",
"created": created_time,
"model": request.model,
"choices": [
{
"index": 0,
"delta": {"content": chunk},
"finish_reason": None
}
]
}
yield {"data": json.dumps(chunk_response, ensure_ascii=False)}
# 发送结束标记
final_response = {
"id": chat_id,
"object": "chat.completion.chunk",
"created": created_time,
"model": request.model,
"choices": [
{
"index": 0,
"delta": {},
"finish_reason": "stop"
}
]
}
yield {"data": json.dumps(final_response, ensure_ascii=False)}
if usage:
usage_data = {"id": chat_id, "object": "chat.completion.chunk",
"created": created_time, "model": request.model,
"choices": [],
"usage": {"prompt_tokens": usage.prompt_tokens,
"completion_tokens": usage.completion_tokens,
"total_tokens": usage.total_tokens, "prompt_tokens_details": {
"cached_tokens": 0,
"text_tokens": 0,
"audio_tokens": 0,
"image_tokens": 0
},
"completion_tokens_details": {
"text_tokens": 0,
"audio_tokens": 0,
"reasoning_tokens": 0
},
"input_tokens": 0,
"output_tokens": 0,
"input_tokens_details": None}
}
yield {
"data": json.dumps(usage_data, ensure_ascii=False)
}
yield {"data": "[DONE]"}
async def empty_retry_wrapper(
cursor_chat_func: Callable,
request: ChatCompletionRequest,
max_retries: int = 3
) -> AsyncGenerator[Union[str, Usage, ToolCall], None]:
"""
空回复重试包装器:检测到空回复时自动重试
Args:
cursor_chat_func: cursor_chat函数
request: 聊天请求
max_retries: 最大重试次数
Yields:
str/Usage/ToolCall: 流式输出
Raises:
CursorWebError: 重试后仍然空回复
"""
for retry_count in range(max_retries + 1):
generator = cursor_chat_func(request)
has_content = False
async for chunk in generator:
if isinstance(chunk, ToolCall):
# 工具调用算有内容
has_content = True
yield chunk
return
elif isinstance(chunk, Usage):
# Usage直接透传
yield chunk
else:
# 文本内容
has_content = True
yield chunk
# 如果有内容,正常返回
if has_content:
return
# 没有内容且还有重试次数,继续重试
if retry_count < max_retries:
continue
# 达到最大重试次数仍然空回复,抛出异常
raise CursorWebError(200, f"空回复重试{max_retries}次后仍然失败")
async def truncation_continue_wrapper(
cursor_chat_func: Callable,
request: ChatCompletionRequest,
max_retries: int = 10
) -> AsyncGenerator[Union[str, Usage, ToolCall], None]:
"""
截断继续包装器:实时流式输出,检测到截断时自动重试
Args:
cursor_chat_func: cursor_chat函数
request: 聊天请求
max_retries: 最大重试次数
Yields:
str/Usage/ToolCall: 流式输出
"""
full_content = "" # 累积的完整内容
total_prompt_tokens = 0
total_completion_tokens = 0
total_tokens = 0
current_usage = None
for retry_count in range(max_retries + 1):
generator = cursor_chat_func(request)
current_content = "" # 当前轮次的内容
is_truncated = False
buffer = "" # 缓冲区,仅在重试时使用
buffer_yielded = False # 标记是否已经处理并输出过缓冲区
async for chunk in generator:
if isinstance(chunk, Usage):
current_usage = chunk
# 累加token统计
total_prompt_tokens += chunk.prompt_tokens
total_completion_tokens += chunk.completion_tokens
total_tokens += chunk.total_tokens
# 检查是否截断
is_truncated = chunk.completion_tokens == 4096
break
elif isinstance(chunk, ToolCall):
# 工具调用直接返回
yield chunk
return
else:
# 文本内容
current_content += chunk
if retry_count == 0:
# 第一次请求,实时输出
yield chunk
else:
# 重试时,使用缓冲区
buffer += chunk
last_10_chars = full_content[-10:] if len(full_content) >= 10 else full_content
if not buffer_yielded:
# 检查缓冲区是否包含last_10_chars
if last_10_chars and last_10_chars in buffer:
# 找到匹配,移除并输出剩余部分
buffer = buffer.replace(last_10_chars, "", 1)
if buffer:
yield buffer
buffer = ""
buffer_yielded = True
elif len(buffer) > 20:
# 缓冲区超过20字符还没匹配,直接输出
yield buffer
buffer = ""
buffer_yielded = True
else:
# 已经处理过缓冲区,直接实时输出
yield chunk
buffer = ""
# 处理流结束后的缓冲区
if retry_count > 0 and buffer:
last_10_chars = full_content[-10:] if len(full_content) >= 10 else full_content
if not buffer_yielded and last_10_chars and last_10_chars in buffer:
buffer = buffer.replace(last_10_chars, "", 1)
if buffer:
yield buffer
# 更新累积内容
full_content += current_content
# 检查是否被截断
if not is_truncated:
# 未被截断,返回最终usage
if current_usage:
yield current_usage
return
# 被截断,构造继续对话
last_10_chars = full_content[-10:] if len(full_content) >= 10 else full_content
continue_prompt = f'''你的回复在"{last_10_chars}"处意外中断。
请直接从该处继续输出,遵循以下规则:
1. 以"{last_10_chars}"开头,紧接新内容
2. 若在代码块中,直接续写代码,禁止重复```标记或语言标识
3. 保持原有的格式、缩进和上下文
错误示例:截断于"document."
❌ ```javascript\nlet a=1;\ndocument.createElement...
正确示例:
✅ document.createElement...
立即继续,不要解释或重新开始。'''
# 重新构造上下文
new_messages = request.messages.copy()
new_messages.append(Message(role="assistant", content=full_content, tool_calls=None, tool_call_id=None))
new_messages.append(Message(role="user", content=continue_prompt, tool_calls=None, tool_call_id=None))
request = ChatCompletionRequest(
messages=new_messages,
stream=request.stream,
model=request.model,
tools=request.tools
)
# 达到最大重试次数,返回最终usage
if current_usage:
yield current_usage