Files
webtest-agent/llm.py
T

132 lines
4.5 KiB
Python

#!/usr/bin/env python3
"""LLM 客户端(OpenAI 兼容接口)
支持按模型配置调用(base_url / api_key / model / temperature / timeout),
支持多模态消息(content 为 [{type:text},{type:image_url}] 列表,用于视觉模型分析截图)。
"""
import json
import re
import urllib.request
import urllib.error
from config import LLM_BASE_URL, LLM_API_KEY, LLM_MODEL, LLM_TEMPERATURE, LLM_TIMEOUT
class LLMError(Exception):
pass
def _cfg(cfg):
"""补齐默认值,返回完整配置 dict"""
base = {
'base_url': LLM_BASE_URL,
'api_key': LLM_API_KEY,
'model': LLM_MODEL,
'temperature': LLM_TEMPERATURE,
'timeout': LLM_TIMEOUT,
'vision': False,
}
if cfg:
base.update({k: v for k, v in cfg.items() if v is not None})
return base
def _extract_json(text):
"""从 LLM 输出中提取 JSON(容忍 markdown 代码块等包裹)"""
if not text:
return None
text = text.strip()
# 去掉 markdown 代码块
fence = re.search(r'```(?:json)?\s*(.*?)```', text, re.S)
if fence:
text = fence.group(1).strip()
try:
return json.loads(text)
except json.JSONDecodeError:
pass
# 尝试截取第一个 { 到最后一个 }
s, e = text.find('{'), text.rfind('}')
if s != -1 and e > s:
try:
return json.loads(text[s:e + 1])
except json.JSONDecodeError:
return None
return None
def chat(messages, cfg=None, temperature=None, max_tokens=None, timeout=None):
"""调用 OpenAI 兼容 chat/completions,返回 content 字符串
messages 中的 content 可以是字符串,也可以是多模态列表:
[{"type":"text","text":"..."},
{"type":"image_url","image_url":{"url":"data:image/png;base64,..."}}]
"""
c = _cfg(cfg)
url = f"{c['base_url'].rstrip('/')}/chat/completions"
body = {
'model': c['model'],
'messages': messages,
'temperature': temperature if temperature is not None else c['temperature'],
}
if max_tokens:
body['max_tokens'] = max_tokens
req = urllib.request.Request(
url,
data=json.dumps(body).encode('utf-8'),
headers={
'Content-Type': 'application/json',
'Authorization': f'Bearer {c["api_key"]}',
},
method='POST',
)
try:
with urllib.request.urlopen(req, timeout=timeout or c['timeout']) as resp:
data = json.loads(resp.read().decode('utf-8'))
except urllib.error.HTTPError as e:
detail = e.read().decode('utf-8', 'ignore')[:300]
raise LLMError(f'LLM HTTP {e.code}: {detail}')
except Exception as e:
raise LLMError(f'LLM 调用失败: {e}')
try:
msg = data['choices'][0]['message']
content = msg.get('content') or ''
if not content.strip():
# thinking 模型(如 qwen3/deepseek-r1 系):最终答案可能为空,
# 思考过程放在 reasoning_content 里(常包含最终 JSON),用它兜底
reasoning = msg.get('reasoning_content') or ''
if reasoning.strip():
return reasoning
return content
except (KeyError, IndexError, TypeError):
raise LLMError(f'LLM 响应异常: {str(data)[:300]}')
def _trim_content(text, limit=300):
"""截断过长的模型输出(避免超长思考内容反复进入上下文)"""
text = (text or '').strip()
return text if len(text) <= limit else text[:limit] + '...(已截断)'
def chat_json(messages, cfg=None, temperature=None, max_tokens=None, retries=2):
"""调用 LLM 并强制解析 JSON,失败重试"""
last_err = None
last_content = ''
for i in range(retries + 1):
try:
last_content = chat(messages, cfg=cfg, temperature=temperature,
max_tokens=max_tokens)
obj = _extract_json(last_content)
if obj is not None:
return obj
last_err = f'无法从输出解析 JSON: {last_content[:200]}'
except LLMError as e:
last_err = str(e)
if i < retries:
messages = messages + [
{'role': 'assistant', 'content': _trim_content(last_content)},
{'role': 'user',
'content': f'刚才的输出不是合法 JSON,请只输出严格的 JSON 对象,不要输出思考过程和代码块。错误: {last_err}'},
]
raise LLMError(f'LLM JSON 解析失败: {last_err}')