Python urllib调用巴西空军气象API报错问题求助

我开发了一个调用巴西空军免费METAR气象API的Python程序，前3小时运行正常，之后持续报错无法更新气象信息。

相关代码片段 #

try:
    # caso o resultado anterior não gere dados, sera feita nova conexão
    print(self.horapesquisa)
    objurl = urllib.request.urlopen(f'http://redemet.decea.gov.br//api/consulta_automatica/index.php?local={self.sigla_localidade}&msg=metar&data_ini={self.horapesquisa}&data_fim={self.horapesquisa}')
    if objurl.getcode() == 200:
        self.dados = objurl.read()
        self.dados = str(self.dados)

        inicio = self.dados.find('METAR')
        fim = self.dados.find('=')
        self.dados = self.dados[inicio:fim+1]
except:
    # 原代码未处理异常

报错信息 #

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Users\claud\AppData\Local\Programs\Python\Python310\lib\tkinter\__init__.py", line 1921, in __call__
    return self.func(*args)
  File "C:\Users\claud\AppData\Local\Programs\Python\Python310\lib\tkinter\__init__.py", line 839, in callit
    func(*args)
  File "c:\Users\claud\OneDrive\Documentos\meuusprojetos\METAR\main.py", line 30, in infa
    met = modulos.Metar(localidade,verificador_atraso)
  File "c:\Users\claud\OneDrive\Documentos\meuusprojetos\METAR\modulos\modulos.py", line 41, in __init__
    objurl = urllib.request.urlopen(f'http://redemet.decea.gov.br//api/consulta_automatica/index.php?local={self.sigla_localidade}&msg=metar&data_ini={self.horapesquisa}&data_fim={self.horapesquisa}')
  File "C:\Users\claud\AppData\Local\Programs\Python\Python310\lib\urllib\request.py", line 216, in urlopen
    return opener.open(url, data, timeout)
  File "C:\Users\claud\AppData\Local\Programs\Python\Python310\lib\urllib\request.py", line 519, in open
    response = self._open(req, data)
  File "C:\Users\claud\AppData\Local\Programs\Python\Python310\lib\urllib\request.py", line 536, in _open
    result = self._call_chain(self.handle_open, protocol, protocol +
  File "C:\Users\claud\AppData\Local\Programs\Python\Python310\lib\urllib\request.py", line 496, in _call_chain
    result = func(*args)
  File "C:\Users\claud\AppData\Local\Programs\Python\Python310\lib\urllib\request.py", line 1377, in http_open
    return self.do_open(http.client.HTTPConnection, req)
  File "C:\Users\claud\AppData\Local\Programs\Python\Python310\lib\urllib\request.py", line 1351, in do_open
    raise URLError(err)
urllib.error.URLError: <urlopen error [Errno 11001] getaddrinfo failed>

错误原因分析 #

[Errno 11001] getaddrinfo failed 表示DNS解析失败，无法将域名redemet.decea.gov.br转换为对应IP地址。可能的诱因包括：

• 程序长期运行导致本地DNS缓存失效或网络临时中断
• API服务器DNS记录临时变更
• 网络提供商限制该域名解析
• 请求频率过高触发服务器限制（间接导致DNS层面的阻断）

具体修复步骤 #

1. 修正URL格式问题
   原URL使用了HTML实体&作为参数分隔符，应直接替换为&；同时路径中的//api改为/api避免解析异常：

   # 修正后的URL
   url = f'http://redemet.decea.gov.br/api/consulta_automatica/index.php?local={self.sigla_localidade}&msg=metar&data_ini={self.horapesquisa}&data_fim={self.horapesquisa}'
   objurl = urllib.request.urlopen(url)
   

2. 添加异常处理与重试机制
   原代码空except块无法定位问题，新增DNS失败重试逻辑并设置超时：

   import time
   from urllib.error import URLError
   
   max_retries = 3
   retry_delay = 5  # 重试间隔5秒
   success = False
   
   for attempt in range(max_retries):
       try:
           print(self.horapesquisa)
           url = f'http://redemet.decea.gov.br/api/consulta_automatica/index.php?local={self.sigla_localidade}&msg=metar&data_ini={self.horapesquisa}&data_fim={self.horapesquisa}'
           # 设置10秒超时，避免阻塞
           objurl = urllib.request.urlopen(url, timeout=10)
           if objurl.getcode() == 200:
               # 直接解码为字符串，避免bytes转str的转义问题
               self.dados = objurl.read().decode('utf-8')
               inicio = self.dados.find('METAR')
               fim = self.dados.find('=')
               if inicio != -1 and fim != -1:
                   self.dados = self.dados[inicio:fim+1]
                   success = True
                   break
               else:
                   print("返回数据格式异常，未找到METAR或=标记")
       except URLError as e:
           print(f"请求失败（第{attempt+1}次重试）：{str(e)}")
           time.sleep(retry_delay)
       except Exception as e:
           print(f"未知错误：{str(e)}")
           break
   
   if not success:
       print("多次重试后仍无法获取数据")
   

3. 优化数据解析逻辑
   原代码直接将bytes转为字符串易出现编码问题，改用decode('utf-8')解码；同时增加格式校验，避免无效数据进入后续流程。

4. 排查网络与DNS设置

   • 手动用ping redemet.decea.gov.br测试域名解析是否正常
   • 若本地DNS不稳定，可更换公共DNS（如8.8.8.8或1.1.1.1）

内容的提问来源于stack exchange，提问作者Cláudio Aguiar