使用lxml etree解析函数时出现IOError

Question

我有一个逻辑是这样的：

for root, dirs, files in os.walk(os.getcwd()):
    if "info.xml" in files:
        root = lxml.etree.parse("%s/info.xml" % root)
        tag = root.xpath("/info/tagname")[0].text

当我尝试解析一个路径很深的 info.xml 文件时，遇到了错误信息：

    Traceback (most recent call last):
  File "/home/work/mergefile.py", line 365, in <module>
  File "/home/work/mergefile.py", line 344, in merge_ejb_files
  File "/home/work/mergefile.py", line 63, in __init__
  File "/home/work/mergefile.py", line 78, in _parse_info2doc
  File "lxml.etree.pyx", line 2698, in lxml.etree.parse (src/lxml/lxml.etree.c:49590)
  File "parser.pxi", line 1491, in lxml.etree._parseDocument (src/lxml/lxml.etree.c:71205)
  File "parser.pxi", line 1520, in lxml.etree._parseDocumentFromURL (src/lxml/lxml.etree.c:71488)
  File "parser.pxi", line 1420, in lxml.etree._parseDocFromFile (src/lxml/lxml.etree.c:70583)
  File "parser.pxi", line 975, in lxml.etree._BaseParser._parseDocFromFile (src/lxml/lxml.etree.c:67736)
  File "parser.pxi", line 539, in lxml.etree._ParserContext._handleParseResultDoc (src/lxml/lxml.etree.c:63820)
  File "parser.pxi", line 625, in lxml.etree._handleParseResult (src/lxml/lxml.etree.c:64741)
  File "parser.pxi", line 563, in lxml.etree._raiseParseError (src/lxml/lxml.etree.c:64056)
IOError: Error reading file '/home/work/ci/case/dc_daily/dc/213577/223922/223958/792536/info.xml': failed to load external entity "/home/work/ci/case/dc_daily/dc/213577/223922/223958/792536/info.xml"

但是这个文件 "/home/work/ci/case/dc_daily/dc/213577/223922/223958/792536/info.xml" 是存在的，我在 ipython IDE 中可以用 lxml 成功解析它。

你知道问题出在哪里吗？如果你知道，请帮帮我！谢谢！

Answer 1

这是我的解决方案，跟我上面说的一样。我是先打开文件进行读取，然后马上关闭它们，这样就不会超过1024个文件的限制。

import lxml.etree as etree
for root,dirs,files in os.walk(os.getcwd()):
    if "info.xml" in files:
        with open('%s/info.xml'%root) as processfile: #use 'rb' if necessary
            xml = etree.parse(processfile)
            tag = root.xpath("/info/tagname")[0].text