6
我一直試圖在google應用程序引擎中使用html5lib和python 2.7上的lxml。但是，當我運行下面的代碼時，它給了我一個錯誤，說「NameError：全局名稱'etree'未定義」。是不是可以在谷歌應用程序引擎上使用lxml.etree？或者我錯過了什麼？Google App Engine上的Python 2.7無法使用lxml.etree
的app.yaml
application: testsite
version: 1
runtime: python27
api_version: 1
threadsafe: false
handlers:
- url: /.*
script: index.py
libraries:
- name: lxml
version: "2.3" # I thought this would allow me to use lxml.etree
index.py
from testhandler import TestHandler
application = webapp.WSGIApplication([('/', TestHandler)], debug=True)
testhandler.py
import urllib2
import html5lib
from html5lib import treebuilders
try:
from lxml import etree
print("running with lxml.etree")
except ImportError:
try:
# Python 2.5
import xml.etree.cElementTree as etree
print("running with cElementTree on Python 2.5+")
except ImportError:
try:
# Python 2.5
import xml.etree.ElementTree as etree
print("running with ElementTree on Python 2.5+")
except ImportError:
try:
# normal cElementTree install
import cElementTree as etree
print("running with cElementTree")
except ImportError:
try:
# normal ElementTree install
import elementtree.ElementTree as etree
print("running with ElementTree")
except ImportError:
print("Failed to import ElementTree from any known place")
from google.appengine.ext import webapp
class TestHandler(webapp.RequestHandler):
def get(self):
f = urllib2.urlopen("http://www.yahoo.com/").read()
doc = html5lib.parse(f, treebuilder='lxml')
elems = doc.xpath("//*[local-name() = 'a']")
self.response.out.write(len(elems))
錯誤
running with cElementTree on Python 2.5+
Status: 500 Internal Server Error
Content-Type: text/html; charset=utf-8
Cache-Control: no-cache
Expires: Fri, 01 Jan 1990 00:00:00 GMT
Content-Length: 769
<pre>Traceback (most recent call last):
File "/usr/local/bin/google_appengine/google/appengine/ext/webapp/_webapp25.py", line 701, in __call__
handler.get(*groups)
File "/home/test/testhandler.py", line 38, in get
parser = html5lib.HTMLParser(tree= treebuilders.getTreeBuilder('lxml'))
File "/home/test/html5lib/html5parser.py", line 68, in __init__
self.tree = tree(namespaceHTMLElements)
File "/home/test/html5lib/treebuilders/etree_lxml.py", line 176, in __init__
builder = etree_builders.getETreeModule(etree, fullTree=fullTree)
NameError: global name 'etree' is not defined
</pre>
ADD
那麼，我嘗試了幾種方法來創建一個doc對象，但沒有運氣。其中一種方法，我試圖導入from lxml.html import document_fromstring，這給了我這個錯誤。
Traceback (most recent call last):
File "/usr/local/bin/google_appengine/google/appengine/tools/dev_appserver.py", line 4143, in _HandleRequest
self._Dispatch(dispatcher, self.rfile, outfile, env_dict)
File "/usr/local/bin/google_appengine/google/appengine/tools/dev_appserver.py", line 4049, in _Dispatch
base_env_dict=env_dict)
File "/usr/local/bin/google_appengine/google/appengine/tools/dev_appserver.py", line 616, in Dispatch
base_env_dict=base_env_dict)
File "/usr/local/bin/google_appengine/google/appengine/tools/dev_appserver.py", line 3120, in Dispatch
self._module_dict)
File "/usr/local/bin/google_appengine/google/appengine/tools/dev_appserver.py", line 3024, in ExecuteCGI
reset_modules = exec_script(handler_path, cgi_path, hook)
File "/usr/local/bin/google_appengine/google/appengine/tools/dev_appserver.py", line 2887, in ExecuteOrImportScript
exec module_code in script_module.__dict__
File "/home/yoo/eclipse_workspace/website_checker/src/index.py", line 5, in <module>
from handlers.updatecheck import UpdateCheckHandler
File "/usr/local/bin/google_appengine/google/appengine/tools/dev_appserver.py", line 1538, in Decorate
return func(self, *args, **kwargs)
File "/usr/local/bin/google_appengine/google/appengine/tools/dev_appserver.py", line 2503, in load_module
return self.FindAndLoadModule(submodule, fullname, search_path)
File "/usr/local/bin/google_appengine/google/appengine/tools/dev_appserver.py", line 1538, in Decorate
return func(self, *args, **kwargs)
File "/usr/local/bin/google_appengine/google/appengine/tools/dev_appserver.py", line 2375, in FindAndLoadModule
description)
File "/usr/local/bin/google_appengine/google/appengine/tools/dev_appserver.py", line 1538, in Decorate
return func(self, *args, **kwargs)
File "/usr/local/bin/google_appengine/google/appengine/tools/dev_appserver.py", line 2318, in LoadModuleRestricted
description)
File "/home/test/updatecheck.py", line 4, in <module>
from lxml.html import document_fromstring
File "/usr/local/bin/google_appengine/google/appengine/tools/dev_appserver.py", line 1538, in Decorate
return func(self, *args, **kwargs)
File "/usr/local/bin/google_appengine/google/appengine/tools/dev_appserver.py", line 2503, in load_module
return self.FindAndLoadModule(submodule, fullname, search_path)
File "/usr/local/bin/google_appengine/google/appengine/tools/dev_appserver.py", line 1538, in Decorate
return func(self, *args, **kwargs)
File "/usr/local/bin/google_appengine/google/appengine/tools/dev_appserver.py", line 2375, in FindAndLoadModule
description)
File "/usr/local/bin/google_appengine/google/appengine/tools/dev_appserver.py", line 1538, in Decorate
return func(self, *args, **kwargs)
File "/usr/local/bin/google_appengine/google/appengine/tools/dev_appserver.py", line 2318, in LoadModuleRestricted
description)
File "/usr/lib/python2.7/dist-packages/lxml/html/__init__.py", line 12, in <module>
from lxml import etree
ImportError: cannot import name etree
根據錯誤，似乎app引擎不允許我加載etree模塊出於某種原因。我想用lxml使用xpath，但我不能花太多時間來弄清楚這裏發生了什麼，也沒有足夠的python知識。所以我會試着找到一個'simpletree'版本的方式。
f = urllib2.urlopen("http://www.yahoo.com/").read()
p = html5lib.HTMLParser()
doc = p.parse(f)
# do something with doc.childNodes
self.response.out.write(len(doc.childNodes))
不是一個很好的方法，但至少它在我在現場谷歌應用程序引擎上測試時工作。
什麼版本的HTML5lib？在回購中，包含錯誤的行不再是行176，並且我無法看到當前版本中可能發生錯誤的任何方式，因爲該名稱將被定義，或者整個事件將因導入錯誤而失敗。 – geoffspear
很抱歉沒有及時回覆您。根據第13行的html5lib/__ init__.py，我認爲版本爲0.90 __version__ =「0.90」'。我剛剛通過pip安裝了庫，可能它是舊版本？ –
我得到這個錯誤，當我忘了把正確的條目在app.yaml，而不是使用2.3我用最新的 – semisided1