我该如何解决不能使用BeautifulSoup和Bottle调用NoneType对象的问题？

Question

我在一个小Bottle项目的一条路线中包含以下代码：

@route('/method/')
def method():
    import urllib.request
    from bottle import response
    response.content_type = 'text/xml'

    opener = urllib.request.build_opener()
    opener.addheaders = [('User-agent', 'Mozilla/5.0')]
    r=opener.open('http://www.example.com/')
    content = str(r.read())
    soup = BeautifulSoup(content)
    return soup.title

我读过类似的问题。 我已经尝试了所有方法，但始终遇到相同的错误。 我什至不知道它是否与瓶子有关。

我已经使用virtualenv用Python3创建了一个隔离的环境。 BeautifulSoup的版本为4：

from bs4 import BeautifulSoup

我总是得到相同的，巨大的堆栈跟踪：

127.0.0.1 - - [24/Jan/2015 14:50:42] "GET /extract_web_information/ HTTP/1.1" 200 0
Traceback (most recent call last):
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 179, in finish_response
    for data in self.result:
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/util.py", line 30, in __next__
    data = self.filelike.read(self.blksize)
TypeError: 'NoneType' object is not callable

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 138, in run
    self.finish_response()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 183, in finish_response
    self.close()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/simple_server.py", line 38, in close
    SimpleHandler.close(self)
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 321, in close
    self.result.close()
TypeError: 'NoneType' object is not callable
127.0.0.1 - - [24/Jan/2015 14:50:42] "GET /extract_web_information/ HTTP/1.1" 500 59
----------------------------------------
Exception happened during processing of request from ('127.0.0.1', 55533)
Traceback (most recent call last):
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 179, in finish_response
    for data in self.result:
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/util.py", line 30, in __next__
    data = self.filelike.read(self.blksize)
TypeError: 'NoneType' object is not callable

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 138, in run
    self.finish_response()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 183, in finish_response
    self.close()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/simple_server.py", line 38, in close
    SimpleHandler.close(self)
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 321, in close
    self.result.close()
TypeError: 'NoneType' object is not callable

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 141, in run
    self.handle_error()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 368, in handle_error
    self.finish_response()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 180, in finish_response
    self.write(data)
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 274, in write
    self.send_headers()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 331, in send_headers
    if not self.origin_server or self.client_is_modern():
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 344, in client_is_modern
    return self.environ['SERVER_PROTOCOL'].upper() != 'HTTP/0.9'
TypeError: 'NoneType' object is not subscriptable

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/socketserver.py", line 305, in _handle_request_noblock
    self.process_request(request, client_address)
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/socketserver.py", line 331, in process_request
    self.finish_request(request, client_address)
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/socketserver.py", line 344, in finish_request
    self.RequestHandlerClass(request, client_address, self)
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/socketserver.py", line 669, in __init__
    self.handle()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/simple_server.py", line 133, in handle
    handler.run(self.server.get_app())
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 144, in run
    self.close()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/simple_server.py", line 35, in close
    self.status.split(' ',1)[0], self.bytes_sent
AttributeError: 'NoneType' object has no attribute 'split'
----------------------------------------
127.0.0.1 - - [24/Jan/2015 14:50:42] "GET /extract_web_information/ HTTP/1.1" 200 0
Traceback (most recent call last):
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 179, in finish_response
    for data in self.result:
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/util.py", line 30, in __next__
    data = self.filelike.read(self.blksize)
TypeError: 'NoneType' object is not callable

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 138, in run
    self.finish_response()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 183, in finish_response
    self.close()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/simple_server.py", line 38, in close
    SimpleHandler.close(self)
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 321, in close
    self.result.close()
TypeError: 'NoneType' object is not callable
127.0.0.1 - - [24/Jan/2015 14:50:42] "GET /extract_web_information/ HTTP/1.1" 500 59
----------------------------------------
Exception happened during processing of request from ('127.0.0.1', 55536)
Traceback (most recent call last):
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 179, in finish_response
    for data in self.result:
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/util.py", line 30, in __next__
    data = self.filelike.read(self.blksize)
TypeError: 'NoneType' object is not callable

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 138, in run
    self.finish_response()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 183, in finish_response
    self.close()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/simple_server.py", line 38, in close
    SimpleHandler.close(self)
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 321, in close
    self.result.close()
TypeError: 'NoneType' object is not callable

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 141, in run
    self.handle_error()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 368, in handle_error
    self.finish_response()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 180, in finish_response
    self.write(data)
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 274, in write
    self.send_headers()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 331, in send_headers
    if not self.origin_server or self.client_is_modern():
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 344, in client_is_modern
    return self.environ['SERVER_PROTOCOL'].upper() != 'HTTP/0.9'
TypeError: 'NoneType' object is not subscriptable

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/socketserver.py", line 305, in _handle_request_noblock
    self.process_request(request, client_address)
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/socketserver.py", line 331, in process_request
    self.finish_request(request, client_address)
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/socketserver.py", line 344, in finish_request
    self.RequestHandlerClass(request, client_address, self)
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/socketserver.py", line 669, in __init__
    self.handle()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/simple_server.py", line 133, in handle
    handler.run(self.server.get_app())
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 144, in run
    self.close()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/simple_server.py", line 35, in close
    self.status.split(' ',1)[0], self.bytes_sent
AttributeError: 'NoneType' object has no attribute 'split'
----------------------------------------
127.0.0.1 - - [24/Jan/2015 14:50:42] "GET /extract_web_information/ HTTP/1.1" 200 0
Traceback (most recent call last):
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 179, in finish_response
    for data in self.result:
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/util.py", line 30, in __next__
    data = self.filelike.read(self.blksize)
TypeError: 'NoneType' object is not callable

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 138, in run
    self.finish_response()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 183, in finish_response
    self.close()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/simple_server.py", line 38, in close
    SimpleHandler.close(self)
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 321, in close
    self.result.close()
TypeError: 'NoneType' object is not callable
127.0.0.1 - - [24/Jan/2015 14:50:42] "GET /extract_web_information/ HTTP/1.1" 500 59
----------------------------------------
Exception happened during processing of request from ('127.0.0.1', 55539)
Traceback (most recent call last):
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 179, in finish_response
    for data in self.result:
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/util.py", line 30, in __next__
    data = self.filelike.read(self.blksize)
TypeError: 'NoneType' object is not callable

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 138, in run
    self.finish_response()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 183, in finish_response
    self.close()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/simple_server.py", line 38, in close
    SimpleHandler.close(self)
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 321, in close
    self.result.close()
TypeError: 'NoneType' object is not callable

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 141, in run
    self.handle_error()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 368, in handle_error
    self.finish_response()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 180, in finish_response
    self.write(data)
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 274, in write
    self.send_headers()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 331, in send_headers
    if not self.origin_server or self.client_is_modern():
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 344, in client_is_modern
    return self.environ['SERVER_PROTOCOL'].upper() != 'HTTP/0.9'
TypeError: 'NoneType' object is not subscriptable

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/socketserver.py", line 305, in _handle_request_noblock
    self.process_request(request, client_address)
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/socketserver.py", line 331, in process_request
    self.finish_request(request, client_address)
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/socketserver.py", line 344, in finish_request
    self.RequestHandlerClass(request, client_address, self)
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/socketserver.py", line 669, in __init__
    self.handle()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/simple_server.py", line 133, in handle
    handler.run(self.server.get_app())
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/handlers.py", line 144, in run
    self.close()
  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/wsgiref/simple_server.py", line 35, in close
    self.status.split(' ',1)[0], self.bytes_sent
AttributeError: 'NoneType' object has no attribute 'split'
----------------------------------------

我如何运行服务器

source bin/activate
python myserver.py

After that, GET request from a browser

我已测试该请求是否正确发出。

非常感谢，

Answer 1

也许没有<title> 。 为了说明这一点，请尝试替换您的代码

return soup.title

有：

return soup.title or "no title found."