在抓取网页时如何处理未知的编码? [英] How to deal with unknown encoding when scraping webpages?
问题描述
我一次刮一篇文章url的代码导致出现以下错误:
UnicodeDecodeError:'ascii'编解码器无法解码8858位的字节0xe2:ordinal不在范围内(128)
以下是我的代码的最简单形式:
from google.appengine.api import urlfetch
def fetch(url):
headers = {'User-Agent':Chrome / 11.0.696.16 }
result = urlfetch.fetch(url,headers)
if result.status_code == 200:
return result.content
以下是我尝试过的另一个变体,结果相同:
def fetch(url):
headers = {'User-Agent':Chrome / 11.0.696.16}
result = urlfetch.fetch(url,headers)
if result.status_code == 200:
s = result.content
s = s.decode(' utf-8')
s = s.encode('utf-8')
s = unicode(s,'utf-8')
返回s
这是丑陋而脆弱的一个,它也不起作用:
<$ p $ ($ url):
headers = {'User-Agent':Chrome / 11.0.696.16}
result = urlfetch.fetch(url,headers)
if result.status_code == 200:
s = result.content
try:
s = s.decode('iso-8859-1')
除了:
通过
试试:
s = s.decode('ascii')
除外:
通过
试试:
s = s。解码('GB2312')
除外:
通过
试试:
s = s.decode('Windows-1251')
除外:
pass
尝试:
s = s.decode('Windows-1252')
除外:
s =无效
s = s.encode('utf-8')
s = unicode(s,'utf-8')
返回s
最后一个变量返回s,因为字符串没有工作,除去。
所以,我要去不得不扩大我笨拙的尝试/除了构造包含所有可能的编码(即使工作?),还是有一个更简单的方法?
为什么我决定刮掉整个HTML,不只是BeautifulSoup?因为我想在稍后进行修剪,以避免GAE中的DeadlineExceedError。
我读过关于Unicode的所有优秀文章,以及它应该如何完成?是。然而,我没有找到一个解决方案,并不假设我知道传入的编码,我不这样做,因为我每天都在拼抢不同的网站。
前段时间我有同样的问题,没有100%准确。我做的是:
$ b $ ul
从内容类型获取编码
从元标记获取编码
I'm scraping news articles from various sites, using GAE and Python.
The code where I scrape one article url at a time leads to the following error:
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in position 8858: ordinal not in range(128)
Here's my code in its simplest form:
from google.appengine.api import urlfetch
def fetch(url):
headers = {'User-Agent' : "Chrome/11.0.696.16"}
result = urlfetch.fetch(url,headers)
if result.status_code == 200:
return result.content
Here is another variant I have tried, with the same result:
def fetch(url):
headers = {'User-Agent' : "Chrome/11.0.696.16"}
result = urlfetch.fetch(url,headers)
if result.status_code == 200:
s = result.content
s = s.decode('utf-8')
s = s.encode('utf-8')
s = unicode(s,'utf-8')
return s
Here's the ugly, brittle one, which also doesn't work:
def fetch(url):
headers = {'User-Agent' : "Chrome/11.0.696.16"}
result = urlfetch.fetch(url,headers)
if result.status_code == 200:
s = result.content
try:
s = s.decode('iso-8859-1')
except:
pass
try:
s = s.decode('ascii')
except:
pass
try:
s = s.decode('GB2312')
except:
pass
try:
s = s.decode('Windows-1251')
except:
pass
try:
s = s.decode('Windows-1252')
except:
s = "did not work"
s = s.encode('utf-8')
s = unicode(s,'utf-8')
return s
The last variant returns s as the string "did not work" from the last except.
So, am I going to have to expand my clumsy try/except construction to encompass all possible encodings (will that even work?), or is there an easier way?
Why have I decided to scrape the entire html, not just the BeautifulSoup? Because I want to do the soupifying later, to avoid DeadlineExceedError in GAE.
Have I read all the excellent articles about Unicode, and how it should be done? Yes. However, I have failed to find a solution that does not assume I know the incoming encoding, which I don't, since I'm scraping different sites every day.
I had the same problem some time ago and there is nothing 100% accurate. What I did was:
- Get encoding from Content-Type
- Get encoding from meta tags
- Detect encoding with chardet Python module
- Decode text from the most common encoding to Unicode
- Process the text/html
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