如何處理lxml中的編碼以正確解析html-string？

Question

我有一個xml file。請下載並保存爲blog.xml。 這是我的文件在谷歌博客的列表，我寫了一些代碼來解析它，有一些與lxml扭曲的東西。

代碼1：

from stripogram import html2text 
import feedparser 
d = feedparser.parse('blog.xml') 
for num,entry in enumerate(d.entries): 
    string=entry.content[0]['value'].encode("utf-8") 
    print html2text(string) 

它獲得與編碼1一個正確的結果。

碼2：

import lxml.html 
import feedparser 
d = feedparser.parse('blog.xml') 
for num,entry in enumerate(d.entries): 
    string=entry.content[0]['value'] 
    myhtml=lxml.html.document_fromstring(string) 
    print myhtml.text_content() 

它獲得與CODE2一個錯誤的輸出。

Traceback (most recent call last): 
    File "<stdin>", line 3, in <module> 
    File "/usr/lib/python2.7/dist-packages/lxml/html/__init__.py", line 532, in document_fromstring 
    value = etree.fromstring(html, parser, **kw) 
    File "lxml.etree.pyx", line 2754, in lxml.etree.fromstring (src/lxml/lxml.etree.c:54631) 
    File "parser.pxi", line 1569, in lxml.etree._parseMemoryDocument (src/lxml/lxml.etree.c:82659) 
ValueError: Unicode strings with encoding declaration are not supported. 

CODE3：

import lxml.html 
import feedparser 
d = feedparser.parse('blog.xml') 
for num,entry in enumerate(d.entries): 
    string=entry.content[0]['value'].encode("utf-8") 
    myhtml=lxml.html.document_fromstring(string) 
    print myhtml.text_content() 

它獲得與CODE3一個錯誤的輸出。

Traceback (most recent call last): 
    File "<stdin>", line 3, in <module> 
    File "/usr/lib/python2.7/dist-packages/lxml/html/__init__.py", line 532, in document_fromstring 
    value = etree.fromstring(html, parser, **kw) 
    File "lxml.etree.pyx", line 2754, in lxml.etree.fromstring (src/lxml/lxml.etree.c:54631) 
    File "parser.pxi", line 1578, in lxml.etree._parseMemoryDocument (src/lxml/lxml.etree.c:82748) 
    File "parser.pxi", line 1457, in lxml.etree._parseDoc (src/lxml/lxml.etree.c:81546) 
    File "parser.pxi", line 965, in lxml.etree._BaseParser._parseDoc (src/lxml/lxml.etree.c:78216) 
    File "parser.pxi", line 569, in lxml.etree._ParserContext._handleParseResultDoc (src/lxml/lxml.etree.c:74472) 
    File "parser.pxi", line 650, in lxml.etree._handleParseResult (src/lxml/lxml.etree.c:75363) 
    File "parser.pxi", line 599, in lxml.etree._raiseParseError (src/lxml/lxml.etree.c:74827) 
lxml.etree.XMLSyntaxError: line 1395: Tag b:include invalid 

如何處理lxml中的編碼以正確解析html-string？

Answer 1

There is a bug in lxml。 檢查這個代碼的輸出：

import lxml.html 
import feedparser 

def test(): 
    try: 
     lxml.html.document_fromstring('') 
    except Exception as e: 
     print e 

d = feedparser.parse('blog.xml') 
e = d.entries[0].content[0]['value'].encode('utf-8') 

test() # XMLSyntaxError: None 

lxml.html.document_fromstring(e) 
test() # XMLSyntaxError: line 1407: Tag b:include invalid 

因此錯誤是混亂的，爲什麼你的分析失敗的真正原因是，你傳遞空字符串document_fromstring。

試試這個代碼：

import lxml.html 
import feedparser 
d = feedparser.parse('blog.xml') 
for num,entry in enumerate(d.entries): 
    string=entry.content[0]['value'].encode("utf-8") 
    if not string: 
     continue 
    myhtml=lxml.html.document_fromstring(string) 
    print myhtml.text_content() 

Answer 2

你可以自己創建一個解析器，而不是使用document_fromstring：

from cStringIO import StringIO 
from lxml import etree 

for num, entry in enumerate(d.entries): 
    text = entry.content[0]['value'].encode('utf8') 
    parser = etree.HTMLParser() 
    tree = etree.parse(StringIO(text), parser) 
    print ''.join(tree.xpath('.//text()')) 

Blogger.com的Atom提要出口，這部作品打印.content[0].value條目的文本內容。