[lxml-dev] Target parser parsing error

[qhlonline]

Hi，
2009-06-03，"Stefan Behnel" <stefan_ml at behnel.de> ：
>qhlonline wrote:
>>    There are more informations about my parsing error when I use target
>> parser to parse http://www.jiayuan.com/ . The fatal error reported out
>> is: Input is not proper UTF-8, indicate encoding ! To find the real
>> place where this problem occured, I have tried to convert the HTML
>> string encoding with iconv directly. This time it also report error,
>> and the error character index in string is just the same with my lxml
>> test. Now things are clear that this parsing error is caused by
>> encoding conversion of iconv from utf-8 to utf-8 when there are illegal
>> characters in the source.
>
>What do you mean by "from utf-8 to utf-8" conversion?
I am not sure whether this conversion had taken place. But when I convert the html content string in this way. It will report illegal character error in some place of the string, and it is just the place where my lxml target parser generate error. Does it ensure that there are illegal characters in the html content? 
>
>> When I do not define the data function in my
>> target parser, It will paser without error report. Is it means that
>> when I escape the data function , the UTF-8 to UTF-8 conversion is
>> also escaped ? Or some correct conversion has been done before the call
>> to the data function ?
>
>It just means that the parser has ignored your character content. There
>are two levels here. The libxml2 parser will parse the byte stream and try
>to convert it to UTF-8. If that fails but it is asked to "recover" from
>it, it will just continue without raising an error. Not sure what becomes
>of the data in this case, but apparently there is no guarantee that the
>invalid bytes that were parsed up to this point get stripped.
>
I agree with you. I have thought about what libxml2 would do when an illegal character came. Your answer makes me clear at this point.
>The second level is where lxml comes into the play. When you define a
>"data()" method on your target parser, you ask lxml to pass you the
>character data from the document. lxml's SAX handler will then try to
>decode the UTF-8 data provided by the libxml2 parser to pass it into your
>method. If the data returned by the parser is not valid UTF-8, this will
>fail. I assume that this is where the exception that you see originates
>from, as this is done through the Python Codec API.
Yes, That is the case. But the illegal character came out side of lxml and outside of libxml2, The whole string was got from an URL by using urllib module in python. So, I wonder whether there were some other method to get HTML content from URL without illegal characters. 
>
>Does this clear things up?
Thank you for your help, I think I have learned more about lxml parsing process with your guidance. Thank you!
>
>That said, I could imagine letting the character decoder work around
>broken data if the "recover" option is enabled, simply by replacing broken
>content with a replacement character. This would improve the recovery
>capabilities in your case, without breaking the data any further than >already is.
>
>Stefan
>
Happy days！
                                         yours
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