Unicode/UTF-8 confusion

Matt Nordhoff mnordhoff at mattnordhoff.com
Sat Mar 15 19:59:38 CET 2008


Tom Stambaugh wrote:
> I'm still confused about this, even after days of hacking at it. It's
> time I asked for help. I understand that each of you knows more about
> Python, Javascript, unicode, and programming than me, and I understand
> that each of you has a higher SAT score than me. So please try and be
> gentle with your responses.
>  
> I use simplejson to serialize html strings that the server is delivering
> to a browser. Since the apostrophe is a string terminator in javascript,
> I need to escape any apostrophe embedded in the html.
>  
> Just to be clear, the specific unicode character I'm struggling with is
> described in Python as:
> u'\N{APOSTROPHE}'}. It has a standardized utf-8 value (according to, for
> example, http://www.fileformat.info/info/unicode/char/0027/index.htm)
> of  0x27.
>  
> This can be expressed in several common ways:
> hex: 0x27
> Python literal: u"\u0027"
>  
> Suppose I start with some test string that contains an embedded
> apostrophe -- for example: u"   '   ". I believe that the appropriate
> json serialization of this is (presented as a list to eliminate notation
> ambiguities):
>  
> ['"', ' ', ' ', ' ', '\\', '\\', '0', '0', '2', '7', ' ', ' ', ' ', '"']
>  
> This is a 14-character utf-8 serialization of the above test string.
>  
> I know I can brute-force this, using something like the following:
> def encode(aRawString):
>     aReplacement = ''.join(['\\', '0', '0', '2', '7'])
>     aCookedString = aRawString.replace("'", aReplacement)
>     answer = simplejson.dumps(aCookedString)
>     return answer
>  
> I can't even make mailers let me *TYPE* a string literal for the
> replacement string without trying to turn it into an HTML link!
>  
> Anyway, I know that my "encode" function works, but it pains me to add
> that "replace" call before *EVERY* invocation of the simplejson.dumps()
> method. The reason I upgraded to 1.7.4 was to get the c-level speedup
> routine now offered by simplejson -- yet the need to do this apostrophe
> escaping seems to negate this advantage! Is there perhaps some
> combination of dumps keyword arguments, python encode()/str() magic, or
> something similar that accomplishes this same result?
>  
> What is the highest-performance way to get simplejson to emit the
> desired serialization of the given test string?

simplejson handles all necessary escaping of stuff like quotes...
-- 



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