[Python-Dev] XML codec?

[M.-A. Lemburg]

On 2007-11-11 18:56, Martin v. Löwis wrote:
>> First, XML-RPC is not the only mechanism using XML over a network
>> connection. Second, you don't want to do this if you're dealing
>> with several 100 MB of data just because you want to figure
>> out the encoding.
> 
> That's my original claim/question: what SPECIFIC application do
> you have in mind that transfers XML over a network and where you
> would want to have such a stream codec?

XML-based web services used for business integration, e.g. based
on ebXML.

A common use case from our everyday consulting business is e.g.
passing market and trading data to portfolio pricing web services.

> If I have 100MB of XML in a file, using the detection API, I do
> 
>   f = open(filename)
>   s = f.read(100)
>   while True:
>     coding = xml.utils.detect_encoding(s)
>     if coding is not undetermined:
>        break
>     s += f.read(100)
>   f.close()
> 
> Having the loop here is paranoia: in my application, I might be
> able to know that 100 bytes are sufficient to determine the encoding
> always.

Doing the detection with files is easy, but that was never
questioned.

>>> Again, I don't see the use case. For XML-RPC, it's very feasible
>>> and standard procedure to have the entire document in memory
>>> (in a processed form).
>> You may not see the use case, but that doesn't really mean
>> anything if the use cases exist in real life applications,
>> right ?!
> 
> Right. However, I' will remain opposed to adding this to the
> standard library until I see why one would absolutely need to
> have that. Not every piece of code that is useful in some
> application should be added to the standard library.

Agreed, but the application space of web services is large
enough to warrant this.

-- 
Marc-Andre Lemburg
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