On 21 August 2010 05:22, Mike Caron <[email protected]> wrote:
> On 8/20/2010 1:15 PM, Ralph Versteegen wrote:
>>
>> On 21 August 2010 05:11, James Paige<[email protected]> wrote:
>>>
>>> On Fri, Aug 20, 2010 at 12:55:50PM -0400, Mike Caron wrote:
>>>>
>>>> On 8/20/2010 12:52 PM, Ralph Versteegen wrote:
>>>>>
>>>>> On 21 August 2010 04:43, Mike Caron<[email protected]> wrote:
>>>>>>
>>>>>> On 8/20/2010 12:41 PM, Ralph Versteegen wrote:
>>>>>>>
>>>>>>> On 21 August 2010 03:58, Mike Caron<[email protected]> wrote:
>>>>>>>>
>>>>>>>> On 8/20/2010 11:45 AM, Ralph Versteegen wrote:
>>>>>>>>>
>>>>>>>>> On 21 August 2010 02:24, Mike Caron<[email protected]>
>>>>>>>>> wrote:
>>>>>>>>>>
>>>>>>>>>> On 8/20/2010 9:58 AM, Ralph Versteegen wrote:
>>>>>>>>>>>
>>>>>>>>>>> Currently reload2xml can't properly export binary data stored in
>>>>>>>>>>> strings in reload files. It would be nice to be able to hand edit
>>>>>>>>>>> xml
>>>>>>>>>>> and convert back. What's the preferred way to write binary?&#nnn;
>>>>>>>>>>> escape codes, or that Base64 stuff? (Is that actually part of the
>>>>>>>>>>> xml
>>>>>>>>>>> standard?)
>>>>>>>>>>
>>>>>>>>>> Strictly speaking, we only really need to escape characters below
>>>>>>>>>> 32.
>>>>>>>>>> Everything else should be okay to write out.
>>>>>>>>>
>>>>>>>>> Follow-up question: what about bytes above 127? Is there a chance
>>>>>>>>> of
>>>>>>>>> confusing xml parsers into guessing UTF8 encoding? I suppose it
>>>>>>>>> doesn't matter too much, since we can force libxml2 to read with
>>>>>>>>> ASCII
>>>>>>>>> encoding (but it would be nice to know that we have to do so).
>>>>>>>>
>>>>>>>> The best way to handle this, actually, would be to add the XML
>>>>>>>> header,
>>>>>>>> which
>>>>>>>> allows you to specify the encoding. In our case, it should look
>>>>>>>> something
>>>>>>>> like:
>>>>>>>>
>>>>>>>> <?xml version="1.0" encoding="iso-8859-1"?>
>>>>>>>>
>>>>>>>>>> In light of that, I would prefer the&#nnnn; syntax, since it means
>>>>>>>>>> that
>>>>>>>>>> no
>>>>>>>>>> one has to do any extra work to process the resulting XML file. If
>>>>>>>>>> you
>>>>>>>>>> used
>>>>>>>>>> Base64 (which has nothing to do with XML), you'd have to mark it
>>>>>>>>>> as
>>>>>>>>>> such
>>>>>>>>>> in
>>>>>>>>>> order to distinguish it from a regular string that just so happens
>>>>>>>>>> to
>>>>>>>>>> look
>>>>>>>>>> like Base64.
>>>>>>>>>
>>>>>>>>> OK, cool. I'll add that then soonish (unless you jumped on the
>>>>>>>>> chance to
>>>>>>>>> do so).
>>>>>>>>
>>>>>>>> No, go ahead.
>>>>>>>
>>>>>>> Change of plan required.
>>>>>>>
>>>>>>> ' "�" is not permitted, however, as the null character is one of
>>>>>>> the control characters excluded from XML, even when using a numeric
>>>>>>> character reference.[14] An alternative encoding mechanism such as
>>>>>>> Base64 is needed to represent such characters. ' - Wikipedia
>>>>>>>
>>>>>>> And I just confirmed libxml2 spits.
>>>>>>
>>>>>> Damn. I guess that kind of makes sense, though.
>>>>>>
>>>>>> Maybe... emit a<null/> element instead? Ugh.
>>>>>>
>>>>>> Or, Base64 it. Sigh.
>>>>>
>>>>> Well, I know next to nothing about XML, what's the idiomatic way to do
>>>>> that? Add a special attribute to nodes containing base64-encoded data,
>>>>> like<foo base="64">assdfasdf234</foo> ?
>>>>
>>>> No, the proper way to do this is something like this:
>>>>
>>>> <basenode xmlns:reload="http://hamsterrepublic.com/RELOAD";>
>>>> <foo reload:encoding="base64">...</foo>
>>>> </basenode>
>>>>
>>>> Note: that namespace URL doesn't have to exist, it just has to be
>>>> unique.
>>
>> At first I thought you may be pulling my leg and going overboard...
>> but such is XML!
>
> Actually, we could just cheese it and say:
>
> <root xmlns:reload="uri:reload">
>
> But, that's considered bad form.
>
> The only reason I'm suggesting using namespaces is because the structure and
> the data are intermingled. How is xml2reload supposed to know if base="64"
> means that the node is encoded, or it represents a strangely-based number,
> or that all your base count up to 64?
reload:base="64" would be perfectly unambiguous if it were agreed
upon, though. But I agree it would be pretty weird.
> Another, more XMLish way, might be to encode documents like this:
>
> <RELOADDocument>
> <node>
> <name>root</name>
> <type>null</type>
> <children>
> <node>
> <name>mynode</name>
> <type>string</type>
> <content>123</content>
> <children>...</children>
> </node>
> </children>
> </node>
> </RELOADDocument>
>
> Now who's pulling whose leg? ;)
Ugh I hate XML (and libxml) so much. I volunteered for this when I
thought it was going to be a quick fix with &#nnn; but now I'm in XML
deeper than I ever hoped to get in my life.
Anyway some more problems I'd like <s>approval</s> suggestions on:
* null-name nodes? We already use these in RELOAD documents. The
solution I came up with is to write the name as 'reload:_' and convert
it back to a null name in xml2reload (while still being able to
distinguish the null-name nodes libxml2 inserts). Was this a good
choice?
* strings with leading/trailing whitespace. xml2reload currently
strips it, but it doesn't have to. My first idea was:
<foo reload:encoding="exact"> lots of
white space <child>...</child>
<child>...</child>
</foo>
As you can see, the first child if any has to be smack against the end
of the string, while others can be indented normally
If that weren't bad enough, there's a complication. If the entire
string is whitespace, libxml2 discards it. So my suggestion is to
enclose the string in quotation marks. As a bonus, you can discard
whitespace after the end.
<foo reload:encoding="quoted">" lots of
white space "
<child>...</child>
<child>...</child>
</foo>
* Differentiating between zero-length strings and null valued nodes.
This would be solved by the above "quoted" encoding.
After all that's solved... a perfect XML representation of a RELOAD
document is still likely to produce a different document when
converted, because of differences in the string table. Oh well.
>>> Make it http://hamsterrepublic.com/ohrrpgce/RELOAD and I will make it a
>>> redirection to the reload docs.
>>>
>>> Does the xmlns:reload thing have to go in each and every enclosing
>>> parent node of a node that has base64?... or does it just go once in the
>>> root node?
>>>
>>> ---
>>> James
>>
>> I assume namespaces are meant to be in scope for all descendant nodes
>
> That is correct. The scope of namespaces works pretty much as you would
> expect.
>
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