Subject: Re: JSON-encoding strings in XSLT 2.0
From: Hermann Stamm-Wilbrandt <STAMMW@xxxxxxxxxx>
Date: Wed, 6 Nov 2013 15:18:28 +0100
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DataPower appliance had this cascade of regexp:relace() statements in the
past in stylesheet "store:///jsonx2json.xsl" for "<json:string>" escaping.
Customer raised a PMR on bad performance for JSONX <json:string>
conversions
to JSON (he proved by using stylesheet profiling).
I did fix that in this May fixpack by introducing new extension function
for doing the escaping in firmware rather than XSLT and just calling that
by
"dp:encode(., 'json-escape')":
http://www-01.ibm.com/support/docview.wss?uid=swg1IC90781
This improved conversion runtime for a 2.2MB JSONX customer sample file
with 740KB JSON output by a factor of 11.
So if you have to do JSON escaping in XSLT, you have no choice.
If not, then better do it in a new extension function.
Mit besten Gruessen / Best wishes,
Hermann Stamm-Wilbrandt
Level 3 support for XML Compiler team and Fixpack team lead
WebSphere DataPower SOA Appliances
https://www.ibm.com/developerworks/mydeveloperworks/blogs/HermannSW/
https://twitter.com/HermannSW/ http://www.stamm-wilbrandt.de/ce/
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From: Michael Kay <mike@xxxxxxxxxxxx>
To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx,
Date: 10/29/2013 12:46 PM
Subject: Re: JSON-encoding strings in XSLT 2.0
On 29 Oct 2013, at 11:02, Martynas Jusevihius <martynas@xxxxxxxxxxxx>
wrote:
> Thanks Michael. I was looking at http://json.org and here's what I came
up with:
>
> <xsl:template match="text()" mode="json-identity">
> <xsl:value-of
> select="replace(replace(replace(replace(replace(replace(., '\\',
> '\\\\'), '''', '\\'''), '"', '\\"'), '	', '\\t'),
> ' ', '\\n'), ' ', '\\r')"/>
> </xsl:template>
>
> Can this be improved?
Well, I'm not going to check that the list of characters to be escaped is
complete, but you've got the right idea. I would code it like this for
readability:
> <xsl:template match="text()" mode="json-identity">
<xsl:variable name="v" select="."/>
<xsl:variable name="v" select="replace($v, '\\', '\\\\')"/>
<xsl:variable name="v" select="replace($v, '"', '\\"')"/>
...
<xsl:value-of select="$v"/>
</xsl:variable>
or in 3.0 you can use the "!" operator for function chaining:
> <xsl:template match="text()" mode="json-identity">
<xsl:value-of select="replace(., '\\', '\\\\') ! replace(.,
'"', '\\"') ! ....."/>
</xsl:variable>
Michael Kay
Saxonica
> <xsl:value-of
> select="replace(replace(replace(replace(replace(replace(., '\\',
> '\\\\'), '''', '\\'''), '"', '\\"'), '	', '\\t'),
> ' ', '\\n'), ' ', '\\r')"/>
</xsl:template>
>
> On Tue, Oct 29, 2013 at 10:37 AM, Michael Kay <mike@xxxxxxxxxxxx> wrote:
>>
>> There's no built-in function for the job, but picking out the characters
=
>> that need special treatment (e.g. replacing newline by "\n") isn't =
>> difficult. Handling astral characters is a bit tricky because JSON =
>> requires them to be represented as a surrogate pair, but again the logic
=
>> for that isn't really difficult.
>>
>> Michael Kay
>> Saxonica
>>
>> On 29 Oct 2013, at 00:56, Martynas Jusevihius <martynas@xxxxxxxxxxxx>
wrote:
>>
>>> Hey,
>>>
>>> is there some way in XSLT 2.0 to encode strings for use in JSON? In my
>>> case, the stylesheet has to encode all text nodes in a XHTML fragment
>>> which then gets passed to WYSIWYM editor constructor. Could this be
>>> done as identity transform?
>>>
>>> I had solved this problem when I used XSLT 1.0 on PHP by calling
>>> json_encode() as extension function, but now I'm in the Java world.
>>> http://php.net/manual/en/function.json-encode.php
>>>
>>> Martynas
>>> graphityhq.com
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