The xslt_process() function is
the crux of the new XSLT extension. It allows you to perform
an XSLT transformation using almost any type of input source
- the containers. This is accomplished through the use of
argument buffers -- a concept taken from the Sablotron XSLT
processor (currently the only XSLT processor this extension
supports). The input containers default to a filename
'containing' the document to be processed. The result
container defaults to a filename for the transformed
document. If the result container is not specified - i.e. NULL - than the result is
returned.
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Containers can also be set via the $arguments array (see below).
The simplest type of transformation with the xslt_process() function is the transformation
of an XML file with an XSLT file, placing the result in a
third file containing the new XML (or HTML) document. Doing
this with sablotron is really quite easy...
While this functionality is great, many times,
especially in a web environment, you want to be able to print
out your results directly. Therefore, if you omit the third
argument to the xslt_process()
function (or provide a NULL value for the argument), it will
automatically return the value of the XSLT transformation,
instead of writing it to a file...
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The above two cases are the two simplest cases there are
when it comes to XSLT transformation and I'd dare say that
they are the most common cases, however, sometimes you get
your XML and XSLT code from external sources, such as a
database or a socket. In these cases you'll have the XML
and/or XSLT data in a variable -- and in production
applications the overhead of dumping these to file may be too
much. This is where XSLT's "argument" syntax, comes to the
rescue. Instead of files as the XML and XSLT arguments to the
xslt_process() function, you can
specify "argument place holders" which are then subsituted by
values given in the arguments array (5th parameter to the xslt_process() function). The following
is an example of processing XML and XSLT into a result
variable without the use of files at all.
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Finally, the last argument to the
xslt_process() function represents an array for any
top-level parameters that you want to pass to the XSLT
document. These parameters can then be accessed within your
XSL files using the xsl:param name="parameter_name"
instruction. The parameters must be UTF-8 encoded and their
values will be interpreted as strings by the Sablotron
processor. In other words - you cannot pass node-sets as
parameters to the XSLT document.
注: Please note that file:// is needed in front of path if you use Windows.