xslt_set_scheme_handler
Here's some useful information I found in the PHP 4.3.4 source (in the file ext/xslt/README.XSLT-BACKENDS):
void xslt_set_scheme_handlers(resource processor, array handlers)
Registers the scheme handlers for the document (aka XPath handlers), given a XSLT processor resource (allocated by xslt_create()) and an array in the following format:
array(
"get_all" => function,
"open" => function,
"get" => function,
"put" => function,
"close" => function
)
Where function is either a function name or an array in the following format:
array(&$obj, "method")
Note: You do not need to handle the array(&$obj, method") syntax by yourself as this is handled in the C call_xslt_function() library function (and more specifically, Zend's call_user_function_ex() function.
Note: The given array does not need to contain all of the different scheme handler elements (although it can), but it only needs to conform to the "handler" => "function" format described above.
Each of the individual scheme handler functions called are in the formats below:
string get_all(resource processor, string scheme, string rest)
resource open(resource processor, string scheme, string rest)
int get(resource processor, resource fp, string &data)
int put(resource processor, resource fp, string data)
void close(resource processor, resource fp)
xslt_set_scheme_handlers
(PHP 4 >= 4.0.6)
xslt_set_scheme_handlers — Set the scheme handlers for the XSLT processor
Description
void xslt_set_scheme_handlers
( resource $xh
, array $handlers
)
Registers the scheme handlers (XPath handlers) for the document.
Parameters
- xh
-
The XSLT processor link identifier, created with xslt_create().
- handlers
-
An array with the following keys: "get_all", "open", "get", "put", and "close".
Every entry must be a function name or an array in the following format: array($obj, "method").
Note that the given array does not need to contain all of the different scheme handler elements (although it can), but it only needs to conform to the "handler" => "function" format described above.
Each of the individual scheme handler functions called are in the formats below:
string get_all(resource processor, string scheme, string rest) resource open(resource processor, string scheme, string rest) int get(resource processor, resource fp, string &data) int put(resource processor, resource fp, string data) void close(resource processor, resource fp)
Return Values
No value is returned.
Examples
Example #1 xslt_set_scheme_handlers() example
For example, here is an implementation of the "file_exists()" PHP function.
<?php
// Definition of the handler
function mySchemeHandler($processor, $scheme, $rest)
{
$rest = substr($rest,1); // to remove the first / automatically added by the engine
if ($scheme == 'file_exists') {
// result is embedded in a small xml string
return '<?xml version="1.0" encoding="UTF-8"?><root>' . (file_exists($rest) ? 'true' : 'false') . '</root>';
}
}
$SchemeHandlerArray = array('get_all' => 'mySchemeHandler');
// Start the engine
$params = array();
$xh = xslt_create();
xslt_set_scheme_handlers($xh, $SchemeHandlerArray);
$result = xslt_process($xh, "myFile.xml", "myFile.xsl", NULL, array(), $params);
xslt_free($xh);
echo $result;
?>
Then, inside the stylesheet, you can test whether a certain file exists with:
<xsl:if test="document('file_exists:anotherXMLfile.xml')/root='true'">
<!-- The file exist -->
</xsl:if>
add a note
User Contributed Notesxslt_set_scheme_handlers
cchittleborough at cluemail dot com
13-Sep-2004 03:36
13-Sep-2004 03:36
ohlesbeauxjours at yahoo dot fr
20-Mar-2003 08:49
20-Mar-2003 08:49
xslt_set_scheme_handlers is a powerful feature, derived from the Sablotron engine, which can help in various situations.
Briefly, it allows you to call any kind of PHP instruction, during the treatment of a stylesheet, through the XSLT document() function.
For example, here is an implementation of the "file_exists()" PHP function :
// Definition of the handler :
function mySchemeHandler($processor, $scheme, $rest) {
$rest=substr($rest,1); // to remove the first / automatically added by the engine
if($scheme == 'file_exists')
return '<?xml version="1.0" encoding="UTF-8"?><root>'.(file_exists($rest) ? "true" : "false")."</root>";
// result is embedded in a small xml string
}
// Initialisation of the handler (the "get_all" should be work in most cases) :
$SchemeHandlerArray = array();
$SchemeHandlerArray["get_all"] = "mySchemeHandler";
// Start the engine :
$params = array();
$xh = xslt_create();
xslt_set_scheme_handlers($xh,$SchemeHandlerArray);
$result = xslt_process($xh,"myFile.xml","myFile.xsl",NULL,array(),$params);
xslt_free($xh);
echo $result;
Then, inside the stylesheet, you can test whether a certain file exists with :
<xsl:if test="document('file_exists:anotherXMLfile.xml’)/root='true'">
< !-- bla bla bla -->
</xsl:if>
So finally, the principle is simple :
- you define a scheme (here, I called it "file_exists")
- you write the action associated to that scheme (in the mySchemeHandler function)
- you embed the (probable) results in an XML string, that you return.
- and in the stylesheet, you check : document('myPersonalURIscheme:myXPath')
You can imagine many other uses for the mySchemeHandler() function.
My framework is : PHP 4.2.3, Sablotron version 0.96, and Expat 1.95.5
Please note that some older version of PHP might require an additionnal parameter :
mySchemeHandler($processor,$scheme,$rest,&$buffer)
and you place your XML in $buffer, instead of returning it with return().
Baptiste