I have an xml:
<mynodes>
<mynode>
<element1>a</element1>
<element2>b</element2>
</mynode>
<mynode>
<element1>c</element1>
<element2>d</element2>
</mynode>
</mynodes>
<translation>
<col>element2</col>
<cont>d</cont>
</translation>
I need an xpath, which gives me the the element1 content of the same subnode.
I have tried different xpaths, always with error.
My idea was to:
<xsl:variable name="col" select="/translation/col" />
<xsl:variable name="cont" select="/translation/cont" />
<xsl:value-of select="/mynodes/mynode[./name()=$col and ./text()=$cont]/element1" />
I have tried many things. Any idea?
I did not want to loop the structure, because the structure is quite big and there are several queries to do.
Use <xsl:value-of select="/mynodes/mynode[*[name()=$col and . = $cont]]/element1"/>
XSLT has a built-in key mechanism for resolving cross-references - and it would be best to use it, esp. if you have "several queries to do".
Here you could define the key as:
<xsl:key name="k1" match="*" use="concat(name(), '|', .) " />
and then call it from the context of translation as::
<xsl:value-of select="key('k1', concat($col, '|', $cont))/../element1"/>
Related
I'm doing an xslt transform that generates a sql statement for me. The way I'm using below is not working. Is there a way?
<xsl:template match="foo">
<xsl:variable name="var1" select="#att_val1" />
select $var1.* from $var1
</xsl:template>
I know it will work if I do this:
<xsl:template match="foo">
select <xsl:value-of select="#att_val1" />.* from <xsl:value-of select="#att_val1" />
</xsl:template>
In XSLT 1.0, variable references are recognized in XPath expressions, but not in general template text. To evaluate an XPath expression and output the result as a text node in the result tree, use xsl:value-of, as you already know how to do. Example:
<xsl:template match="foo">
<xsl:variable name="var1" select="#att_val1" />
select <xsl:value-of select="$var1"/>.* from <xsl:value-of select="$var1"/>
</xsl:template>
Alternatively, you could build the whole select command in one xsl:value-of with use of the concat() function.
Unless you move to XSLT 3.0 (https://www.w3.org/TR/xslt-30/#text-value-templates) where you can do e.g. <xsl:template match="foo" expand-text="yes">select {#att_val1}.* from {#att_val1}</xsl:template> you will have to use your second option or perhaps a <xsl:template match="foo"><xsl:value-of select="concat('select ', #att_val1, '.* from ', #att_val1)"/></xsl:template>, but there is certainly no way in XSLT 1.0 to avoid the use of xsl:value-of completely.
I'm trying to access a variable from within a for-each. I've done a lot of reading today to try to figure this out, but nothing quite fits my scenario. Eventually, I will have multiple series like seen below and I will use the variables that I'm pulling out and make different condition. The for-each that I have below is bringing back data from 400 records. I'm sorry, I cannot provide an XML. I'm not able to expose GUIDs and such.
UPDATE
<?xml version="1.0"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output media-type="xml" indent="yes"/>
<xsl:template match="/">
<Records>
<xsl:for-each select="Records/Record/Record[#levelGuid = 'level1']">
<xsl:variable name="rocName1" select="Field[#guid = '123']"/>
<xsl:variable name ="rocName2" select="substring-before($rocName1, ' - ')"/>
</xsl:for-each>
<xsl:for-each select="Records/Record/Record[#levelGuid = 'levelA']">
<xsl:variable name ="findingName" select="Field[#guid = '123']"/>
<xsl:variable name="findingName1" select="substring-after($findingName, ': ')"/>
<xsl:variable name="findingName2" select="substring-after($findingName1, 'PCIDSSv3.1:')"/>
</xsl:for-each>
<xsl:if test="$findingName1 = $rocName1">
<Records>
<findingID>
<xsl:for-each select="Records/Record/Record[#levelGuid = '123']">
<xsl:value-of select ="Field[#guid = '123']"/>
</xsl:for-each>
</findingID>
</Records>
</xsl:if>
</Records>
</xsl:template>
</xsl:stylesheet>
The desired output is any findingID that has a $findingName1 that equals $rocName1. The GUIDS only appear once, but each level has hundreds of records.
I'm trying to access a variable from within a for-each.
The variable $rocRecord is in scope inside the for-each. You can simply reference it and use it.
But I think you are trying to do something else. I.e., defining a variable inside for-each and wanting to use it outside it.
Variables are scoped within their focus-setting containing block. So the short answer is: you cannot do it. The long answer however...
Use templates. The only reason to do what you seem to want to be doing is to need to access the data elsewhere:
<xsl:template match="/">
<!-- in fact, you don't need for-each at all, but I leave it in for clarity -->
<xsl:for-each select="records/record">
<!--
apply-templates means: call the declared xsl:template that
matches this node, it is somewhat similar to a function call in other
languages, except that it works the other way around, the processor will
magically find the "function" (i.e., template) for you
-->
<xsl:apply-templates select="Field[#guid='123']" />
</xsl:for-each>
</xsl:template>
<xsl:template match="Field">
<!-- the focus here is what is the contents of your variable $rocName1 -->
<rocName>
<xsl:value-of select="substring=-before(., ' - ')" />
</rocName>
</xsl:template>
XSLT is a declarative, template-oriented, functional language with concepts that are quite unique compared to most other languages. It can take a few hours to get used to it.
You said you did a lot of reading, but perhaps it is time to check a little XSLT course? There are a few online, search for "XSLT fundamentals course". It will save you hours / days of frustration.
This is a good, short read to catch up on variables in XSLT.
Update
On second read, I think it looks like you are troubled by the fact that the loop goes on for 400 items and that you only want to output the value of $rocName1. The example I showed above, does exactly that, because apply-templates does nothing if the selection is empty, which is what happens if the guid is not found.
If the guid appears once, the code above will output it once. If it appears multiple times and you only want the first, append [1] to the select statement.
Update #2 (after your update with an example)
You have two loops:
<xsl:for-each select="Records/Record/Record[#levelGuid = 'level1']">
and
<xsl:for-each select="Records/Record/Record[#levelGuid = 'levelA']">
You then want to do something (created a findingId) when a record in the first loop matches a record in the second loop.
While you can solve this using (nested) loops, it is not necessary to do so, in fact, it is discouraged as it will make your code hard to read. As I explained in my original answer, apply-templates is usually the easier way to do get this to work.
Since the Record elements are siblings of one another, I would tackle this as follows:
<xsl:template match="/">
<Records>
<xsl:apply-templates select="Records/Records/Record[#levelGuid = 'level1']" />
</Records>
</xsl:template>
<xsl:template match="Record">
<xsl:variable name="rocName1" select="Field[#guid = '123']"/>
<xsl:variable name ="rocName2" select="substring-before($rocName1, ' - ')"/>
<xsl:variable name="findingNameBase" select="../Record[#levelGuid = 'levelA']" />
<xsl:variable name ="findingName" select="$findingNameBase/Field[#guid = '123']"/>
<xsl:variable name="findingName1" select="substring-after($findingName, ': ')"/>
<xsl:variable name="findingName2" select="substring-after($findingName1, 'PCIDSSv3.1:')"/>
<findingId rocName="{$rocName1}">
<xsl:value-of select="$findingName" />
</findingId>
</xsl:template>
While this can be simplified further, it is a good start to learn about applying templates, which is at the core of anything you do with XSLT. Learn about applying templates, because without it, XSLT will be very hard to understand.
I do a XSLT to HTML transformation using the method recommended in Qt doc:
QXmlQuery query(QXmlQuery::XSLT20);
query.setFocus(QUrl("myInput.xml"));
query.setQuery(QUrl("myStylesheet.xsl"));
query.evaluateTo(out);
Inside XSLT I use generate-id() method to generate unique ids for different DIV blocks. It works perfectly in Qt4.8, but not in Qt5.4
¿Anyone knows a reason for that, and how to solve this?
Edit: I get no error. What I get in Qt5 is always the same ID, while in Qt4 I get a different, unique ID each time i call generate-id().
I generate the ID this way:
<xsl:variable name="tc_id" select="generate-id()"/>
And I use it this way:
<xsl:value-of select="$tc_id"/>
This is the cpp code doing the transformation:
// generate output string
QXmlQuery query(QXmlQuery::XSLT20);
QString output;
query.setFocus(QUrl(_final_output_filepath.c_str()));
query.setQuery(xslt_code.c_str());
query.evaluateTo(&output);
Edit 2:
When I use this code...
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:fo="http://www.w3.org/1999/XSL/Format"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:fn="http://www.w3.org/2005/xpath-functions"
xmlns:xdt="http://www.w3.org/2005/xpath-datatypes">
<xsl:template match="/">
<xsl:for-each select="trial/testsuite">
<xsl:for-each select="testcase">
<xsl:variable name="tc_index" select="position()"/>
<xsl:variable name="tc_id" select="generate-id(.)"/>
<xsl:value-of select="$tc_id"/>
</xsl:for-each>
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>
...I get always the same ID.
<xsl:template match="/">
<xsl:value-of select="generate-id()"/> --
<xsl:value-of select="generate-id()"/> --
<xsl:value-of select="generate-id()"/>
Thanks for the snippet. This was indeed why I kept bugging you about giving a reproducible example.
What happens here is that you call the generate-id() function multiple times without changing the context node. The default argument for this function is the context node (here: /, or the root node).
Unless you change the context node, this function is deliberately designed to be stable. That means that, if called repeatedly with the same argument (also meaning: the same default argument, the same context), it must return the same string.
It is also designed such that it always returns a unique string per distinct node. Two nodes are distinct if they have different position in the document (i.e., they are distinct even if they look the same, but appear on multiple places).
Bottom line: you didn't hit a bug in the Qt implementation of XSLT 2.0, but you hit a resolved issue that was a bug and was incidentally used as a feature.
If you require a unique ID in XSLT 2.0, and you are bound to giving the same context, there is probably something else that changes: for instance, you can be in a loop going over a set of numbers or strings. You can use this info to create a unique string.
Another "hack" in XSLT 2.0 is to use a single point in the specification where determinism is not guaranteed: on creation of new nodes:
<xsl:function name="my:gen-id" as="xs:string">
<xsl:sequence select="generate-id(my:gen-id-getnode())" />
</xsl:function>
<xsl:function name="my:gen-id-getnode" as="element()">
<node />
</xsl:function>
This small function touches on some advanced concepts and recently, people discussing in the XSL Working Group, have agreed that optimizing away the creation of the new node is allowed if the node identity is not required. Whether or not a processor correctly detects this is unclear.
In XSLT 3.0 a new property has been introduced on xsl:function: #new-each-time, which informs the processor that the function should be evaluated each time and not get inlined.
Update: tests with Qt 5.5 or 5.4
I have tested a variant of your code with Qt because I couldn't believe that identity (which is a core concept of XSLT) doesn't work with it. So, I created a document with similar-looking nodes of all six types (I ignored namespace nodes, as support for it is optional).
Input test document
<root test="bla">
<?pi do-something ?>
<row></row>
<!-- comment here -->
<row>content</row>
<row>content</row>
<row id="bla" xml:id="bla">content</row>
</root>
XSLT 2.0 code
Code slightly adjusted due to Qt not supporting #separator correctly.
<xsl:stylesheet
xmlns:my="my-functions"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="2.0">
<xsl:strip-space elements="*"/>
<xsl:template match="node()|#*">
<xsl:value-of select="string-join(
('gen-id(',
my:decorate(.), '[', my:depth(.), ']', ') = ', generate-id(.),
'
'), '')" />
<xsl:apply-templates select="#*|node()" />
</xsl:template>
<!-- remove prev. and use this if you think for-each is different -->
<!--xsl:template match="/">
<xsl:for-each select="//node() | //#*">
<xsl:value-of select="string-join(
('gen-id(',
my:decorate(.), '[', my:depth(.), ']', ') = ', generate-id(.),
'
'), '')" />
</xsl:for-each>
</xsl:template-->
<xsl:function name="my:depth" as="xs:string">
<xsl:param name="node" />
<xsl:sequence select="
string(count($node/(/)//node()[$node >> .]) + 1)" />
</xsl:function>
<xsl:function name="my:decorate">
<xsl:param name="node" />
<xsl:sequence select="
($node/self::text(), 'text')[2],
($node/self::element(), concat('Q{}', name($node)))[2],
($node/self::document-node(), 'document')[2],
($node/self::comment(), 'comment')[2],
($node/self::attribute(), concat('#', name($node)))[2],
($node/self::processing-instruction(), 'processing-instruction')[2]
" />
</xsl:function>
</xsl:stylesheet>
Output using Exselt
gen-id(Q{}root[1]) = x1e2
gen-id(#test[2]) = x1e2a0
gen-id(processing-instruction[2]) = x1p3
gen-id(Q{}row[3]) = x1e4
gen-id(comment[4]) = x1c5
gen-id(Q{}row[5]) = x1e6
gen-id(text[6]) = x1t7
gen-id(Q{}row[7]) = x1e8
gen-id(text[8]) = x1t9
gen-id(Q{}row[9]) = x1e10
gen-id(#id[10]) = x1e10a0
gen-id(#xml:id[10]) = x1e10a1
gen-id(text[10]) = x1t11
Output using Qt 5.5 or 5.4
I used the pre-build xmlpatterns.exe and called it as xmlpatterns test.xsl input.xml, but its code uses the same libraries you are using:
gen-id(Q{}root[1]) = T756525610
gen-id(#test[2]) = T756525620
gen-id(text[2]) = T756525630
gen-id(processing-instruction[3]) = T756525640
gen-id(text[4]) = T756525650
gen-id(Q{}row[5]) = T756525660
gen-id(text[6]) = T756525670
gen-id(comment[7]) = T756525680
gen-id(text[8]) = T756525690
gen-id(Q{}row[9]) = T7565256100
gen-id(text[10]) = T7565256110
gen-id(text[11]) = T7565256120
gen-id(Q{}row[12]) = T7565256130
gen-id(text[13]) = T7565256140
gen-id(text[14]) = T7565256150
gen-id(Q{}row[15]) = T7565256160
gen-id(#id[16]) = T7565256170
gen-id(#xml:id[16]) = T7565256180
gen-id(text[16]) = T7565256190
gen-id(text[17]) = T7565256200
As this shows, stripping space does not work with Qt, as it considers them text nodes. But as you can also see, the generate-id function works for each and every node, whether they are processing instructions, text nodes, look the same, are empty elements etc. It didn't matter whether:
Using generate-id() vs generate-id(.)
Putting it in xsl:for-each or normal template processing
Using a variable to store the result prior to using
Hiding generate-id() inside another function
All returned the same, valid result.
UPDATE: Workaround
There's a relative expensive, yet workable workaround that you may be able to use, assuming that the generated ID in itself must be unique per document and node, but is not used in another way then for uniqueness (for instance, if used for cross-references, this will work).
<xsl:variable name="doc" select=".//node()" />
<xsl:function name="my:gen-id" as="xs:integer">
<xsl:param name="elem" as="node()" />
<xsl:sequence select="
for $i in 1 to count($doc)
return if($doc[$i] is $elem then $i else ())" />
</xsl:function>
This obviously has a performance hit, but if your documents are not that big and/or you do not call this function too often, it should be ok. You may consider creating a key if the subset for which you need this is defined.
A call to generate-id() returns a generated id of the context node and of course, if the context does not change, you will always get the same value.
I found out a solution for this problem. It seems to be some differences between Qt4 and Qt5 XSLT transformation engine in Linux.
The following code worked fine in Qt4, but not in Qt5. tc_id has always the same value:
<xsl:for-each select="testcase">
<xsl:choose>
<xsl:when test="#result != 'pass'">
<xsl:variable name="tc_id" select="generate-id(.)"/>
<xsl:attribute name="onClick">
ExpandCollapse('<xsl:value-of select="$tc_id"/>');
</xsl:attribute>
<div style="display:none">
<xsl:attribute name="id"><xsl:value-of select="$tc_id"/></xsl:attribute>
</div>
</xsl:when>
<xsl:otherwise>
...
</xsl:otherwise>
</xsl:choose>
</xsl:for-each>
And the following code works fine both in Qt4 and Qt5:
<xsl:for-each select="testcase">
<xsl:choose>
<xsl:when test="#result != 'pass'">
<xsl:attribute name="onClick">
ExpandCollapse('<xsl:value-of select="generate-id(.)"/>');
</xsl:attribute>
<div style="display:none">
<xsl:attribute name="id"><xsl:value-of select="generate-id(.)"/></xsl:attribute>
</div>
</xsl:when>
<xsl:otherwise>
...
</xsl:otherwise>
</xsl:choose>
</xsl:for-each>
It seems there is some problem with declaring the variable.
I have an XSLT like this:
<?xml version="1.0" encoding="UTF-8"?>
<xsl:transform version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xalan="http://xml.apache.org/xalan">
<xsl:variable name="fooDocument" select="document('fooDocument.xml')"/>
<xsl:template match="/">
<xsl:apply-templates select="$fooDocument//*"/>
</xsl:template>
<xsl:template match="nodeInFooDocument">
<xsl:variable name="valueFromSource" select="//someSourceElement"/>
</xsl:template>
</xsl:transform>
In the second template, which matches nodes in the fooDocument.xml which is loaded with document(), I want to access nodes in the XML source the transformation is executed upon. This does not work with //someSourceElement, because apparently, XPath executes this path in the context of fooDocument.
A first workaround that comes to mind is this:
...
<!-- global variable -->
<xsl:variable name="root" select="/"/>
...
<!-- in the template -->
<xsl:variable name="valueFromSource" select="$root//someSourceElement"/>
...
But I cannot use this workaround, because actually, my variable is selected like this:
<xsl:variable name="valueFromSource" select="xalan:evaluate($someXPathString)"/>
$someXPathString is not crafted in the XSLT file, but loaded from fooDocument (and contains an absolute path like the one used above). Still, I need to somehow change the XPath context back to the XML source. A very hacky workaround I found is this:
<xsl:for-each select="$root[1]">
<xsl:variable name="valueFromSource" select="xalan:evaluate($someXPathString)"/>
</xsl:for-each>
The (useless) for-each loop changes the context back to the main XML source, thus the XPath evaluates correctly. But obviously, this is not an acceptable solution.
Is there a way to do this right, or can someone suggest a better workaround?
Even if you think your attempt with a for-each select="$root" to change the context document is not acceptable this is the right approach. So use that, there is no other way.
Have you considered doing all the computation that constructs $someXPathString using a series of global variables?
<xsl:variable name="fooDocument" select="document('fooDocument.xml')"/>
<xsl:variable name="temp1"
.. some computation using fooDocument ..
</xsl:variable>
<xsl:variable name="temp2"
.. some computation using temp1 ..
</xsl:variable>
<xsl:variable name="someXPathString"
.. some computation using temp2 ..
</xsl:variable>
<xsl:variable name="root" select="xalan:evaluate($someXPathString)"/>
I need to be able to store a node set in variable and then perform more filting/sorting on it afterward. All the examples I've seen of this involve either using XSL2 or extensions neither of which are really an option.
I've a list of hotels in my XML doc that can be sorted/filtered and then paged through 5 at a time. I'm finding though I'm repeating alot of the logic as currently I've not found a good way to store node-sets in xsl variable and then use xpath on them for further filtering/sorting.
This is the sort of thing I'm after (excuse the code written of the top of my head so might not be 100%):
<xsl:variable name="hotels" select="/results/hotels[active='true']" />
<xsl:variable name="3_star_or_less" select="/results/hotels[number(rating) <= 3]" />
<xsl:for-each select="3_star_or_less">
<xsl:sort select="rating" />
</xsl:for-each>
Has anyone got an example of how best to do this sort of thing?
Try this example:
<xsl:variable name="hotels" select="/results/hotels[active='true']" />
<xsl:variable name="three_star_or_less"
select="$hotels[number(rating) <= 3]" />
<xsl:for-each select="$three_star_or_less">
<xsl:sort select="rating" />
<xsl:value-of select="rating" />
</xsl:for-each>
There is no problem storing a node-set in a variable in XSLT 1.0, and no extensions are needed. If you just use an XPath expression in select attribute of xsl:variable, you'll end up doing just that.
The problem is only when you want to store the nodes that you yourself had generated in a variable, and even then only if you want to query over them later. The problem here is that nodes you output don't have type "node-set" - instead, they're what is called a "result tree fragment". You can store that to a variable, and you can use that variable to insert the fragment into output (or another variable) later on, but you cannot use XPath to query over it. That's when you need either EXSLT node-set() function (which converts a result tree fragment to a node-set), or XSLT 2.0 (in which there are no result tree fragments, only sequences of nodes, regardless of where they come from).
For your example as given, this doesn't seem to be a problem. Rubens' answer gives the exact syntax.
Another note, if you want to be able to use the variable as part of an XPath statement, you need to select into the variable with <xsl:copy-of select="."/> instead of <xsl:value-of select="."/>
value-of will only take the text of the node and you wont be able to use the node-set function to return anything meaningful.
<xsl:variable name="myStringVar">
<xsl:value-of select="."/>
</xsl:variable>
<!-- This won't work: -->
<Output>
<xsl:value-of select="node-set($myStringVar)/SubNode" />
</Output>
<xsl:variable name="myNodeSetVar">
<xsl:copy-of select="."/>
</xsl:variable>
<!-- This will work: -->
<Output>
<xsl:value-of select="node-set($myNodeSetVar)/SubNode" />
</Output>