I'm wondering if there is a way to do the following with one xpath expression:
I have an XML doc similar to this but with many 'results',
<result>
<id>1</id>
<name>joe</name>
</result>
<result>
<id>2</id>
<name>jim</name>
</result>
I'm passing a variable into a C# utility along with the xml, and want to return the name where the id = the variable.
I could loop through the xml until reach what I'm after but if there's a handy xpath way to do it I'm listening...
thanks
Assuming you have a root element in there like "results" that XPath can validate, and that you don't have any other nodes named "result"...
//result[id=1]/name
Or you could get the text outright, instead of it being returned in a node
//result[id=1]/name/text()
And if you want to make sure that there's only one result, you could surround it with parens and put a [1] after
(//result[id=1]/name/text())[1]
I would also recommend testing with one of the xpath test sites out there like this one, but beware that different xpath/xml parsers sometimes behave differently.
Related
I am trying to convert nodes that have a namespace declaration over to use a prefix instead. My first stab at it was to just use xslt to transform the xml, but I started looking at doing it with the XmlDocument class and using the SelectNodes() method. The issue I am seeing is when I try to select nodes that have a namespace, it selects that node AND its children. I assume this is because it is selecting the node which contains children.
<foo xmlns="some url">
<child>child</child>
</foo>
XmlDocument xdoc = new XmlDocument();
xdoc.LoadXml(xmlstring);
var query = xdoc.SelectNodes("//*[namespace-uri()='some url']");
the query variable will return <foo> and <child> nodes, so when I loop through the nodes and change it to use the prefix, I get the following result.
<prefix:foo>
<prefix:child></prefix:child>
</prefix:foo>
Is there a way to just return just the <foo> node in this case? Is it better to also use xslt to transform it?
I didnt think you could change a namespace or prefix when using XDocument and XElement, so thats why I used XmlDocument.
Update
The result id want would be the prefix only on the node where the declaration was. This is valid xml correct or does the prefix need to be on the children as well to be valid?
<prefix:foo>
<child>child</child>
</prefix:foo>
In the XDM data model used by XPath and XSLT, there is no distinction between
<foo xmlns="some url">
<child>child</child>
</foo>
and
<foo xmlns="some url">
<child xmlns="some url">child</child>
</foo>
Logically the namespace is present on both element nodes, and its omission from the child in the lexical serialization is treated as a convenient abbreviation.
So yes, if you search for things having this namespace, you will get both elements.
Now, what are your requirements? I'm not convinced you fully understand them yourself, because the desired output you have shown is not actually well-formed (the namespace prefix is not declared). In your input, the two elements are in the same namespace; in the output, you seem to want them to be in different namespaces. If you want to process them differently, then you're going to have to use something other than the namespace to discriminate between them.
Remember that in XDM, it's the name of the node that matters, not the namespace declarations or prefixes; those are just ornamental. The name of the node is the combination of its local name and its namespace URI. You've described your requirement in terms of prefixes, but it's namespaces that actually matter.
I'm using XDocument and I need to parse my XML file to retrieve all attribute with the same name event if its node's name is different from the other.
For example, for this XML :
<document>
<person name='jame'/>
<animals>
<dog name='robert'/>
</animals>
</document>
I want to retrieve all attributes named 'name'.
Can I do that with one request XPath or do I need to parse every node to find thos attributes ?
Thanks for your help !
The XPath expression
//#name
will select all attributes called name, regardless of where they appear.
By the way, 'parsing' is something that happens to the XML document before XPath ever enters the picture. So when you say "do I need to parse every node", I think this isn't really what you mean. The entire document is typically already parsed before you run an XPath query. However, I'm not sure what you do mean instead of 'parse'. Probably something like "do I need to visit every element" to find those attributes? In which case the answer is no, unless in some vague implementation-dependent sense that doesn't make any difference to you.
I am working on a biztalk project and I need to copy (filtered) content from 1 xml to another.
I have to do this with xpath, I can't use xsl transformation.
So my xpath to get the content from the source xml file is this:
//*[not(ancestor-or-self::IN1_Insurance)]|//IN1_Insurance[2]/descendant-or-self::*
Now this returns an xmlNodelist. Is it possible to return a string with all the nodes in it like:
"<root><node>text</node></root>"
If I put string() before my xpath it returns the values, but I want the whole xml in a string (with nodes..), so I could load that string in another xmldocument. I think this is the best method for my problem.
I know I can loop over the xmlnodelist and append the nodes to the new xmldocument, but it's a bit tricky to loop in a biztalk orchestration and I want to avoid this.
The code I can use is C#.
I've tried to just assign the nodelist to the xmldocument, but this throws a cast error (obvious..).
The way I see it is that I have 2 solutions:
assign the nodelist to the xmldocument without a loop (not possible i think in C#)
somehow convert the nodelist to string and load this in the xmldocument
load the xpath directly in the new xmldocument (don't know if this is possible since it returns a nodelist)
Thanks for your help
edit:
sample input:
<root>
<Patient>
<PatientId></PatientId>
<name></name>
</Patient>
<insurance>
<id>1</id>
<billing></billing>
</insurance
<insurance>
<id>2</id>
<billing></billing>
</insurance>
<insurance>
<id>3</id>
<billing></billing>
</insurance>
</root>
Now I want to copy this sample to another xmldocument, but without insurance node 2 and 3 (this is dynamically, so it could be unsurance node 1 and 2 to delete, or 1 and 3...)
So this has to be the output:
<root>
<Patient>
<PatientId></PatientId>
<name></name>
</Patient>
<insurance>
<id>1</id>
<billing></billing>
</insurance>
</root>
What I am doing now is use the xpath to get the nodes I want. Then I want to assign the result to the new xmldocument, but this is not possible since I get the castException
string xpath = "//*[not(ancestor-or-self::IN1_Insurance)]|//IN1_Insurance[2]/descendant-or-self::*";
xmlDoc = new System.Xml.XmlDocument();
xmlDoc = xpath(sourceXml, strXpath); <= cast error (cannot cast xmlnodelist to xmldocuemnt)
I know the syntax is a bit strange, but it is biztalk c# code..
The most straightforward solution would indeed be to "loop over the xmlnodelist and append (import) the nodes to the new xmldocument", but since you can't loop, what other basic things can/can't you do?
To serialize the nodelist, you could try using XmlNodeList.toString(). If that worked, you'd get a strange beast, because it could be duplicating parts of the XML document several times over. Especially since you're explicitly including ancestors and descendants directly in the nodelist. It would not be something that you could parse back in and have a result that resembled the nodelist you started with.
In other words, it would be best to loop over the XmlNodeList and import the nodes to the new XmlDocument.
But even so, I would be really surprised if you wanted to put all these ancestor and descendant nodes:
//*[not(ancestor-or-self::IN1_Insurance)]|//IN1_Insurance[2]/descendant-or-self::
directly into the new XML document. If you post some sample input and the desired output, we can probably help determine if that's the case.
Update:
I see what you're trying to do: copy an XML document, omitting all <insurance> elements (and their descendants) except the one you want.
This can be done without a loop if the output is as simple as your sample output: only one <Patient> and one <insurance> element, with their descendants, under one top-level element.
Something like (I can't test this as I don't have a biztalk server):
string xpathPatient = "/*/Patient";
string xpathInsuran = "/*/insurance[id = " + insId + "]"; // insId is a parameter
xmlDoc = new System.Xml.XmlDocument();
xmlPatient = xpath(sourceXml, xpathPatient);
xmlInsuran = xpath(sourceXml, xpathInsuran);
XmlElement rootNode = xmlDoc.CreateElement("root");
xmlDoc.AppendChild(rootNode);
//**Update: use [0] to get an XmlNode from the returned XmlNodeList (presumably)
rootNode.AppendChild(xmlDoc.ImportNode(xmlPatient[0], true));
rootNode.AppendChild(xmlDoc.ImportNode(xmlInsuran[0], true));
I confess though, I'm curious why you can't use XSLT. You're approaching tasks that would be more easily done in XSLT than in XPath + C# XmlDocument.
Update: since the xpath() function probably returns an XmlNodeList rather than an XmlNode, I added [0] to the first argument to ImportNode() above. Thanks to #Martin Honnen for alerting me to that.
XPath is a query language (only) for XML documents.
It operates on an abstract model -- the XML INFOSET, and cannot either modify the structure of the XML document(s) it operates on or serialize the INFOSET information items back to XML.
Therefore, the only way to achieve such serialization is to use the language that is hosting XPath.
Apart from this, there are obvious problems with yout question, for example these is no element named IN1_Insurance in the provided XML document -- therefore the XPath expression provided:
//*[not(ancestor-or-self::IN1_Insurance)]|//IN1_Insurance[2]/descendant-or-self::*
selects all elements in the document.
Note:
The described task is elementary to fulfil using XSLT.
Finally: If you are allowed to use C# then you can use the XslCompiledTransform (or XslTransform) class. Use its Transform() method to carry out the following transformation against the XML document:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:template match="node()|#*">
<xsl:copy>
<xsl:apply-templates select="node()|#*"/>
</xsl:copy>
</xsl:template>
<xsl:template match="insurance[not(id=1)]"/>
</xsl:stylesheet>
This produces exactly the wanted result:
<root>
<Patient>
<PatientId></PatientId>
<name></name>
</Patient>
<insurance>
<id>1</id>
<billing></billing>
</insurance>
</root>
I need to find an inner text of an element inside an XmlDocument and return it's Xpath.
for example, searching for "ThisText" inside :
<xml>
<xml2>ThisText</xml2>
</xml>
should return the Xpath of xml2
what's the most efficient way of doing this in c#?
What do you think the "xpath" of an element is? An xpath is a querying language in order to find a node/nodes, not to describe where a node is.
You can use an xpath to find the element in question. e.g.
xmlDocument.SelectNodes("//*[contains(text(), 'ThisText')]");
Then you can loop through the returned nodes and look at their name / parent, etc.
I'm writing some code that handles logging xml data and I would like to be able to replace the content of certain elements (eg passwords) in the document. I'd rather not serialize and parse the document as my code will be handling a variety of schemas.
Sample input documents:
doc #1:
<user>
<userid>jsmith</userid>
<password>myPword</password>
</user>
doc #2:
<secinfo>
<ns:username>jsmith</ns:username>
<ns:password>myPword</ns:password>
</secinfo>
What I'd like my output to be:
output doc #1:
<user>
<userid>jsmith</userid>
<password>XXXXX</password>
</user>
output doc #2:
<secinfo>
<ns:username>jsmith</ns:username>
<ns:password>XXXXX</ns:password>
</secinfo>
Since the documents I'll be processing could have a variety of schemas, I was hoping to come up with a nice generic regular expression solution that could find elements with password in them and mask the content accordingly.
Can I solve this using regular expressions and C# or is there a more efficient way?
This problem is best solved with XSLT:
<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="#* | node()">
<xsl:copy>
<xsl:apply-templates select="#* | node()"/>
</xsl:copy>
</xsl:template>
<xsl:template match="//password">
<xsl:copy>
<xsl:text>XXXXX</xsl:text>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>
This will work for both inputs as long as you handle the namespaces properly.
Edit : Clarification of what I mean by "handle namespaces properly"
Make sure your source document that has the ns name prefix has as namespace defined for the document like so:
<?xml version="1.0" encoding="utf-8"?>
<secinfo xmlns:ns="urn:foo">
<ns:username>jsmith</ns:username>
<ns:password>XXXXX</ns:password>
</secinfo>
I'd say you're better off parsing the content with a .NET XmlDocument object and finding password elements using XPath, then changing their innerXML properties. It has the advantage of being more correct (since XML isn't regular in the first place), and it's conceptually easy to understand.
From experience with systems that try to parse and/or modify XML without proper parsers, let me say: DON'T DO IT. Use an XML parser (There are other answers here that have ways to do that quickly and easily).
Using non-xml methods to parse and/or modify an XML stream will ALWAYS lead you to pain at some point in the future. I know, because I have felt that pain.
I know that it seems like it would be quicker-at-runtime/simpler-to-code/easier-to-understand/whatever if you use the regex solution. But you're just going to make someone's life miserable later.
You can use regular expressions if you know enough about what you are trying to match. For example if you are looking for any tag that has the word "password" in it with no inner tags this regex expression would work:
(<([^>]*?password[^>]*?)>)([^<]*?)(<\/\2>)
You could use the same C# replace statement in zowat's answer as well but for the replace string you would want to use "$1XXXXX$4" instead.
Regex is the wrong approach for this, I've seen it go so badly wrong when you least expect it.
XDocument is way more fun anyway:
XDocument doc = XDocument.Parse(#"
<user>
<userid>jsmith</userid>
<password>password</password>
</user>");
doc.Element("user").Element("password").Value = "XXXX";
// Temp namespace just for the purposes of the example -
XDocument doc2 = XDocument.Parse(#"
<secinfo xmlns:ns='http://tempuru.org/users'>
<ns:userid>jsmith</ns:userid>
<ns:password>password</ns:password>
</secinfo>");
doc2.Element("secinfo").Element("{http://tempuru.org/users}password").Value = "XXXXX";
Here is what I came up with when I went with XMLDocument, it may not be as slick as XSLT, but should be generic enough to handle a variety of documents:
//input is a String with some valid XML
XmlDocument doc = new XmlDocument();
doc.LoadXml(input);
XmlNodeList nodeList = doc.SelectNodes("//*");
foreach (XmlNode node in nodeList)
{
if (node.Name.ToUpper().Contains("PASSWORD"))
{
node.InnerText = "XXXX";
}
else if (node.Attributes.Count > 0)
{
foreach (XmlAttribute a in node.Attributes)
{
if (a.LocalName.ToUpper().Contains("PASSWORD"))
{
a.InnerText = "XXXXX";
}
}
}
}
The main reason that XSLT exist is to be able to transform XML-structures, this means that an XSLT is a type of stylesheet that can be used to alter the order of elements och change content of elements. Therefore this is a typical situation where it´s highly recommended to use XSLT instead of parsing as Andrew Hare said in a previous post.