I am new to XPath. Please help me to get category values for each report using XPathExpression in java.
<reports>
<report>
<allocation>
<Category>
<c_name>Category 1</c_name>
<c_value>5588.79776</c_value>
<c_percent>17.84</c_percent>
<fund_details />
</Category>
<Category>
<c_name>Category 2</c_name>
<c_value>7362.15208</c_value>
<c_percent>23.50</c_percent>
<fund_details>
<fund>
<f_value>3511.66</f_value>
</fund>
</fund_details>
</Category>
</allocation>
</report>
<report>
<allocation>
<Category>
<c_name>Category 1</c_name>
<c_value>12</c_value>
<c_percent>16</c_percent>
<fund_details />
</Category>
<Category>
<c_name>Category 2</c_name>
<c_value>74</c_value>
<c_percent>02</c_percent>
</Category>
</allocation>
</report>
</reports>
expected output:
List of c_name,c_value,c_percent from category node for each report node.
You can download an xpath plug in on your browser. This way you only have to right click the element you want to get and view its xpath . I don't know which browser you usually use but I use firefox's firebug plugin which is ideal. I just inspect using it right click the element and copy its xpath to my code;
Related
I can't figure out how to write a rule that would solve this requirement :
Let's assume I have this request :
<Request>
<Attributes Category="urn:oasis:names:tc:xacml:1.0:subject-category:access-subject">
<Content>
<Categories>
<Category name="cat1">
<CategoryValue>A</CategoryValue>
<CategoryValue>B</CategoryValue>
<CategoryValue>C</CategoryValue>
</Category>
<Category name="cat2">
<CategoryValue>B</CategoryValue>
<CategoryValue>E</CategoryValue>
<CategoryValue>F</CategoryValue>
</Category>
</Categories>
</Content>
</Attributes>
<Attributes Category="urn:oasis:names:tc:xacml:3.0:attribute-category:resource">
<Content>
<Categories>
<Category name="cat1">
<CategoryValue>A</CategoryValue>
</Category>
<Category name="cat2">
<CategoryValue>A</CategoryValue>
<CategoryValue>E</CategoryValue>
<CategoryValue>F</CategoryValue>
<CategoryValue>G</CategoryValue>
</Category>
</Categories>
</Content>
</Attributes>
</Request>
I want to write a policy that contains a rule with a Permit effect when for each of the Category elements of the resource, the subject has a Category with the same #name and if both of these Category elements has at least one common CategoryValue.
In this Example above :
Resource has "cat1" with "A" - Subject has "cat1" with one value that is A : Permit
Resource has "cat2" with "A", "E", "F", "G" - Subject has "cat2" with value E (or F) : Permit
Final result of the rule : Permit
My question is not on which functionId I should use, but how can I combine these conditions so that the rule behaves the way I described ? How to compare the GenericValue elements of nodes that has the same #name ?
I think I will have to use the string-at-least-one-member-of function between the values of the subject and resource "cat1", then between the subject and resource "cat2", but the real difficulty is that the PDP has no idea of the #name of the Category elements, so I can't hardcode it directly in the rule and I don't know how to select them in particular to perform the check.
Any idea on this ?
First of all, your request is invalid. You are missing some elements e.g.
ReturnPolicyIdList="true"
CombinedDecision="true"
Secondly, I would recommend you do not use XPath in XACML. It makes your policies hard to write (hence your question), hard to maintain, and hard to read (audit). It defeats the purpose of XACML in a way. Let the PEP do the heavy XML processing and send in attributes with attribute values rather than XML content.
In addition, you cannot control the iteration over the different elements / attribute values in the XML in XACML. I can implement your use case with a specific #name value but I cannot manage to do it over an array of values.
Assuming a single value, you would have to implement a condition as follows:
<xacml3:Rule RuleId="axiomatics-example-xacml30" Effect="Permit" xmlns:xacml3="urn:oasis:names:tc:xacml:3.0:core:schema:wd-17">
<xacml3:Target/>
<xacml3:Condition >
<xacml3:Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:string-at-least-one-member-of">
<xacml3:AttributeSelector Path="/Categories/Category[#name='cat1']/CategoryValue/text()" DataType="http://www.w3.org/2001/XMLSchema#string" MustBePresent="false" Category="urn:oasis:names:tc:xacml:1.0:subject-category:access-subject"/>
<xacml3:AttributeSelector Path="/Categories/Category[#name='cat1']/CategoryValue/text()" DataType="http://www.w3.org/2001/XMLSchema#string" MustBePresent="false" Category="urn:oasis:names:tc:xacml:3.0:attribute-category:resource"/>
</xacml3:Apply>
</xacml3:Condition>
</xacml3:Rule>
But you cannot really iterate over the different values
<Item id="item0">
<Links>
<FirstLink id="link1" target="one"/>
<SecondLink id="link2" target="two"/>
</Links>
<Data>
<String>content</String>
</Data>
</Item>
<Item id="item1">
<Links>
<FirstLink id="link1" target="two"/>
<SecondLink id="link2" target="two"/>
</Links>
<Data>
<String>content</String>
</Data>
</Item>
I have created a Nokogiri-NodeSet with this structure, i.e. a list of items with links and data children.
How can I filter any items that don't match a certain value in the 'target'-attribute of <FirstLink>?
Actually, what I want in the end is to extract the <Data><String>-Content of every <Item> that matches a certain value in it's <FirstLink> "Target"-Attribute.
I've tried several approaches already but I'm at a loss as to how to identify an element by an attribute of it's grandchild, then extracting the content of this grandchild's parent's sibling, X(.
We can build up an XPath expression to do this. Assuming we are starting from the whole XML document, rather than the node-set you already have, something like
//Item
will select all <Item> elements (I’m guessing you already have something like that to get this node-set).
Next, to select only those <Item> elements which have <Links><FirstLink> where FirstLink has a target attribute value of one:
//Item[Links/FirstLink[#target='one']]
and finally to select the Data/String children of those nodes:
//Item[Links/FirstLink[#target='one']]/Data/String
So with Nokogiri you could use something like this (where doc is your parsed document):
doc.xpath("//Item[Links/FirstLink[#target='one']]/Data/String")
or if you want to use the node-set you already have you can use a relative expression:
nodeset.xpath("self::Item[Links/FirstLink[#target='one']]/Data/String")
I completely didn't understand what your goal is. But using a guess, I am trying to show you, how to proceed in this case :
require 'nokogiri'
doc = Nokogiri::XML <<-xml
<Item id="item0">
<Links>
<FirstLink id="link1" target="one"/>
<SecondLink id="link2" target="two"/>
</Links>
<Data>
<String>content1</String>
</Data>
</Item>
<Item id="item1">
<Links>
<FirstLink id="link1" target="two"/>
<SecondLink id="link2" target="two"/>
</Links>
<Data>
<String>content2</String>
</Data>
</Item>
xml
#xpath method with the expression "//Item", will select all the Item nodes. Then those Item nodes will be passed to the #reject method to select only those nodes, that has a node called Links having the target attribute value is "one". If any of the links, either FirstLink or SecondLink has the target attribute value "one", for that nodes grandparent node Item will be selected.
node.at("//Links/FirstLink")['target'] will give you the string say "one" which is a value of target attribute of the node, FirstLink of first Item nodes , then "two" from the second Item node. The part ['any vaue'] in node.at("//Links/FirstLink")['target']['any vaue'] is a call to the String#[] method.
Remember below approach will give you the flexibility of the use regular expression too.
nodeset = doc.xpath("//Item").reject do |node|
node.at("//Links/FirstLink")['target']['any vaue']
end
Now nodeset contains only the required Item nodes. Now I use #map, passing each item node inside it to collect the content of the String node. Then #at method with an expression //Data/String, will select the String node. Then #text, will give you the content of each String node.
nodeset.map { |n| n.at('//Data/String').text } # => ["content1"]
Using LINQ to XML, how do I get a collection of all elements that have a named child element.
for example;
<root>
<Garage>
<Car id="001">
<Price PaymentType="Cash">$100</Price>
</Car>
<Car id="002">
<Price PaymentType="Cash">$200</Price>
</Car>
<Car id="003">
</Car>
</Garage>
</root>
this will return 2 Car elements (#1 and #2) as they have the Price element. It won't return Car #3, as it doesn't have a price element.
thanks as always
Assuming you have an XDocument object named doc with your example xml loaded into it. You could try something like this.
IEnumerable<XElement> elements = doc.Descendants("Garage").Elements().Where(e => e.Elements().Any());
I'm getting a SOAP response that looks like this:
<Activity>
<Id>A</Id>
<Subject>foo</Subject>
<Activity>Task</Activity>
</Activity>
<Activity>
<Id>B</Id>
<Subject>bar</Subject>
<Activity>Appointment</Activity>
</Activity>
<Activity>
<Id>C</Id>
<Subject>snafu</Subject>
<Activity>Task</Activity>
</Activity>
In Coldfusion, I was trying to parse out the Activity nodes with this:
<cfset arrMainNodes = XmlSearch(soapResponse, "//*[name()='Activity']") />
The problem is, instead if getting an array with three elements, I get an array with six: 3 of the parent, and 3 of the children.
I can't for the life of me figure out the XPath statement the will find siblings only, and not children.
Please Help.
Use:
//*[name()='Activity' and not(ancestor::*[name()='Activity' ])]
This selects all elements in the document, whose name is "Activity" and that do not have an ancestor with name "Activity".
The XPath bookstore/book[1] selects the first book node under bookstore.
How can I select the first node that matches a more complicated condition, e.g. the first node that matches /bookstore/book[#location='US']
Use:
(/bookstore/book[#location='US'])[1]
This will first get the book elements with the location attribute equal to 'US'. Then it will select the first node from that set. Note the use of parentheses, which are required by some implementations.
Note, this is not the same as /bookstore/book[1][#location='US'] unless the first element also happens to have that location attribute.
/bookstore/book[#location='US'][1] works only with simple structure.
Add a bit more structure and things break.
With-
<bookstore>
<category>
<book location="US">A1</book>
<book location="FIN">A2</book>
</category>
<category>
<book location="FIN">B1</book>
<book location="US">B2</book>
</category>
</bookstore>
/bookstore/category/book[#location='US'][1] yields
<book location="US">A1</book>
<book location="US">B2</book>
not "the first node that matches a more complicated condition". /bookstore/category/book[#location='US'][2] returns nothing.
With parentheses you can get the result the original question was for:
(/bookstore/category/book[#location='US'])[1] gives
<book location="US">A1</book>
and (/bookstore/category/book[#location='US'])[2] works as expected.
As an explanation to Jonathan Fingland's answer:
multiple conditions in the same predicate ([position()=1 and #location='US']) must be true as a whole
multiple conditions in consecutive predicates ([position()=1][#location='US']) must be true one after another
this implies that [position()=1][#location='US'] != [#location='US'][position()=1]
while [position()=1 and #location='US'] == [#location='US' and position()=1]
hint: a lone [position()=1] can be abbreviated to [1]
You can build complex expressions in predicates with the Boolean operators "and" and "or", and with the Boolean XPath functions not(), true() and false(). Plus you can wrap sub-expressions in parentheses.
The easiest way to find first english book node (in the whole document), taking under consideration more complicated structered xml file, like:
<bookstore>
<category>
<book location="US">A1</book>
<book location="FIN">A2</book>
</category>
<category>
<book location="FIN">B1</book>
<book location="US">B2</book>
</category>
</bookstore>
is xpath expression:
/descendant::book[#location='US'][1]
<bookstore>
<book location="US">A1</book>
<category>
<book location="US">B1</book>
<book location="FIN">B2</book>
</category>
<section>
<book location="FIN">C1</book>
<book location="US">C2</book>
</section>
</bookstore>
So Given the above; you can select the first book with
(//book[#location='US'])[1]
And this will find the first one anywhere that has a location US. [A1]
//book[#location='US']
Would return the node set with all books with location US. [A1,B1,C2]
(//category/book[#location='US'])[1]
Would return the first book location US that exists in a category anywhere in the document. [B1]
(/bookstore//book[#location='US'])[1]
will return the first book with location US that exists anywhere under the root element bookstore; making the /bookstore part redundant really. [A1]
In direct answer:
/bookstore/book[#location='US'][1]
Will return you the first node for book element with location US that is under bookstore [A1]
Incidentally if you wanted, in this example to find the first US book that was not a direct child of bookstore:
(/bookstore/*//book[#location='US'])[1]
Use the index to get desired node if xpath is complicated or more than one node present with same xpath.
Ex :
(//bookstore[#location = 'US'])[index]
You can give the number which node you want.
if namespace is provided on the given xml, its better to use this.
(/*[local-name() ='bookstore']/*[local-name()='book'][#location='US'])[1]
for ex.
<input b="demo">
And
(input[#b='demo'])[1]
With help of an online xpath tester I'm writing this answer...
For this:
<table id="t2"><tbody>
<tr><td>123</td><td>other</td></tr>
<tr><td>foo</td><td>columns</td></tr>
<tr><td>bar</td><td>are</td></tr>
<tr><td>xyz</td><td>ignored</td></tr>
</tbody></table>
the following xpath:
id("t2") / tbody / tr / td[1]
outputs:
123
foo
bar
xyz
Since 1 means select all td elements which are the first child of their own direct parent.
But the following xpath:
(id("t2") / tbody / tr / td)[1]
outputs:
123