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Satoshi Hada IBM Tokyo Research Laboratory mailto:satoshih@jp.ibm.com seth proctor <Seth.Proctor@Sun.COM> Sent by: Seth.Proctor@Sun.COM 2004/05/06 06:24 To xacml@lists.oasis-open.org cc Subject [xacml] XPath/AttributeSelector question Ok. I'm hoping that someone who's more of an XPath hacker than I can help me with this one. The 1.x specification says in 5.32 (Element <AttributeSelector>) that the context node for the given XPath expression is the Request element. As I understand the term "context node" this means not only that the Request element is the root of the XPath query, but that the Request element also provides all namespace information. Is this correct? The reason I ask is because in the conformance tests one of the test cases (IIIF007) has an AttributeSelector with an XPath expression that relies on namespace definitions from the Policy root element. If this is really valid, then I believe (though I may be wrong) that the text in 5.32 is incorrect or incomplete. Can someone help me out here? seth To unsubscribe from this mailing list (and be removed from the roster of the OASIS TC), go to http://www.oasis-open.org/apps/org/workgroup/xacml/members/leave_workgroup.php . --=_alternative 000592FA49256E8D_= Content-Type: text/html; charset="US-ASCII" <br><font size=2><tt>>> the term "context node" this means not only that the <br> >> Request element is the root of the XPath query, but that the Request <br> >> element also provides all namespace information. Is this correct?</tt></font> <br> <br><font size=2 face="sans-serif">I don't think the term has some implication about how or where we need to provide namespace-related information, </font> <br><font size=2 face="sans-serif">in particular, where we specify the required PREFIX-to-URI mapping (But I may be wrong).</font> <br> <br><font size=2 face="sans-serif">Please see the mails with the title "Test cases for Attribute Selector" for related discussion.</font> <br><font size=2 face="sans-serif">http://lists.oasis-open.org/archives/xacml-comment/200303/maillist.html</font> <br> <br><font size=2 face="sans-serif">I have two comments on this issue.</font> <br> <br><font size=2 face="sans-serif">(A)</font> <br><font size=2 face="sans-serif">Personally, I feel the namespace information (xmlns attributes) required to resolve an XPath expression </font> <br><font size=2 face="sans-serif">should be provided in policies but not in request contexts since attribute selectors (and XPath expressions) are specified in policies </font> <br><font size=2 face="sans-serif">but not in request contexts. If a policy specifies an XPath expression (e.g. /md:record) in an attribute selector but </font> <br><font size=2 face="sans-serif">provides no namespace information (no "xmlns:md" attribute), then I think the policy is ambiguous by itself.</font> <br> <br><font size=2 face="sans-serif">(B)</font> <br><font size=2 face="sans-serif">There is no reason why we must use the same namespace prefix to represent a namespace URI</font> <br><font size=2 face="sans-serif">in policies and request contexts.</font> <br><font size=2 face="sans-serif">Take for example the IIF007 testcase. The policy and request use the same prefix "md".</font> <br><font size=2 face="sans-serif">However, I believe that it should work even if the policy and reqeust use two different prefixes:</font> <br><font size=2 face="sans-serif">1) In IIIF007Policy.xml, replace the prefix "md" with a different one (e.g. "medical"), but</font> <br><font size=2 face="sans-serif">2) In IIIF007Request.xml, leave the prefix "md" as it is.</font> <br><font size=2 face="sans-serif">Note that the two prefixes still represent the same URI.</font> <br><font size=2 face="sans-serif">In this case, information required to resolve the "medical" prefix should be provided in IIIF007Policy.xml</font> <br><font size=2 face="sans-serif">and information required to resolve the "md" prefix should be provided in IIIF007Request.xml</font> <br> <br><font size=2 face="sans-serif">From my perspective, IIIF002Request.xml does not need to have the "xmlns:md" attribute since </font> <br><font size=2 face="sans-serif">it does not use the prefix "md" in it (even though IIIF002Policy.xml uses it).</font> <br> <br><font size=2 face="sans-serif">Satoshi Hada<br> IBM Tokyo Research Laboratory <br> mailto:satoshih@jp.ibm.com</font> <br> <br> <br> <table width=100%> <tr valign=top> <td width=40%><font size=1 face="sans-serif"><b>seth proctor <Seth.Proctor@Sun.COM></b> </font> <br><font size=1 face="sans-serif">Sent by: Seth.Proctor@Sun.COM</font> <p><font size=1 face="sans-serif">2004/05/06 06:24</font> <td width=59%> <table width=100%> <tr> <td> <div align=right><font size=1 face="sans-serif">To</font></div> <td valign=top><font size=1 face="sans-serif">xacml@lists.oasis-open.org</font> <tr> <td> <div align=right><font size=1 face="sans-serif">cc</font></div> <td valign=top> <tr> <td> <div align=right><font size=1 face="sans-serif">Subject</font></div> <td valign=top><font size=1 face="sans-serif">[xacml] XPath/AttributeSelector question</font></table> <br> <table> <tr valign=top> <td> <td></table> <br></table> <br> <br> <br><font size=2><tt><br> Ok. I'm hoping that someone who's more of an XPath hacker than I can <br> help me with this one.<br> <br> The 1.x specification says in 5.32 (Element <AttributeSelector>) that <br> the context node for the given XPath expression is the Request element. <br> As I understand the term "context node" this means not only that the <br> Request element is the root of the XPath query, but that the Request <br> element also provides all namespace information. Is this correct?<br> <br> The reason I ask is because in the conformance tests one of the test <br> cases (IIIF007) has an AttributeSelector with an XPath expression that <br> relies on namespace definitions from the Policy root element. If this is <br> really valid, then I believe (though I may be wrong) that the text in <br> 5.32 is incorrect or incomplete.<br> <br> Can someone help me out here?<br> <br> <br> seth<br> <br> <br> To unsubscribe from this mailing list (and be removed from the roster of the OASIS TC), go to http://www.oasis-open.org/apps/org/workgroup/xacml/members/leave_workgroup.php.<br> <br> </tt></font> <br> --=_alternative 000592FA49256E8D_=--
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