validate

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Module

The validate accessor is exported by the urn:org:ten60:netkernel:ext:sys module. Import this module to gain access to the accessor.

Syntax

URI

active:validate

Argument	Rules	Description
operand	Mandatory	resource to validate
operator	Mandatory	specification on how to validate

Example Usage

DPML

<instr>
  <type>validate</type>
  <operand>var:doc</operand>
  <operator>validationRules.xml</operator>
  <target>var:resultDoc</target>
</instr>

NetKernel Foundation API

req=context.createSubRequest("active:validate");
req.addArgument("operand", [resource representation, aspect, or URI] );
req.addArgument("operator", [resource representation, aspect, or URI] );
result=context.issueSubRequest(req);

Purpose

Performs a set of preset validations on an XHTML document which is part of a UI.

Operator Specification

The operator contains a list of validatations to perform on the operand document. The list is in the form of an XML document with a root element of validator and one of more validation elements which represent the validations to perform. The validation element contains the following elements:

base an xpath expression which will resolve to zero or more paths within the document. This path will define the base path from which the expr and set operations work relative to.
expr an xpath expression which defines the value, relative to base, which contains the value to be validated.
test the contains a string constant that defines the type of validation to perform:
- non-null the field must not be empty
- uri the field must be a well formed URI
- version the field must be a well formed version n1.n2.n3.... where n is a positive integer
- path-dir the field must a heirarchical URI's absolute path to a directory. (i.e. /a/b/)
- absolute-dir the field must be an platform specific absolute filesystem path to a directory.
- duplicate-module the field must be a valid module URN which is not a duplicate of anything already installed
- positive-integer the field must be a positive integer
set one or more set elements may be specified. They define updates to the document to be performed when validation fails:
- xpath attribute the path relative to base (attribute or element) which will have it's text set
- appendDetail attribute if present will append an autogenerated descriptive message describing the problem
- element text the text value to set

This example shows an XHTML input field in a table is being validated to be a URI. If it isn't then error text is placed into the following column and the wrapping row is highlighted by specifying a CSS class.

<validator>
  <validation>
    <base>//input[@name="destination"]</base>
    <expr>@value</expr>
    <test>uri</test>
    <set appendDetail="" xpath="../../td[2]">Malformed: </set>
    <set xpath="../../@class">error</set>
  </validation>
</validator>