enketo-validate

Enketo Validate

Validate ODK XForms using Enketo's form engine

This app can be used:

1. via the command-line, e.g. in a non-javascript form builder such as pyxform.
2. as a nodeJS module to be used in your own javascript application

Live demo web application (meant for testing purposes only) that uses Enketo Validate (and ODK Validate) as a module: validate.enketo.org (source code)

Via Command-line

Command-line Install

1. install nodeJS 6+
2. clone repo
3. npm install --production

Command-line Use

$ ./validate ~/myform.xml

Command-line Help

$ ./validate --help

As NodeJS module

Module installation

npm install enketo-validate --save

Module Use

const validator = require('enketo-validate');

// read the xform as string

let result = validator.validate( xformStr );

// The result has the following format:
// {
//      warnings: [ 'a warning', 'another warning'],
//      errors: ['an error', 'another error']
// }
// if errors.length is 0, the form passed validation

How it works

In it's current iteration, the validator does the following:

• It checks whether the XForm is a valid XML document.
• It performs some basic ODK XForm structure checks.
• It checks if each bind nodeset exists in the primary instance.
• It checks for each <bind> whether the relevant, constraint, calculate, and required expressions are supported and valid* XPath.

* Note, that /path/to/nonexisting/node is perfectly valid XPath.

In the future, some ideas to extend validation further are:

• Check itemsets.
• Check more thoroughly whether XForms syntax is valid using an XML Schema.
• Check whether all itext elements referred to anywhere exist in model.

Using a custom XPath Evaluator

The following example shows how to swap Enketo's XPath evaluator with OpenClinica's custom XPath evaluator in command-line mode:

1. Instead of using npm install --production do npm install which which will also install devDepencies.
2. Run npm run oc-build. This will replace the bundle file in the /build folder.

Funding

The development of this application was funded by OpenClinica.

License

See the license document for this application's license.

Change log

See change log