w3c-xml-validator

A Node.js library for programmatically confirming whether a given XML document is both well-formed and valid according to the specified DTD.

This project adheres to the standard coding style (click below for more information):

Why?

I was frustrated by the lack of programmatic options for validating XML with JavaScript...in particular, for validating against a public DTD. I realize that there may not be a big need for this across the Node.js community as a whole, but nonetheless it is something I required, so I built this.

W3C

This library relies on the online validator provided by W3C. Please consider donating to the W3C if you find this library useful, because without their tools, this one wouldn't exist. Click on the logo below:

Programmatic Use

This module exports a function that accepts a single value: the XML to be validated. The XML must contain a !DOCTYPE element with an publicly-accessible DTD. The return value is a Promise that will be fulfilled or rejected with the values described below.

Example:

const validate = require('w3c-xml-validator')
const xml = '<?xml version="1.0" encoding="utf-8"?>...'

validate(xml)
    .then(function (response) {
        // the response will contain a basic is/is not valid flag, plus warnings and errors (if present)
    })
    .catch(function (err) {
        // the promise may be rejected for any of the reasons listed below
    })

Fulfillment

When the promise is fulfilled, the returned value will be a plain object with the following properties:

| Key | Data type | Notes | |-----|-----------|-------| | doctype | {String} | The DTD that the validator used. | | isValid | {Boolean} | A simple yes/no based on the results from the W3C validation tool. | | warnings | {Array} of {String} | This is a list of the entries under "Notes and Potential Issues". Each value is the entry title, not the verbose description. | | errors | {Array} of {String} | This is a list of the entries under "Validation Output: # Error(s)". Each value is the entry title that appears in bold, not the verbose description. |

isValid will have the same value as (errors.length === 0). warnings may have entries, even if the validation is successful.

Rejection

The promise may be rejected for any of the following reasons:

• The input parameter is undefined, null, or an empty string.
• The W3C web site is not reachable.
• The W3C web site is not functioning (for example, returns a 5xx HTTP status code).
• The code in this library has a bug that causes the W3C web site to return a 3xx or 4xx HTTP status code.

Check the message property of the error object to find out more information about the source of the problem. If you feel there is an issue with the code in this project, please submit a ticket on GitHub for help.

Command Line Use

This library can also be called from the command line. The XML to validate can either be piped into the library:

$ cat file-to-validate.xml | w3c-xml-validator

or the file name provided as an argument:

$ w3c-xml-validator file-to-validate.xml

The exit code will be non-zero if isValid === false. Any rejections will be output to stderr.

License

Please refer to LICENSE.