albanm/nsi-routes

// A route builder that create routes for validating XML messages against a XSD schema
// The schema is fetched from a file and the file's changes are watched automatically

var fs = require('fs');
var path = require('path');
libxml = require('libxmljs');

module.exports = function xsd(fileName, routeName) {
    var that = this;
    var schema = null;
    routeName = routeName || 'validate-xsd.' + path.basename(fileName, '.xsd');

    that.log('info', routeName + ' - Initialize');

    if (that.options.watch) {
        fs.watch(fileName, {
            persistent: false
        }, function() {
            that.log('info', routeName + ' - Schema changed');
            schema = null;
        });
    }

    return that.wrap(function(message, headers, callback) {
        var xmlMessage = libxml.parseXmlString(message);
        if (!schema) {
            fs.readFile(fileName, 'utf8', function(err, data) {
                if (err) throw err;
                schema = libxml.parseXmlString(data);
                that.log('info', routeName + ' - Schema loaded');

                var valid = xmlMessage.validate(schema);
                if (!valid) callback(xmlMessage.validationErrors, message, headers);
                else callback(null, message, headers);
            });
        } else {
            // use nextTick to make the route asynchronous
            process.nextTick(function() {
                var valid = xmlMessage.validate(schema);
                if (!valid) callback(xmlMessage.validationErrors, message, headers);
                else callback(null, message, headers);
            });
        }
    }, routeName);
};