albanm/nsi-routes

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

var fs = require('fs');
var path = require('path');
var JaySchema = require('jayschema');
var js = new JaySchema();

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

    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 objectMessage = message;
        if (typeof message === 'string') objectMessage = JSON.parse(message);
        if (!schema) {
            fs.readFile(fileName, 'utf8', function(err, data) {
                if (err) throw err;
                schema = JSON.parse(data);
                that.log('info', routeName + ' - Schema loaded');
                js.validate(objectMessage, schema, function(errs) {
                    callback(errs, message, headers);
                });
            });
        } else {
            js.validate(objectMessage, schema, function(errs) {
                callback(errs, message, headers);
            });
        }
    }, routeName);
};