ezdev-onvif/lib/utils.js

Client to ONVIF NVT devices Profile S: cameras

/**
 * @namespace utils
 * @description Common utils module
 * @author Andrew D.Laptev <a.d.laptev@gmail.com>
 * @licence MIT
 */

const xml2js = require('xml2js')
	, numberRE = /^-?([1-9]\d*|0)(\.\d*)?$/
	, dateRE = /^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}(.\d+)?Z$/
	, prefixMatch = /(?!xmlns)^.*:/
	;

/**
 * Parse SOAP object to pretty JS-object
 * @param {object} xml
 * @returns {object}
 */
const linerase = function(xml) {
	if (Array.isArray(xml)) {
		if (xml.length > 1) {
			return xml.map(linerase);
		} else {
			xml = xml[0];
		}
	}
	if (typeof xml === 'object') {
		var obj = {};
		Object.keys(xml).forEach(function(key) {
			if (key === '$') {
				obj.$ = linerase(xml.$);
			} else {
				obj[key] = linerase(xml[key]);
			}
		});
		return obj;
	} else {
		if (xml === 'true') { return true; }
		if (xml === 'false') { return false; }
		if (numberRE.test(xml)) { return parseFloat(xml); }
		if (dateRE.test(xml)) { return new Date(xml); }
		return xml;
	}
};

/**
 * @callback ParseSOAPStringCallback
 * @property {?Error} error
 * @property {object} SOAP response
 * @property {string} raw XML
 */

/**
 * Parse SOAP response
 * @param {string} xml
 * @param {ParseSOAPStringCallback} callback
 */
const parseSOAPString = function(xml, callback) {
	/* Filter out xml name spaces */
	xml = xml.replace(/xmlns(.*?)=(".*?")/g,'');

	xml2js.parseString(
		xml
		, {
			tagNameProcessors: [function(str) {
				str = str.replace(prefixMatch, '');
				var secondLetter = str.charAt(1);
				if (secondLetter && secondLetter.toUpperCase() !== secondLetter) {
					return str.charAt(0).toLowerCase() + str.slice(1);
				} else {
					return str;
				}
			}]
		}
		, function(err, result) {
			if (!result || !result['envelope'] || !result['envelope']['body']) {
				callback(new Error('Wrong ONVIF SOAP response'), null, xml);
			} else {
				if (!err && result['envelope']['body'][0]['fault']) {
					err = new Error(
						'ONVIF SOAP Fault: ' +
						(
							result.envelope.body[0].fault[0].reason[0].text[0]._
							||
							JSON.stringify(linerase(result.envelope.body[0].fault[0].code[0]))
						) +
						(
							result.envelope.body[0].fault[0].detail
							? ': ' + result.envelope.body[0].fault[0].detail[0].text[0]
							: ''
						)
					);
				}
				callback(err, result['envelope']['body'], xml);
			}
		});
};

const s4 = function() {
	return (((1 + Math.random()) * 0x10000) | 0).toString(16).substring(1);
};

/**
 * Generate GUID
 * @returns {string}
 */
const guid = function() {
	return (s4() + s4() + '-' + s4() + '-' + s4() + '-' + s4() + '-' + s4() + s4() + s4());
};

module.exports = {
	linerase: linerase
	, parseSOAPString: parseSOAPString
	, guid: guid
};