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) {
			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
 * @property {number} HTTP Status Code
 */

/**
 * Parse SOAP response
 * @param {string} xml
 * @param {ParseSOAPStringCallback} callback
 * @param {number} statusCode. This is passed in so it can be passed back out to the callback
 */
const parseSOAPString = function(xml, callback, statusCode) {
	/* Filter out xml name spaces */
	xml = xml.replace(/xmlns([^=]*?)=(".*?")/g, '');

	try {
		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, statusCode);
				} else {
					if (!err && result['envelope']['body'][0]['fault']) {
						var fault = result['envelope']['body'][0]['fault'][0];
						var reason;
						try {
							if (fault.reason[0].text[0]._) {
								reason = fault.reason[0].text[0]._;
							}
						} catch (e) {
							reason = '';
						}
						if (!reason) {
							try {
								reason = JSON.stringify(linerase(fault.code[0]));
							} catch (e) {
								reason = '';
							}
						}
						var detail = '';
						try {
							detail = fault.detail[0].text[0];
						} catch (e) {
							detail = '';
						}

						// console.error('Fault:', reason, detail);
						err = new Error('ONVIF SOAP Fault: ' + (reason) + (detail));
					}
					callback(err, result['envelope']['body'], xml, statusCode);
				}
			}
		);
	} catch (err) {
		callback(err, '', xml, statusCode);
	}
};

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
};