@@ -121,13 +121,13 @@ class WebDavApi {
 			attrValueProcessors: [attrValueProcessor],
 		};
 
-		return new Promise((resolve) => {
+		return new Promise((resolve, reject) => {
 			parseXmlString(xml, options, (error, result) => {
 				if (error) {
-					resolve(null); // Error handled by caller which will display the XML text (or plain text) if null is returned from this function
-					return;
+					reject(error);
+				} else {
+					resolve(result);
 				}
-				resolve(result);
 			});
 		});
 	}
const Logger = require('./Logger').default;
const shim = require('./shim').default;
const parseXmlString = require('xml2js').parseString;
const JoplinError = require('./JoplinError').default;
const URL = require('url-parse');
const { rtrimSlashes } = require('./path-utils');
const base64 = require('base-64');


// Note that the d: namespace (the DAV namespace) is specific to Nextcloud. The RFC for example uses "D:" however
// we make all the tags and attributes lowercase so we handle both the Nextcloud style and RFC. Hopefully other
// implementations use the same namespaces. If not, extra processing can be done in `nameProcessor`, for
// example to convert a custom namespace to "d:" so that it can be used by the rest of the code.
// In general, we should only deal with things in "d:", which is the standard DAV namespace.

class WebDavApi {
	constructor(options) {
		this.logger_ = new Logger();
		this.options_ = options;
		this.lastRequests_ = [];
	}

	logRequest_(request, responseText) {
		if (this.lastRequests_.length > 10) this.lastRequests_.splice(0, 1);

		const serializeRequest = (r) => {
			const options = Object.assign({}, r.options);
			if (typeof options.body === 'string') options.body = options.body.substr(0, 4096);
			const output = [];
			output.push(options.method ? options.method : 'GET');
			output.push(r.url);
			options.headers = Object.assign({}, options.headers);
			if (options.headers['Authorization']) options.headers['Authorization'] = '********';
			delete options.method;
			delete options.agent;
			output.push(JSON.stringify(options));
			return output.join(' ');
		};

		this.lastRequests_.push({
			timestamp: Date.now(),
			request: serializeRequest(request),
			response: responseText ? responseText.substr(0, 4096) : '',
		});
	}

	lastRequests() {
		return this.lastRequests_;
	}

	clearLastRequests() {
		this.lastRequests_ = [];
	}

	setLogger(l) {
		this.logger_ = l;
	}

	logger() {
		return this.logger_;
	}

	authToken() {
		if (!this.options_.username() || !this.options_.password()) return null;
		try {
			// Note: Non-ASCII passwords will throw an error about Latin1 characters - https://github.com/laurent22/joplin/issues/246
			// Tried various things like the below, but it didn't work on React Native:
			// return base64.encode(utf8.encode(this.options_.username() + ':' + this.options_.password()));
			return base64.encode(`${this.options_.username()}:${this.options_.password()}`);
		} catch (error) {
			error.message = `Cannot encode username/password: ${error.message}`;
			throw error;
		}
	}

	baseUrl() {
		return rtrimSlashes(this.options_.baseUrl());
	}

	relativeBaseUrl() {
		const url = new URL(this.baseUrl());
		return url.pathname + url.query;
	}

	async xmlToJson(xml) {
		const davNamespaces = []; // Yes, there can be more than one... xmlns:a="DAV:" xmlns:D="DAV:"

		const nameProcessor = name => {
			if (name.indexOf('xmlns') !== 0) {
				// Check if the current name is within the DAV namespace. If it is, normalise it
				// by moving it to the "d:" namespace, which is what all the functions are using.
				const p = name.split(':');
				if (p.length == 2) {
					const ns = p[0];
					if (davNamespaces.indexOf(ns) >= 0) {
						name = `d:${p[1]}`;
					}
				} else if (p.length === 1 && davNamespaces.indexOf('') >= 0) {
					// Also handle the case where the namespace alias is empty.
					// https://github.com/laurent22/joplin/issues/2002
					name = `d:${name}`;
				}
			}

			return name.toLowerCase();
		};

		const attrValueProcessor = (value, name) => {
			// The namespace is ususally specified like so: xmlns:D="DAV:" ("D" being the alias used in the tag names)
			// In some cases, the namespace can also be empty like so: "xmlns=DAV". In this case, the tags will have
			// no namespace so instead of <d:prop> will have just <prop>. This is handled above in nameProcessor()
			if (value.toLowerCase() === 'dav:') {
				const p = name.split(':');
				davNamespaces.push(p.length === 2 ? p[p.length - 1] : '');
			}
		};

		const options = {
			tagNameProcessors: [nameProcessor],
			attrNameProcessors: [nameProcessor],
			attrValueProcessors: [attrValueProcessor],
		};

		return new Promise((resolve) => {
			parseXmlString(xml, options, (error, result) => {
				if (error) {
					resolve(null); // Error handled by caller which will display the XML text (or plain text) if null is returned from this function
					return;
				}
				resolve(result);
			});
		});
	}

	valueFromJson(json, keys, type) {
		let output = json;

		for (let i = 0; i < keys.length; i++) {
			const key = keys[i];

			// console.info(key, typeof key, typeof output, typeof output === 'object' && (key in output), Array.isArray(output));

			if (typeof key === 'number' && !Array.isArray(output)) return null;
			if (typeof key === 'string' && (typeof output !== 'object' || !(key in output))) return null;
			output = output[key];
		}

		if (type === 'string') {
			// If the XML has not attribute the value is directly a string
			// If the XML node has attributes, the value is under "_".
			// Eg for this XML, the string will be under {"_":"Thu, 01 Feb 2018 17:24:05 GMT"}:
			// <a:getlastmodified b:dt="dateTime.rfc1123">Thu, 01 Feb 2018 17:24:05 GMT</a:getlastmodified>
			// For this XML, the value will be "Thu, 01 Feb 2018 17:24:05 GMT"
			// <a:getlastmodified>Thu, 01 Feb 2018 17:24:05 GMT</a:getlastmodified>

			if (typeof output === 'object' && '_' in output) output = output['_'];
			if (typeof output !== 'string') return null;
			return output;
		}

		if (type === 'object') {
			if (!Array.isArray(output) && typeof output === 'object') return output;
			return null;
		}

		if (type === 'array') {
			return Array.isArray(output) ? output : null;
		}

		return null;
	}

	stringFromJson(json, keys) {
		return this.valueFromJson(json, keys, 'string');
	}

	objectFromJson(json, keys) {
		return this.valueFromJson(json, keys, 'object');
	}

	arrayFromJson(json, keys) {
		return this.valueFromJson(json, keys, 'array');
	}

	resourcePropByName(resource, outputType, propName) {
		const propStats = resource['d:propstat'];
		let output = null;
		if (!Array.isArray(propStats)) throw new Error('Missing d:propstat property');
		for (let i = 0; i < propStats.length; i++) {
			const props = propStats[i]['d:prop'];
			if (!Array.isArray(props) || !props.length) continue;
			const prop = props[0];
			if (Array.isArray(prop[propName])) {
				output = prop[propName];
				break;
			}
		}

		if (outputType === 'string') {
			if (!output) throw new JoplinError(`String property not found: ${propName}: ${JSON.stringify(resource)}`, 'stringNotFound');

			// If the XML has not attribute the value is directly a string
			// If the XML node has attributes, the value is under "_".
			// Eg for this XML, the string will be under {"_":"Thu, 01 Feb 2018 17:24:05 GMT"}:
			// <a:getlastmodified b:dt="dateTime.rfc1123">Thu, 01 Feb 2018 17:24:05 GMT</a:getlastmodified>
			// For this XML, the value will be "Thu, 01 Feb 2018 17:24:05 GMT"
			// <a:getlastmodified>Thu, 01 Feb 2018 17:24:05 GMT</a:getlastmodified>

			output = output[0];

			if (typeof output === 'object' && '_' in output) output = output['_'];
			if (typeof output !== 'string') return null;
			return output;
		}

		if (outputType === 'array') {
			return output;
		}

		throw new Error(`Invalid output type: ${outputType}`);
	}

	async execPropFind(path, depth, fields = null, options = null) {
		if (fields === null) fields = ['d:getlastmodified'];

		let fieldsXml = '';
		for (let i = 0; i < fields.length; i++) {
			fieldsXml += `<${fields[i]}/>`;
		}

		// To find all available properties:
		//
		// const body=`<?xml version="1.0" encoding="utf-8" ?>
		// 	<propfind xmlns="DAV:">
		// 	<propname/>
		// </propfind>`;

		const body =
			`<?xml version="1.0" encoding="UTF-8"?>
			<d:propfind xmlns:d="DAV:">
				<d:prop xmlns:oc="http://owncloud.org/ns">
					${fieldsXml}
				</d:prop>
			</d:propfind>`;

		return this.exec('PROPFIND', path, body, { Depth: depth }, options);
	}

	requestToCurl_(url, options) {
		const output = [];
		output.push('curl');
		output.push('-v');
		if (options.method) output.push(`-X ${options.method}`);
		if (options.headers) {
			for (const n in options.headers) {
				if (!options.headers.hasOwnProperty(n)) continue;
				output.push(`${'-H ' + '"'}${n}: ${options.headers[n]}"`);
			}
		}
		if (options.body) output.push(`${'--data ' + '\''}${options.body}'`);
		output.push(url);

		return output.join(' ');
	}

	handleNginxHack_(jsonResponse, newErrorHandler) {
		// Trying to fix 404 error issue with Nginx WebDAV server.
		// https://github.com/laurent22/joplin/issues/624
		// https://github.com/laurent22/joplin/issues/808
		// Not tested but someone confirmed it worked - https://github.com/laurent22/joplin/issues/808#issuecomment-443552858
		// and fix is narrowly scoped so shouldn't affect anything outside this particular edge case.
		//
		// The issue is that instead of an HTTP 404 status code, Nginx returns 200 but with this response:
		//
		// <?xml version="1.0" encoding="utf-8" ?>
		// <D:multistatus xmlns:D="DAV:">
		// 	<D:response>
		// 		<D:href>/notes/ecd4027a5271483984b00317433e2c66.md</D:href>
		// 		<D:propstat>
		// 			<D:prop/>
		// 			<D:status>HTTP/1.1 404 Not Found</D:status>
		// 		</D:propstat>
		// 	</D:response>
		// </D:multistatus>
		//
		// So we need to parse this and find that it is in fact a 404 error.
		//
		// HOWEVER, some implementations also return 404 for missing props, for example SeaFile:
		// (indicates that the props "getlastmodified" is not present, but this call is only
		// used when checking the conf, so we don't really need it)
		// https://github.com/laurent22/joplin/issues/1137
		//
		// <?xml version='1.0' encoding='UTF-8'?>
		// <ns0:multistatus xmlns:ns0="DAV:">
		// 	<ns0:response>
		// 		<ns0:href>/seafdav/joplin/</ns0:href>
		// 		<ns0:propstat>
		// 			<ns0:prop>
		// 				<ns0:getlastmodified/>
		// 			</ns0:prop>
		// 			<ns0:status>HTTP/1.1 404 Not Found</ns0:status>
		// 		</ns0:propstat>
		// 		<ns0:propstat>
		// 			<ns0:prop>
		// 				<ns0:resourcetype>
		// 					<ns0:collection/>
		// 				</ns0:resourcetype>
		// 			</ns0:prop>
		// 			<ns0:status>HTTP/1.1 200 OK</ns0:status>
		// 		</ns0:propstat>
		// 	</ns0:response>
		// </ns0:multistatus>
		//
		// As a simple fix for now it's enough to check if ALL the statuses are 404 - in that case
		// it really means that the file doesn't exist. Otherwise we can proceed as usual.
		const responseArray = this.arrayFromJson(jsonResponse, ['d:multistatus', 'd:response']);
		if (responseArray && responseArray.length === 1) {
			const propStats = this.arrayFromJson(jsonResponse, ['d:multistatus', 'd:response', 0, 'd:propstat']);
			if (!propStats.length) return;
			let count404 = 0;
			for (let i = 0; i < propStats.length; i++) {
				const status = this.arrayFromJson(jsonResponse, ['d:multistatus', 'd:response', 0, 'd:propstat', i, 'd:status']);
				if (status && status.length && status[0].indexOf('404') >= 0) count404++;
			}

			if (count404 === propStats.length) throw newErrorHandler('Not found', 404);
		}
	}

	// curl -u admin:123456 'http://nextcloud.local/remote.php/dav/files/admin/' -X PROPFIND --data '<?xml version="1.0" encoding="UTF-8"?>
	//  <d:propfind xmlns:d="DAV:">
	//    <d:prop xmlns:oc="http://owncloud.org/ns">
	//      <d:getlastmodified/>
	//    </d:prop>
	//  </d:propfind>'

	async exec(method, path = '', body = null, headers = null, options = null) {
		headers = Object.assign({}, headers);
		options = Object.assign({}, options);

		if (!options.responseFormat) options.responseFormat = 'json';
		if (!options.target) options.target = 'string';

		const authToken = this.authToken();

		if (authToken) headers['Authorization'] = `Basic ${authToken}`;

		// That should not be needed, but it is required for React Native 0.63+
		// https://github.com/facebook/react-native/issues/30176
		if (!headers['Content-Type']) {
			if (method === 'PROPFIND') headers['Content-Type'] = 'text/xml';
			if (method === 'PUT') headers['Content-Type'] = 'text/plain';
		}

		// React-native has caching enabled by at least on Android (see https://github.com/laurent22/joplin/issues/4706 and the related PR).
		// The below header disables caching for all versions, including desktop.
		// This can potentially also help with misconfigured caching on WebDAV server.
		if (!headers['Cache-Control']) {
			headers['Cache-Control'] = 'no-store';
		}

		// On iOS, the network lib appends a If-None-Match header to PROPFIND calls, which is kind of correct because
		// the call is idempotent and thus could be cached. According to RFC-7232 though only GET and HEAD should have
		// this header for caching purposes. It makes no mention of PROPFIND.
		// So possibly because of this, Seafile (and maybe other WebDAV implementations) responds with a "412 Precondition Failed"
		// error when this header is present for PROPFIND call on existing resources. This is also kind of correct because there is a resource
		// with this eTag and since this is neither a GET nor HEAD call, it is supposed to respond with 412 if the resource is present.
		// The "solution", an ugly one, is to send a purposely invalid string as eTag, which will bypass the If-None-Match check  - Seafile
		// finds out that no resource has this ID and simply sends the requested data.
		// Also add a random value to make sure the eTag is unique for each call.
		if (['GET', 'HEAD'].indexOf(method) < 0) headers['If-None-Match'] = `JoplinIgnore-${Math.floor(Math.random() * 100000)}`;
		if (!headers['User-Agent']) headers['User-Agent'] = 'Joplin/1.0';

		const fetchOptions = {};
		fetchOptions.headers = headers;
		fetchOptions.method = method;
		if (options.path) fetchOptions.path = options.path;
		if (body) fetchOptions.body = body;
		fetchOptions.ignoreTlsErrors = this.options_.ignoreTlsErrors();
		const url = `${this.baseUrl()}/${path}`;

		if (shim.httpAgent(url)) fetchOptions.agent = shim.httpAgent(url);

		let response = null;

		// console.info('WebDAV Call', `${method} ${url}`, headers, options);
		// console.info(this.requestToCurl_(url, fetchOptions));

		if (options.source == 'file' && (method == 'POST' || method == 'PUT')) {
			if (fetchOptions.path) {
				const fileStat = await shim.fsDriver().stat(fetchOptions.path);
				if (fileStat) fetchOptions.headers['Content-Length'] = `${fileStat.size}`;
			}
			response = await shim.uploadBlob(url, fetchOptions);
		} else if (options.target == 'string') {
			if (typeof body === 'string') fetchOptions.headers['Content-Length'] = `${shim.stringByteLength(body)}`;
			response = await shim.fetch(url, fetchOptions);
		} else {
			// file
			response = await shim.fetchBlob(url, fetchOptions);
		}

		const responseText = await response.text();

		this.logRequest_({ url: url, options: fetchOptions }, responseText);

		// console.info('WebDAV Response', responseText);

		// Creates an error object with as much data as possible as it will appear in the log, which will make debugging easier
		const newError = (message, code = 0) => {
			// Gives a shorter response for error messages. Useful for cases where a full HTML page is accidentally loaded instead of
			// JSON. That way the error message will still show there's a problem but without filling up the log or screen.
			const shortResponseText = (`${responseText}`).substr(0, 1024);
			return new JoplinError(`${method} ${path}: ${message} (${code}): ${shortResponseText}`, code);
		};

		let responseJson_ = null;
		const loadResponseJson = async () => {
			if (!responseText) return null;
			if (responseJson_) return responseJson_;
			// eslint-disable-next-line require-atomic-updates
			responseJson_ = await this.xmlToJson(responseText);
			if (!responseJson_) throw newError('Cannot parse XML response', response.status);
			return responseJson_;
		};

		if (!response.ok) {
			// When using fetchBlob we only get a string (not xml or json) back
			if (options.target === 'file') throw newError('fetchBlob error', response.status);

			let json = null;
			try {
				json = await loadResponseJson();
			} catch (error) {
				// Just send back the plain text in newErro()
			}

			if (json && json['d:error']) {
				const code = json['d:error']['s:exception'] ? json['d:error']['s:exception'].join(' ') : response.status;
				const message = json['d:error']['s:message'] ? json['d:error']['s:message'].join('\n') : 'Unknown error 1';
				throw newError(`${message} (Exception ${code})`, response.status);
			}

			throw newError('Unknown error 2', response.status);
		}

		if (options.responseFormat === 'text') return responseText;

		// The following methods may have a response depending on the server but it's not
		// standard (some return a plain string, other XML, etc.) and we don't check the
		// response anyway since we rely on the HTTP status code so return null.
		if (['MKCOL', 'DELETE', 'PUT', 'MOVE'].indexOf(method) >= 0) return null;

		const output = await loadResponseJson();
		if (output) this.handleNginxHack_(output, newError);

		// Check that we didn't get for example an HTML page (as an error) instead of the JSON response
		// null responses are possible, for example for DELETE calls
		if (output !== null && typeof output === 'object' && !('d:multistatus' in output)) throw newError('Not a valid WebDAV response');

		return output;
	}
}

module.exports = WebDavApi;

What would the error message be in this case? Because what sometimes happen is that the WebDAV service will return random data, like HTML or a plain text and in that case the parsing error is not useful. Like if the service returns a plain string "disk quota exceeded", it's not useful to display "parsing error at character 1", but sending back the full string, as we currently do, might help understand the problem. The thing is that we can't expect getting anything sensible from the various WebDAV implementations. They are supposed to always return XML but in practice there are many poor implementations that return whatever data on failure.