<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8" />
    <title>Wialon Playground</title>
</head>
<body>

</body>
</html>HTML

.log {
    margin-bottom: 1em;
}
.log p {
    margin: 0;
}CSS

let logEl = document.createElement('div');
logEl.className = 'log';
document.body.appendChild(logEl);

logMsg('start');

let pm = new WialonPostMessage({
	origin: 'https://hst-api.wialon.com',
	postHtmlUrl: 'https://hst-api.wialon.com/wialon/post.html',
	prefix: 'prefix:',
});

(async () => {
	await pm.init();

	let response = await pm.request({
		path: '/wialon/ajax.html',
		params: {
			svc: 'token/login',
			params: JSON.stringify({
				token:
					'5dce19710a5e26ab8b7b8986cb3c49e58C291791B7F0A7AEB8AFBFCEED7DC03BC48FF5F8',
				fl: 3,
			}),
		},
	});

	let { error, result } = response;
	logMsg(`Response got`);
	if (error) {
		logMsg(`Error ${error}`);
		return;
	}

	let {
		eid: sid,
		user: { nm: userName },
	} = result;
	logMsg(`sid "${sid}", user "${userName}"`);

	response = await pm.request({
		path: '/avl_evts',
		params: {
			sid,
		},
	});
	if (response.error) {
		logMsg(`/avl_evts error ${response.error}`);
		return;
	}

	logMsg(`/avl_evts: ${JSON.stringify(response.result)}`);
})().catch((error) => {
	logMsg('uncaught exception', error);
});

function logMsg(msg) {
	let p = document.createElement('p');
	p.textContent = msg;
	logEl.appendChild(p);
}

function WialonPostMessage(options) {
	let { prefix, origin, postHtmlUrl } = options;

	let frame;
	let messageHandler;

	let idCounter = 0;
	let requestsById = new Map();

	this.init = async function () {
		window.addEventListener('message', onMessage);

		let resolve;
		let promise = new Promise((_resolve) => {
			resolve = _resolve;
		});

		messageHandler = function (data) {
			try {
				data = JSON.parse(data);
			} catch (error) {
				return;
			}

			if (!data) {
				return;
			}

			// If there is no `chunkedResult`,
			// it's old Local, need to non-chunked mode support
			if (data.id === 0 && !data.error && data.chunkedResult) {
				resolve();
			}
		};

		frame = document.createElement('iframe');
		frame.addEventListener('load', () => {
			logMsg('frame load');

			frame.contentWindow.postMessage(
				JSON.stringify({
					id: 0,
					source: postHtmlUrl,
					chunkedPrefix: prefix,
					enableChunkedResult: true,
				}),
				'*',
			);
		});
		frame.src = postHtmlUrl;
		document.body.appendChild(frame);

		await promise;

		logMsg('post.html initialized');

		messageHandler = function (data) {
			if (typeof data !== 'string') {
				return;
			}

			if (data.slice(0, prefix.length) !== prefix) {
				return;
			}

			// Format: `prefix : id : chunk index : chunks count : chunk data`

			let colonAfterId = data.indexOf(':', prefix.length);
			let colonAfterChunkIndex = data.indexOf(':', colonAfterId + 1);
			let colonAfterChunksCount = data.indexOf(
				':',
				colonAfterChunkIndex + 1,
			);

			let invalid =
				colonAfterId < 0 ||
				colonAfterChunkIndex < 0 ||
				colonAfterChunksCount < 0;
			if (invalid) {
				return;
			}

			let id = data.slice(prefix.length, colonAfterId);
			let chunkIndex = data.slice(colonAfterId + 1, colonAfterChunkIndex);
			let chunksCount = data.slice(
				colonAfterChunkIndex + 1,
				colonAfterChunksCount,
			);

			id = parseInt(id, 10);
			chunkIndex = parseInt(chunkIndex, 10);
			chunksCount = parseInt(chunksCount, 10);

			invalid =
				!isFinite(id) ||
				!isFinite(chunkIndex) ||
				!isFinite(chunksCount);
			if (invalid) {
				return;
			}

			if (chunksCount === 1) {
				onResponse({ id, data: data.slice(colonAfterChunksCount + 1) });
				return;
			}

			logMsg('TODO: implement multiple chunks response concatenation');
			throw new Error('not implemented yet');
		};
	};

	this.request = function ({ path, params }) {
		idCounter++;
		let id = idCounter;

		let encodedParams = Object.entries(params)
			.map(([key, value]) => {
				return (
					encodeURIComponent(key) + '=' + encodeURIComponent(value)
				);
			})
			.join('&');

		let resolve;
		let reject;
		let promise = new Promise((_resolve, _reject) => {
			resolve = _resolve;
			reject = _reject;
		});

		requestsById.set(id, { resolve, reject });

		frame.contentWindow.postMessage(
			JSON.stringify({
				id,
				url: path,
				params: encodedParams,
				source: postHtmlUrl,
			}),
			'*',
		);

		return promise;
	};

	this.destroy = function () {
		if (frame && frame.parentNode) {
			frame.parentNode.removeChild(frame);
		}

		window.removeEventListener('message', onMessage);
	};

	function onResponse({ id, data }) {
		let handler = requestsById.get(id);
		if (!handler) {
			return;
		}

		try {
			data = JSON.parse(data);
		} catch (error) {
			handler.reject(error);
			return;
		}

		handler.resolve({
			error: data.error,
			result: data.text,
		});
	}

	function onMessage(event) {
		if (event.origin !== origin) {
			return;
		}

		if (!event.data) {
			return;
		}

		if (messageHandler) {
			messageHandler(event.data);
		}
	}
}
JS

Result

Source code of example Close ✕