https://portagemi.gov/Assets/Scripts/APIClient.js

1function CPAPIClient() {
2	this._bearer = function () {
3		return localStorage.getItem("ApiBearerToken");
4	};
5
6	this._clearBearer = function () {
7		localStorage.removeItem("ApiBearerToken")
8	}
9
10	this._request = function (url, method, payload, callback, error) {
11		var retries = 3;
12		var self = this;
13		payload = payload && typeof payload === "object" ? JSON.stringify(payload) : payload;
14
15		function invokeWithFreshBearer(xhr) {
16			var req = new XMLHttpRequest();
17			req.open("GET", "/GetBearerToken");
18			req.addEventListener("load", function () {
19				var bearer = JSON.parse(this.responseText);
20				localStorage.setItem("ApiBearerToken", bearer);
21				xhr.setRequestHeader("Authorization", "Bearer " + bearer);
22				xhr.send(payload);
23			})
24			req.send();
25		}
26
27		function makeRequest() {
28			var xhr = new XMLHttpRequest()
29			xhr.open(method, url);
30			xhr.addEventListener("load", function () {
31				if (this.status === 401 && retries > 0) {
32					console.log("Token expired. Retrying...", retries);
33					retries--;
34					self._clearBearer();
35					makeRequest();
36					return;
37				}
38				if (this.status >= 400 || retries < 1) {
39					(typeof error === 'function') && error({xhr: this, error: "Request Failed!"});
40					return;
41				}
42				try {
43					var obj = JSON.parse(this.responseText);
44					callback(obj);
45				} catch (e) {
46					(typeof error === 'function') && error({xhr: this, error: e});
47					console.error(e);
48				}
49			});
50			(method === "POST") && xhr.setRequestHeader("Content-Type", "application/json; charset=utf-8");
51			var bearer = self._bearer();
52			if (!bearer) {
53				invokeWithFreshBearer(xhr);
54				return;
55			}
56			xhr.setRequestHeader("Authorization", "Bearer " + bearer);
57			xhr.send(payload);
58		}
59
60		makeRequest();
61	};
62
63	this.get = function (url, callback, error) {
64		return this._request(url, "GET", null, callback, error);
65	};
66
67	this.post = function (url, payload, callback, error) {
68		return this._request(url, "POST", payload, callback, error);
69	}
70}