01ea84935f132ebf7713cbf4f7a242eea3ffe791
[vchess.git] / client / src / utils / ajax.js
1 import params from "../parameters"; //for server URL
2
3 // TODO: replace by fetch API ?
4 // https://www.sitepoint.com/xmlhttprequest-vs-the-fetch-api-whats-best-for-ajax-in-2019/
5
6 // From JSON (encoded string values!) to "arg1=...&arg2=..."
7 function toQueryString(data)
8 {
9 let data_str = "";
10 Object.keys(data).forEach(k => {
11 data_str += k + "=" + encodeURIComponent(data[k]) + "&";
12 });
13 return data_str.slice(0, -1); //remove last "&"
14 }
15
16 // data, error: optional
17 export function ajax(url, method, data, success, error)
18 {
19 let xhr = new XMLHttpRequest();
20 if (typeof(data) === "function") //no data
21 {
22 error = success;
23 success = data;
24 data = {};
25 }
26 if (!error)
27 error = errmsg => { alert(errmsg); };
28
29 xhr.onreadystatechange = function() {
30 if (this.readyState == 4 && this.status == 200)
31 {
32 let res_json = "";
33 try {
34 res_json = JSON.parse(xhr.responseText);
35 } catch (e) {
36 // Plain text (e.g. for rules retrieval)
37 return success(xhr.responseText);
38 }
39 if (!res_json.errmsg)
40 success(res_json);
41 else
42 error(res_json.errmsg);
43 }
44 };
45
46 if (["GET","DELETE"].includes(method) && !!data)
47 {
48 // Append query params to URL
49 url += "/?" + toQueryString(data);
50 }
51 xhr.open(method, params.serverUrl + url, true);
52 xhr.setRequestHeader('X-Requested-With', "XMLHttpRequest");
53 // Next line to allow cross-domain cookies in dev mode (TODO: if...)
54 if (params.cors)
55 xhr.withCredentials = true;
56 if (["POST","PUT"].includes(method))
57 {
58 xhr.setRequestHeader("Content-Type", "application/json;charset=UTF-8");
59 xhr.send(JSON.stringify(data));
60 }
61 else
62 xhr.send();
63 }