Fixing XMLHttpRequest polyfill

Author: Pauan

sdk/package.json

@@ -51,6 +51,7 @@
     "comlink": "^4.4.2",
     "core-js": "^3.40.0",
     "mime": "^4.0.6",
+    "sync-request": "^6.1.0",
     "xmlhttprequest-ssl": "^3.1.0"
   },
   "devDependencies": {

sdk/rollup.config.js

@@ -27,6 +27,7 @@ export default networks.map((network) => {
             "node:fs",
             "node:crypto",
             "mime/lite",
+            "sync-request",
             "xmlhttprequest-ssl",
 
             // Used by the SDK

sdk/rollup.test.js

@@ -34,6 +34,7 @@ export default networks.map((network) => {
             "node:fs",
             "node:crypto",
             "mime/lite",
+            "sync-request",
             "xmlhttprequest-ssl",
 
             // Used by the SDK

sdk/src/polyfill/xmlhttprequest.ts

@@ -1,6 +1,67 @@
 // @ts-ignore
 import $xmlhttprequest from "xmlhttprequest-ssl";
+import $request from "sync-request";
 
 if (globalThis.XMLHttpRequest == null) {
-    globalThis.XMLHttpRequest = $xmlhttprequest.XMLHttpRequest;
+    globalThis.XMLHttpRequest = class extends $xmlhttprequest.XMLHttpRequest {
+        // We have to override the methods inside of the `constructor`
+        // because `xmlhttprequest-ssl` doesn't use a regular class,
+        // instead it defines all of the methods inside of the constructor.
+        constructor(...args: Array<any>) {
+            super(...args);
+
+            const open = (this as any).open;
+            const send = (this as any).send;
+
+            let _async: boolean = true;
+            let _url: null | string = null;
+            let _mime: string = "text/xml";
+
+            function reset() {
+                _async = true;
+                _url = null;
+                _mime = "text/xml";
+            }
+
+            (this as any).open = function (method: string, url: string, async: boolean, user?: string, password?: string) {
+                // Special behavior for synchronous requests
+                if (method === "GET" && !async && !user && !password) {
+                    _async = false;
+                    _url = url;
+
+                // Default to the normal polyfill for async requests
+                } else {
+                    reset();
+                    return open.call(this, method, url, async, user, password);
+                }
+            };
+
+            (this as any).send = function (data: any) {
+                if (_async) {
+                    return send.call(this, data);
+
+                // Use `sync-request` for synchronous requests.
+                } else {
+                    const response = $request("GET", _url!, {
+                        headers: {
+                            "Content-Type": _mime,
+                        }
+                    });
+
+                    const buffer = (response.body as Buffer).buffer as any;
+
+                    const responseText = new TextDecoder("iso-8859-5", { fatal: true }).decode(buffer);
+
+                    (this as any).status = 200;
+                    (this as any).response = (this as any).responseText = responseText;
+
+                    reset();
+                }
+            };
+
+            (this as any).overrideMimeType = function (mime: string) {
+                _mime = mime;
+            };
+        }
+    } as any;
 }