Initial

resources/app/common/utils/http.mjs

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+/**
+ * A wrapper method around `fetch` that attaches an AbortController signal to the `fetch` call for clean timeouts
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/AbortSignal#aborting_a_fetch_with_timeout_or_explicit_abort
+ * @param {string} url            The URL to make the Request to
+ * @param {Object} data           The data of the Request
+ * @param {number|null} timeoutMs How long to wait for a Response before cleanly aborting.
+ *                                If null, no timeout is applied
+ * @param {function} onTimeout    A method to invoke if and when the timeout is reached
+ * @return {Promise<Response>}
+ * @throws {HttpError}
+ */
+export async function fetchWithTimeout(url, data = {}, {timeoutMs=30000, onTimeout = () => {}} = {}) {
+  const controller = new AbortController();
+  data.signal = controller.signal;
+  let timedOut = false;
+  const enforceTimeout = timeoutMs !== null;
+
+  // Enforce a timeout
+  let timeout;
+  if ( enforceTimeout ) {
+    timeout = setTimeout(() => {
+      timedOut = true;
+      controller.abort();
+      onTimeout();
+    }, timeoutMs);
+  }
+
+  // Attempt the request
+  let response;
+  try {
+    response = await fetch(url, data);
+  } catch(err) {
+    if ( timedOut ) {
+      const timeoutS = Math.round(timeoutMs / 1000);
+      const msg = game.i18n
+        ? game.i18n.format("SETUP.ErrorTimeout", { url, timeout: timeoutS })
+        : `The request to ${url} timed out after ${timeoutS}s.`;
+      throw new HttpError("Timed Out", 408, msg);
+    }
+    throw err;
+  } finally {
+    if ( enforceTimeout ) clearTimeout(timeout);
+  }
+
+  // Return the response
+  if ( !response.ok && (response.type !== "opaqueredirect") ) {
+    const responseBody = response.body ? await response.text() : "";
+    throw new HttpError(response.statusText, response.status, responseBody);
+  }
+  return response;
+}
+
+/* ----------------------------------------- */
+
+/**
+ * A small wrapper that automatically asks for JSON with a Timeout
+ * @param {string} url          The URL to make the Request to
+ * @param {Object} data         The data of the Request
+ * @param {int} timeoutMs       How long to wait for a Response before cleanly aborting
+ * @param {function} onTimeout  A method to invoke if and when the timeout is reached
+ * @returns {Promise<*>}
+ */
+export async function fetchJsonWithTimeout(url, data = {}, {timeoutMs=30000, onTimeout = () => {}} = {}) {
+  let response = await fetchWithTimeout(url, data, {timeoutMs: timeoutMs, onTimeout: onTimeout});
+  return response.json();
+}
+
+/* ----------------------------------------- */
+
+/**
+ * Represents an HTTP Error when a non-OK response is returned by Fetch
+ * @extends {Error}
+ */
+export class HttpError extends Error {
+  constructor(statusText, code, displayMessage="") {
+    super(statusText);
+    this.code = code;
+    this.displayMessage = displayMessage;
+  }
+
+  /* -------------------------------------------- */
+
+  /** @override */
+  toString() {
+    return this.displayMessage;
+  }
+}