1 files changed, 116 insertions, 0 deletions
diff --git a/packages/taler-util/src/http-client/utils.ts b/packages/taler-util/src/http-client/utils.ts
new file mode 100644
index 000000000..bf186ce46
--- /dev/null
+++ b/packages/taler-util/src/http-client/utils.ts
@@ -0,0 +1,116 @@
+/*
+ This file is part of GNU Taler
+ (C) 2022-2024 Taler Systems S.A.
+
+ GNU Taler is free software; you can redistribute it and/or modify it under the
+ terms of the GNU General Public License as published by the Free Software
+ Foundation; either version 3, or (at your option) any later version.
+
+ GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along with
+ GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+/**
+ * Imports.
+ */
+import { base64FromArrayBuffer } from "../base64.js";
+import { encodeCrock, getRandomBytes, stringToBytes } from "../taler-crypto.js";
+import { AccessToken, LongPollParams, PaginationParams } from "./types.js";
+
+/**
+ * Helper function to generate the "Authorization" HTTP header.
+ */
+export function makeBasicAuthHeader(
+  username: string,
+  password: string,
+): string {
+  const auth = `${username}:${password}`;
+  const authEncoded: string = base64FromArrayBuffer(stringToBytes(auth));
+  return `Basic ${authEncoded}`;
+}
+
+/**
+ * rfc8959
+ * @param token
+ * @returns
+ */
+export function makeBearerTokenAuthHeader(token: AccessToken): string {
+  return `Bearer ${token}`;
+}
+
+/**
+ * https://bugs.gnunet.org/view.php?id=7949
+ */
+export function addPaginationParams(url: URL, pagination?: PaginationParams) {
+  if (!pagination) return;
+  if (pagination.offset) {
+    url.searchParams.set("start", pagination.offset);
+  }
+  const order = !pagination || pagination.order === "asc" ? 1 : -1;
+  const limit =
+    !pagination || !pagination.limit || pagination.limit === 0
+      ? 5
+      : Math.abs(pagination.limit);
+  //always send delta
+  url.searchParams.set("delta", String(order * limit));
+}
+
+export function addMerchantPaginationParams(
+  url: URL,
+  pagination?: PaginationParams,
+) {
+  if (!pagination) return;
+  if (pagination.offset) {
+    url.searchParams.set("offset", pagination.offset);
+  }
+  const order = !pagination || pagination.order === "asc" ? 1 : -1;
+  const limit =
+    !pagination || !pagination.limit || pagination.limit === 0
+      ? 5
+      : Math.abs(pagination.limit);
+  //always send delta
+  url.searchParams.set("limit", String(order * limit));
+}
+
+export function addLongPollingParam(url: URL, param?: LongPollParams) {
+  if (!param) return;
+  if (param.timeoutMs) {
+    url.searchParams.set("long_poll_ms", String(param.timeoutMs));
+  }
+}
+
+export interface CacheEvictor<T> {
+  notifySuccess: (op: T) => Promise<void>;
+}
+
+export const nullEvictor: CacheEvictor<unknown> = {
+  notifySuccess: () => Promise.resolve(),
+};
+
+export class IdempotencyRetry {
+  public readonly uid: string;
+  public readonly timesLeft: number;
+  public readonly maxTries: number;
+
+  private constructor(timesLeft: number, maxTimesLeft: number) {
+    this.timesLeft = timesLeft;
+    this.maxTries = maxTimesLeft;
+    this.uid = encodeCrock(getRandomBytes(32))
+  }
+  
+  static tryFiveTimes() {
+    return new IdempotencyRetry(5, 5)
+  }
+
+  next(): IdempotencyRetry | undefined {
+    const left = this.timesLeft -1
+    if (left <= 0) {
+      return undefined
+    }
+    return new IdempotencyRetry(left, this.maxTries);
+  }
+}