1 files changed, 42 insertions, 0 deletions
diff --git a/netwerk/protocol/http/HPKEConfigManager.sys.mjs b/netwerk/protocol/http/HPKEConfigManager.sys.mjs
new file mode 100644
index 0000000000..b08cc892c5
--- /dev/null
+++ b/netwerk/protocol/http/HPKEConfigManager.sys.mjs
@@ -0,0 +1,42 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+let knownConfigs = new Map();
+
+export class HPKEConfigManager {
+  static async get(aURL, aOptions = {}) {
+    try {
+      let config = await this.#getInternal(aURL, aOptions);
+      return new Uint8Array(config);
+    } catch (ex) {
+      console.error(ex);
+      return null;
+    }
+  }
+
+  static async #getInternal(aURL, aOptions = {}) {
+    let { maxAge = -1 } = aOptions;
+    let knownConfig = knownConfigs.get(aURL);
+    if (
+      knownConfig &&
+      (maxAge < 0 || Date.now() - knownConfig.fetchDate < maxAge)
+    ) {
+      return knownConfig.config;
+    }
+    return this.fetchAndStore(aURL, aOptions);
+  }
+
+  static async fetchAndStore(aURL, aOptions = {}) {
+    let fetchDate = Date.now();
+    let resp = await fetch(aURL, { signal: aOptions.abortSignal });
+    if (!resp?.ok) {
+      throw new Error(
+        `Fetching HPKE config from ${aURL} failed with error ${resp.status}`
+      );
+    }
+    let config = await resp.blob().then(b => b.arrayBuffer());
+    knownConfigs.set(aURL, { config, fetchDate });
+    return config;
+  }
+}