add apns token methods

src/notifications/senders/AppleNotificationSender.ts

@@ -0,0 +1,73 @@
+import jwt from "jsonwebtoken";
+
+interface APNsUrl {
+  fullUrl: string;
+  path: string;
+  host: string;
+}
+
+class AppleNotificationSender {
+  private apnsToken: string | undefined = undefined;
+  private _lastRefreshedTimeMs: number | undefined = undefined;
+
+  private lastReloadedTimeForAPNsIsTooRecent() {
+    const thirtyMinutesMs = 1800000;
+    return this._lastRefreshedTimeMs && Date.now() - this._lastRefreshedTimeMs < thirtyMinutesMs;
+  }
+
+  private reloadAPNsTokenIfTimePassed() {
+    if (this.lastReloadedTimeForAPNsIsTooRecent()) {
+      return;
+    }
+
+    const keyId = process.env.APNS_KEY_ID;
+    const teamId = process.env.APNS_TEAM_ID;
+
+    const privateKeyBase64 = process.env.APNS_PRIVATE_KEY;
+    if (!privateKeyBase64) return;
+    const privateKey = Buffer.from(privateKeyBase64, 'base64').toString('utf-8');
+
+    const tokenHeader = {
+      alg: "ES256",
+      "kid": keyId,
+    };
+
+    const nowMs = Date.now();
+    const claimsPayload = {
+      "iss": teamId,
+      "iat": Math.ceil(nowMs / 1000),  // APNs requires number of seconds since Epoch
+    };
+
+    this.apnsToken = jwt.sign(claimsPayload, privateKey, {
+      algorithm: "ES256",
+      header: tokenHeader
+    });
+    this._lastRefreshedTimeMs = nowMs;
+  }
+
+  public sendNotificationImmediately(notification: any) {
+    // TODO Send the notification
+  }
+
+  public static getAPNsFullUrlToUse(deviceId: string): APNsUrl {
+    // Construct the fetch request
+    const devBaseUrl = "https://api.development.push.apple.com"
+    const prodBaseUrl = "https://api.push.apple.com"
+
+    let hostToUse = devBaseUrl;
+    if (process.env.APNS_IS_PRODUCTION === "1") {
+      hostToUse = prodBaseUrl;
+    }
+
+    const path = "/3/device/" + deviceId;
+    const fullUrl = hostToUse + path;
+
+    const constructedObject = {
+      fullUrl,
+      host: hostToUse,
+      path,
+    }
+    return constructedObject;
+  }
+
+}