Implement session management with express-session and MemoryStorage

lib/main.test.ts

@@ -60,6 +60,7 @@ describe("index exports", () => {
       "LocalStorage",
       "storageSettings",
       "ExpoSecureStore",
+      "ExpressStore",
 
       // token utils
       "getActiveStorage",

lib/main.ts

@@ -57,6 +57,7 @@ export {
   ChromeStore,
   LocalStorage,
   StorageKeys,
+  ExpressStore,
 } from "./sessionManager";
 
 // This export provides an implementation of SessionManager<V>

lib/sessionManager/index.ts

@@ -25,6 +25,7 @@ export { MemoryStorage } from "./stores/memory.js";
 export { ChromeStore } from "./stores/chromeStore.js";
 export { ExpoSecureStore } from "./stores/expoSecureStore.js";
 export { LocalStorage } from "./stores/localStorage.ts";
+export { ExpressStore } from "./stores/expressStore.ts";
 
 // Export types directly
 export { StorageKeys } from "./types.ts";

lib/sessionManager/stores/expressStore.test.ts

@@ -0,0 +1,154 @@
+import { describe, it, expect, beforeEach, vi } from "vitest";
+import { ExpressStore } from "../../main";
+import { StorageKeys } from "../types";
+import type { Request } from "express";
+import { storageSettings } from "..";
+
+const mockRequest = (
+  sessionData: Record<string, unknown> | null,
+  destroyError: Error | null = null,
+) => {
+  const session = sessionData
+    ? {
+        ...sessionData,
+        destroy: vi.fn((callback: (err: Error | null) => void) => {
+          callback(destroyError);
+        }),
+      }
+    : undefined;
+
+  return {
+    session,
+  } as unknown as Request;
+};
+
+describe("ExpressStore", () => {
+  let req: Request;
+  let sessionManager: ExpressStore;
+
+  describe("constructor", () => {
+    it("should throw an error if session is not available on the request", () => {
+      req = mockRequest(null);
+      expect(() => new ExpressStore(req)).toThrow(
+        "Session not available on the request. Please ensure the 'express-session' middleware is configured and running before the Kinde middleware.",
+      );
+    });
+
+    it("should not throw an error if session is available on the request", () => {
+      req = mockRequest({});
+      expect(() => new ExpressStore(req)).not.toThrow();
+    });
+  });
+
+  describe("with a valid session", () => {
+    const keyPrefix = storageSettings.keyPrefix;
+    beforeEach(() => {
+      const initialSession = {
+        [`${keyPrefix}${StorageKeys.accessToken}0`]: "access-token",
+        [`${keyPrefix}${StorageKeys.idToken}0`]: "id-token",
+      };
+      req = mockRequest(initialSession);
+      sessionManager = new ExpressStore(req);
+    });
+
+    it("should get an item from the session", async () => {
+      const accessToken = await sessionManager.getSessionItem(
+        StorageKeys.accessToken,
+      );
+      expect(accessToken).toBe("access-token");
+    });
+
+    it("should return null for a non-existent item", async () => {
+      const refreshToken = await sessionManager.getSessionItem(
+        StorageKeys.refreshToken,
+      );
+      expect(refreshToken).toBeNull();
+    });
+
+    it("should set an item in the session", async () => {
+      await sessionManager.setSessionItem(
+        StorageKeys.refreshToken,
+        "refresh-token",
+      );
+      expect(req.session![`${keyPrefix}${StorageKeys.refreshToken}0`]).toBe(
+        "refresh-token",
+      );
+    });
+
+    it("should remove an item from the session", async () => {
+      await sessionManager.removeSessionItem(StorageKeys.accessToken);
+      expect(
+        req.session![`${keyPrefix}${StorageKeys.accessToken}0`],
+      ).toBeUndefined();
+    });
+
+    it("should destroy the session", async () => {
+      await sessionManager.destroySession();
+      expect(req.session!.destroy).toHaveBeenCalled();
+    });
+
+    it("should reject with an error if destroying the session fails", async () => {
+      const error = new Error("Failed to destroy Kinde session");
+      req = mockRequest({}, error);
+      sessionManager = new ExpressStore(req);
+      await expect(sessionManager.destroySession()).rejects.toThrow(error);
+    });
+  });
+
+  describe("splitting and reassembly logic", () => {
+    const longString = "a".repeat(5000); // longer than default maxLength (2000)
+    const keyPrefix = storageSettings.keyPrefix;
+    const maxLength = storageSettings.maxLength;
+    let req: Request;
+    let sessionManager: ExpressStore;
+
+    beforeEach(() => {
+      req = mockRequest({});
+      sessionManager = new ExpressStore(req);
+    });
+
+    it("should split and store a long string value across multiple session keys", async () => {
+      await sessionManager.setSessionItem(StorageKeys.state, longString);
+      expect(req.session![`${keyPrefix}state0`]).toBe(
+        longString.slice(0, maxLength),
+      );
+      expect(req.session![`${keyPrefix}state1`]).toBe(
+        longString.slice(maxLength, maxLength * 2),
+      );
+      expect(req.session![`${keyPrefix}state2`]).toBe(
+        longString.slice(maxLength * 2),
+      );
+      expect(req.session![`${keyPrefix}state3`]).toBeUndefined();
+    });
+
+    it("should reassemble a long string value from multiple session keys", async () => {
+      // Simulate split storage
+      req.session![`${keyPrefix}state0`] = longString.slice(0, maxLength);
+      req.session![`${keyPrefix}state1`] = longString.slice(
+        maxLength,
+        maxLength * 2,
+      );
+      req.session![`${keyPrefix}state2`] = longString.slice(maxLength * 2);
+      const value = await sessionManager.getSessionItem(StorageKeys.state);
+      expect(value).toBe(longString);
+    });
+
+    it("should remove all split keys for a long string value", async () => {
+      req.session![`${keyPrefix}state0`] = "part1";
+      req.session![`${keyPrefix}state1`] = "part2";
+      req.session![`${keyPrefix}state2`] = "part3";
+      await sessionManager.removeSessionItem(StorageKeys.state);
+      expect(req.session![`${keyPrefix}state0`]).toBeUndefined();
+      expect(req.session![`${keyPrefix}state1`]).toBeUndefined();
+      expect(req.session![`${keyPrefix}state2`]).toBeUndefined();
+    });
+
+    it("should store and retrieve non-string values without splitting", async () => {
+      const obj = { foo: "bar" };
+      await sessionManager.setSessionItem(StorageKeys.nonce, obj);
+      expect(req.session![`${keyPrefix}nonce0`]).toEqual(obj);
+      const value = await sessionManager.getSessionItem(StorageKeys.nonce);
+      expect(value).toEqual(obj); // Should return the original object
+    });
+  });
+});

lib/sessionManager/stores/expressStore.ts

@@ -0,0 +1,125 @@
+import type { Request } from "express";
+import { SessionBase, StorageKeys, type SessionManager } from "../types.js";
+import { storageSettings } from "../index.js";
+import { splitString } from "../../utils/splitString.js";
+
+declare global {
+  // eslint-disable-next-line @typescript-eslint/no-namespace
+  namespace Express {
+    interface Request {
+      session?: {
+        [key: string]: unknown;
+        destroy: (callback: (err?: Error | null) => void) => void;
+      };
+    }
+  }
+}
+
+/**
+ * Provides an Express session-based session manager.
+ * This class acts as a structured interface to the 'req.session' object,
+ * that is populated by the express-session middleware.
+ * @class ExpressStore
+ */
+export class ExpressStore<V extends string = StorageKeys>
+  extends SessionBase<V>
+  implements SessionManager<V>
+{
+  /**
+   * The Express req obj which holds the session's data
+   */
+  private req: Request;
+
+  constructor(req: Request) {
+    super();
+    if (!req.session) {
+      throw new Error(
+        "Session not available on the request. Please ensure the 'express-session' middleware is configured and running before the Kinde middleware.",
+      );
+    }
+    this.req = req;
+  }
+
+  /**
+   * Gets a value from the Express session.
+   * @param {string} itemKey
+   * @returns {Promise<unknown | null>}
+   */
+  async getSessionItem(itemKey: V | StorageKeys): Promise<unknown | null> {
+    // Reassemble split string values if present
+    const baseKey = `${storageSettings.keyPrefix}${String(itemKey)}`;
+    if (this.req.session![`${baseKey}0`] === undefined) {
+      return null;
+    }
+
+    // if under settingConfig maxLength - return as-is
+    if (this.req.session![`${baseKey}1`] === undefined) {
+      return this.req.session![`${baseKey}0`];
+    }
+
+    // Multiple items exist, concatenate them as strings (for split strings)
+    let itemValue = "";
+    let index = 0;
+    let key = `${baseKey}${index}`;
+    while (this.req.session![key] !== undefined) {
+      itemValue += this.req.session![key] as string;
+      index++;
+      key = `${baseKey}${index}`;
+    }
+    return itemValue;
+  }
+
+  /**
+   * Sets a value in the Express session.
+   * @param {string} itemKey
+   * @param {unknown} itemValue
+   * @returns {Promise<void>}
+   */
+  async setSessionItem(
+    itemKey: V | StorageKeys,
+    itemValue: unknown,
+  ): Promise<void> {
+    // Remove any existing split items first
+    await this.removeSessionItem(itemKey);
+    const baseKey = `${storageSettings.keyPrefix}${String(itemKey)}`;
+    if (typeof itemValue === "string") {
+      splitString(itemValue, storageSettings.maxLength).forEach(
+        (splitValue, index) => {
+          this.req.session![`${baseKey}${index}`] = splitValue;
+        },
+      );
+      return;
+    }
+    this.req.session![`${baseKey}0`] = itemValue;
+  }
+
+  /**
+   * Removes a value from the Express session.
+   * @param {string} itemKey
+   * @returns {Promise<void>}
+   */
+  async removeSessionItem(itemKey: V | StorageKeys): Promise<void> {
+    // Remove all items with the key prefix
+    const baseKey = `${storageSettings.keyPrefix}${String(itemKey)}`;
+    for (const key in this.req.session!) {
+      if (key.startsWith(baseKey)) {
+        delete this.req.session![key];
+      }
+    }
+  }
+
+  /**
+   * Clears the entire Express session.
+   * @returns {Promise<void>}
+   */
+  async destroySession(): Promise<void> {
+    return new Promise((resolve, reject) => {
+      this.req.session!.destroy((err) => {
+        if (err) {
+          return reject(err);
+        }
+        resolve();
+      });
+    });
+  }
+}

package.json

@@ -51,7 +51,8 @@
     "vite": "^6.0.0",
     "vite-plugin-dts": "^4.0.3",
     "vitest": "^3.0.0",
-    "vitest-fetch-mock": "^0.4.1"
+    "vitest-fetch-mock": "^0.4.1",
+    "@types/express": "^4.17.0"
   },
   "peerDependencies": {
     "expo-secure-store": ">=11.0.0"
@@ -65,4 +66,4 @@
   "dependencies": {
     "@kinde/jwt-decoder": "^0.2.0"
   }
-}
+}