[msal-extensions] Extensions #2

extensions/src/error/PersistenceError.ts

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+/*
+ * Copyright (c) Microsoft Corporation. All rights reserved.
+ * Licensed under the MIT License.
+ */
+
+/**
+ * Error thrown when trying to write MSAL cache to persistence.
+ */
+export class PersistenceError extends Error {
+
+    // Short string denoting error
+    errorCode: string;
+    // Detailed description of error
+    errorMessage: string;
+
+    constructor(errorCode: string, errorMessage: string) {
+        const errorString = errorMessage ? `${errorCode}: ${errorMessage}` : errorCode;
+        super(errorString);
+        Object.setPrototypeOf(this, PersistenceError.prototype);
+
+        this.errorCode = errorCode;
+        this.errorMessage = errorMessage;
+        this.name = "PersistenceError";
+    }
+
+    static createFileSystemError(errorCode: string, errorMessage: string): PersistenceError {
+        return new PersistenceError(errorCode, errorMessage);
+    }
+
+    static createLibSecretError(errorCode: string, errorMessage: string): PersistenceError {
+        const updatedErrorMessage = `Error accessing Gnome Keyring: ${errorCode}- ${errorMessage}`;
+        return new PersistenceError("GnomeKeyringError", updatedErrorMessage);
+    }
+
+    static createKeychainPersistenceError(errorCode: string, errorMessage: string): PersistenceError {
+        const updatedErrorMessage = `Error accessing Keychain: ${errorCode}- ${errorMessage}`;
+        return new PersistenceError("KeychainError", updatedErrorMessage);
+    }
+
+    static createFilePersistenceWithDPAPIError(errorCode: string,errorMessage: string): PersistenceError {
+        const updatedErrorMessage = `Error accessing DPAPI encrypted file: ${errorCode}- ${errorMessage}`;
+        return new PersistenceError("DPAPIEncryptedFileError", updatedErrorMessage);
+    }
+
+    static createCrossPlatformLockError(errorCode: string, errorMessage: string): PersistenceError {
+        const updatedErrorMessage = `Error acquiring lock: ${errorCode}- ${errorMessage}`;
+        return new PersistenceError("CrossPlatformLockError", updatedErrorMessage);
+    }
+}

extensions/src/index.ts

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+export { PersistenceCachePlugin } from "./persistence/PersistenceCachePlugin"
+export { FilePersistence } from "./persistence/FilePersistence";
+export { FilePersistenceWithDataProtection } from "./persistence/FilePersistenceWithDataProtection";
+export { DataProtectionScope } from "./persistence/DataProtectionScope";
+export { KeychainPersistence } from "./persistence/KeychainPersistence";
+export { LibSecretPersistence } from "./persistence/LibSecretPersistence";
+export { IPersistence } from "./persistence/IPersistence";
+export { CrossPlatformLockOptions } from "./lock/CrossPlatformLockOptions";

extensions/src/lock/CrossPlatformLock.ts

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+/*
+ * Copyright (c) Microsoft Corporation. All rights reserved.
+ * Licensed under the MIT License.
+ */
+
+import { open, close, write, unlink } from "fs";
+import { promisify } from "util";
+import { pid } from "process";
+import { CrossPlatformLockOptions } from "./CrossPlatformLockOptions";
+import { Constants } from "../utils/Constants";
+import { PersistenceError } from "../error/PersistenceError";
+
+/**
+ * Cross-process lock that works on all platforms.
+ */
+export class CrossPlatformLock {
+
+    private readonly lockFilePath: string;
+    private lockFileDescriptor: number;
+    private readonly retryNumber: number;
+    private readonly retryDelay: number;
+
+    constructor(lockFilePath:string, lockOptions?: CrossPlatformLockOptions) {
+        this.lockFilePath = lockFilePath;
+        this.retryNumber = lockOptions ? lockOptions.retryNumber : 500;
+        this.retryDelay = lockOptions ? lockOptions.retryDelay : 100;
+    }
+
+    /**
+     * Locks cache from read or writes by creating file with same path and name as
+     * cache file but with .lockfile extension. If another process has already created
+     * the lockfile, will retry again based on configuration settings set by CrossPlatformLockOptions
+     */
+    public async lock(): Promise<void> {
+        const processId = pid.toString();
+        for (let tryCount = 0; tryCount < this.retryNumber; tryCount++)
+            try {
+                console.log("Pid " + pid + " trying to acquire lock");
+                const openPromise = promisify(open);
+                this.lockFileDescriptor = await openPromise(this.lockFilePath, "wx+");
+
+                console.log("Pid " + pid + " acquired lock");
+                const writePromise = promisify(write);
+                await writePromise(this.lockFileDescriptor, processId);
+                break;
+            } catch (err) {
+                if (err.code == Constants.EEXIST_ERROR) {
+                    console.log(err);
+                    await this.sleep(this.retryDelay);
+                } else {
+                    throw PersistenceError.createCrossPlatformLockError(err.code, err.message);
+                }
+            }
+    }
+
+    /**
+     * unlocks cache file by deleting .lockfile.
+     */
+    public async unlock(): Promise<void> {
+        try {
+            // delete lock file
+            const unlinkPromise = promisify(unlink);
+            await unlinkPromise(this.lockFilePath);
+            const closePromise = promisify(close);
+            await closePromise(this.lockFileDescriptor);
+        } catch(err){
+            if(err.code == Constants.ENOENT_ERROR){
+                console.log("Lockfile does not exist");
+            } else {
+                throw PersistenceError.createCrossPlatformLockError(err.code, err.message);
+            }
+        }
+    }
+
+    private sleep(ms): Promise<void> {
+        return new Promise((resolve) => {
+            setTimeout(resolve, ms);
+        });
+    }
+}

extensions/src/lock/CrossPlatformLockOptions.ts

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+/*
+ * Copyright (c) Microsoft Corporation. All rights reserved.
+ * Licensed under the MIT License.
+ */
+
+/**
+ * Options for CrossPlatform lock.
+ *
+ * retryNumber: Numbers of times we should try to acquire a lock. Defaults to 500.
+ * retryDelay: Time to wait before trying to retry a lock acquisition. Defaults to 100 ms.
+ */
+export type CrossPlatformLockOptions = {
+    retryNumber: number;
+    retryDelay: number;
+}

extensions/src/utils/Constants.ts

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+/*
+ * Copyright (c) Microsoft Corporation. All rights reserved.
+ * Licensed under the MIT License.
+ */
+
+export const Constants = {
+
+    /**
+     * An existing file was the target of an operation that required that the target not exist
+     */
+    EEXIST_ERROR: "EEXIST",
+
+    /**
+     * No such file or directory: Commonly raised by fs operations to indicate that a component
+     * of the specified pathname does not exist. No entity (file or directory) could be found
+     * by the given path
+     */
+    ENOENT_ERROR: "ENOENT",
+
+    /**
+     * Default service name for using MSAL Keytar
+     */
+    DEFAULT_SERVICE_NAME: "msal-node-extensions",
+};