feat: ✨ add local storage wrapper/impl

src/storage/storage-local-provider.service.ts

@@ -0,0 +1,80 @@
+import { Injectable } from '@nestjs/common';
+import { existsSync, mkdir, readFile, writeFile } from 'fs';
+
+const localPath = 'data/';
+
+/**
+ * Storage provider for local file system
+ * Uses the file system on the host machine
+ * to store and retrieve files
+ *
+ * @extends StorageProvider
+ */
+@Injectable()
+export class StorageLocalProviderService {
+  private isInitialized = false;
+
+  /**
+   * Initializes the local storage provider
+   * Creates the data directory if it does not exist
+   */
+  private initialize(): void {
+    if (!this.isInitialized && !existsSync(localPath)) {
+      mkdir(localPath, (err) => {
+        if (err)
+          console.error('Failed to initialize local storage provider: ', err);
+        else this.isInitialized = true;
+      });
+    }
+  }
+
+  /**
+   * Fetches a file from the local storage provider
+   *
+   * @param path the path to the file to fetch
+   * @returns if the file was fetched successfully, and the contents of the file
+   */
+  public async get(path: string): Promise<{ success: boolean; data: string }> {
+    this.initialize();
+
+    return new Promise((resolve, reject) => {
+      readFile(localPath + path, (err, data) => {
+        if (err) {
+          console.error(
+            'Failed to get file from local storage provider: ',
+            err,
+          );
+          reject({ success: false, data: null });
+        } else {
+          resolve({ success: true, data: data.toString() });
+        }
+      });
+    });
+  }
+
+  /**
+   * Sets a file in the local storage provider
+   *
+   * @param path the path to the file to set
+   * @param value the value to set the file to
+   * @returns true if the file was set successfully
+   */
+  public async set(path: string, value: any): Promise<boolean> {
+    this.initialize();
+
+    if (!existsSync(localPath + path)) {
+      return new Promise((resolve, reject) => {
+        reject('File does not exist');
+      });
+    }
+
+    return new Promise((resolve, reject) => {
+      writeFile(localPath + path, value, (err) => {
+        if (err) {
+          console.error('Failed to set file in local storage provider: ', err);
+          return reject(false);
+        } else resolve(true);
+      });
+    });
+  }
+}

src/storage/storage.module.ts

@@ -0,0 +1,11 @@
+import { Module } from '@nestjs/common';
+import { StorageProvider } from './storage.service';
+import { StorageLocalProviderService } from './storage-local-provider.service';
+
+@Module({
+  controllers: [],
+  providers: [
+    { provide: StorageProvider, useClass: StorageLocalProviderService },
+  ],
+})
+export class StorageModule {}

src/storage/storage.service.ts

@@ -0,0 +1,22 @@
+/**
+ * Abstract class for fetching files from a
+ * storage provider.
+ */
+export abstract class StorageProvider {
+  /**
+   * Fetches a file from the storage provider
+   * @param path the path to the file to fetch
+   *
+   * @returns contents of the file
+   */
+  abstract get(path: string): { success: boolean; data: any };
+
+  /**
+   * Sets a file in the storage provider
+   * @param path the path to the file to set
+   * @param value the value to set the file to
+   *
+   * @returns true if the file was set successfully
+   */
+  abstract set(path: string, value: any): boolean;
+}