Improve backend media readiness for mobile clients

src/infrastructure/storage/managed-storage.service.ts

@@ -8,7 +8,8 @@ import {
 } from '@aws-sdk/client-s3';
 import { Upload } from '@aws-sdk/lib-storage';
 import { randomUUID } from 'crypto';
-import { mkdir, rm, unlink, writeFile } from 'fs/promises';
+import { constants } from 'fs';
+import { access, mkdir, rm, unlink, writeFile } from 'fs/promises';
 import { dirname, join, posix } from 'path';
 
 @Injectable()
@@ -182,6 +183,53 @@ export class ManagedStorageService implements OnModuleDestroy {
     await rm(join(process.cwd(), ...directoryPath.split('/')), { recursive: true, force: true });
   }
 
+  async getHealth(): Promise<Record<string, unknown>> {
+    const provider = this.getProvider();
+    const basePath = this.getBasePath();
+    const publicBaseUrl =
+      (this.configService.get<string>('storage.publicBaseUrl', { infer: true }) ?? '').replace(
+        /\/$/,
+        '',
+      );
+    const health: Record<string, unknown> = {
+      provider,
+      basePath,
+      publicPath: `/${basePath}`,
+      publicBaseUrlConfigured: !!publicBaseUrl,
+      s3Configured: provider === 's3' ? this.hasS3Configuration() : undefined,
+    };
+
+    if (provider === 'local') {
+      const uploadDir = join(process.cwd(), ...basePath.split('/'));
+      const probePath = join(uploadDir, `.media-health-${randomUUID()}.tmp`);
+      let writable = false;
+      let error = '';
+
+      try {
+        await mkdir(uploadDir, { recursive: true });
+        await writeFile(probePath, 'ok');
+        await unlink(probePath);
+        writable = true;
+      } catch (probeError) {
+        error = probeError instanceof Error ? probeError.message : 'unknown local storage error';
+        try {
+          await unlink(probePath);
+        } catch {
+          // Ignore cleanup failure for a failed probe.
+        }
+      }
+
+      health.local = {
+        runtimePath: uploadDir,
+        writable,
+        readable: await this.canAccess(uploadDir, constants.R_OK),
+        error,
+      };
+    }
+
+    return health;
+  }
+
   onModuleDestroy(): void {
     this.s3Client = null;
   }
@@ -323,6 +371,24 @@ export class ManagedStorageService implements OnModuleDestroy {
     return null;
   }
 
+  private hasS3Configuration(): boolean {
+    return !!(
+      (this.configService.get<string>('storage.s3.bucket', { infer: true }) ?? '') &&
+      (this.configService.get<string>('storage.s3.endpoint', { infer: true }) ?? '') &&
+      (this.configService.get<string>('storage.s3.accessKeyId', { infer: true }) ?? '') &&
+      (this.configService.get<string>('storage.s3.secretAccessKey', { infer: true }) ?? '')
+    );
+  }
+
+  private async canAccess(path: string, mode: number): Promise<boolean> {
+    try {
+      await access(path, mode);
+      return true;
+    } catch {
+      return false;
+    }
+  }
+
   private async deleteS3Prefix(prefix: string): Promise<void> {
     const client = this.getS3Client();
     const bucket = this.getS3Bucket();