Added machine learning microservice and object detection (#76)

microservices/src/object-detection/object-detection.controller.ts

@@ -0,0 +1,14 @@
+import { Body, Controller, Post } from '@nestjs/common';
+import { ObjectDetectionService } from './object-detection.service';
+
+@Controller('object-detection')
+export class ObjectDetectionController {
+  constructor(
+    private readonly objectDetectionService: ObjectDetectionService,
+  ) {}
+
+  @Post('/detectObject')
+  async detectObject(@Body('thumbnailPath') thumbnailPath: string) {
+    return await this.objectDetectionService.detectObject(thumbnailPath);
+  }
+}

microservices/src/object-detection/object-detection.module.ts

@@ -0,0 +1,9 @@
+import { Module } from '@nestjs/common';
+import { ObjectDetectionService } from './object-detection.service';
+import { ObjectDetectionController } from './object-detection.controller';
+
+@Module({
+  controllers: [ObjectDetectionController],
+  providers: [ObjectDetectionService],
+})
+export class ObjectDetectionModule {}

microservices/src/object-detection/object-detection.service.ts

@@ -0,0 +1,38 @@
+import { Injectable, Logger } from '@nestjs/common';
+import * as cocoSsd from '@tensorflow-models/coco-ssd';
+import * as tf from '@tensorflow/tfjs-node';
+import * as fs from 'fs';
+
+@Injectable()
+export class ObjectDetectionService {
+  private cocoSsdModel: cocoSsd.ObjectDetection;
+
+  constructor() {
+    Logger.log(
+      `Running Node TensorFlow Version : ${tf.version['tfjs']}`,
+      'ObjectDetection',
+    );
+    cocoSsd.load().then((model) => (this.cocoSsdModel = model));
+  }
+  async detectObject(thumbnailPath: string) {
+    try {
+      const isExist = fs.existsSync(thumbnailPath);
+      if (isExist) {
+        const tags = new Set();
+        const image = fs.readFileSync(thumbnailPath);
+        const decodedImage = tf.node.decodeImage(image, 3) as tf.Tensor3D;
+        const predictions = await this.cocoSsdModel.detect(decodedImage);
+
+        for (const result of predictions) {
+          if (result.score > 0.5) {
+            tags.add(result.class);
+          }
+        }
+
+        return [...tags];
+      }
+    } catch (e) {
+      console.log('Error reading file ', e);
+    }
+  }
+}