feat: Adding load-attachments endpoints

sections/public-load-attachments/routes.js

@@ -0,0 +1,7 @@
+'use strict';
+const router = require('express').Router();
+const services= require('./services.js');
+
+router.get('/download/:id', services.getAttachmentFile );
+
+module.exports = router;

sections/public-load-attachments/services.js

@@ -0,0 +1,38 @@
+"use strict";
+const { ROOT_PATH, LIB_PATH, MODELS_PATH, API_CONFIG } = process.env;
+const apiConfig = require( `${ROOT_PATH}/${API_CONFIG}` );
+
+const { S3Client, GetObjectCommand } = require('@aws-sdk/client-s3');
+const s3Client = new S3Client({
+    region : apiConfig.S3.region,
+    credentials : {
+        accessKeyId : apiConfig.S3.accessKeyId,
+        secretAccessKey : apiConfig.S3.secretAccessKey
+    }
+});
+const s3Bucket = apiConfig.S3.bucket;
+const s3BucketKey = apiConfig.S3.key;
+
+async function downloadFile( bucket, key, obj_id ){
+    const params = {
+        Bucket: bucket,
+		Key : `${key}/${obj_id}`
+    };
+    const s3resp = await s3Client.send( new GetObjectCommand( params ) );
+    const chunks = []
+    for await (const chunk of s3resp.Body) {
+      chunks.push(chunk)
+    }
+    const body = Buffer.concat(chunks);
+    s3resp.Body = body;
+    return s3resp;
+}
+const getAttachmentFile = async(req, res) => {
+    const attachmentId = req.params.id;
+    const file = await downloadFile( s3Bucket, s3BucketKey, attachmentId );
+    res.attachment( attachmentId );
+    res.setHeader('Content-Type', file.ContentType );
+    res.send( file.Body );
+}
+
+module.exports = { getAttachmentFile };