allow files to display on frontend (#150)

Co-authored-by: Anson He <[email protected]>

backend/aws/s3.js

@@ -1,4 +1,16 @@
-const { S3Client, DeleteObjectCommand } = require('@aws-sdk/client-s3')
+const {
+    S3Client,
+    DeleteObjectCommand,
+    GetObjectCommand,
+} = require('@aws-sdk/client-s3')
+const { getSignedUrl } = require('@aws-sdk/s3-request-presigner')
+
+const { HttpRequest } = require('@aws-sdk/protocol-http')
+const { formatUrl } = require('@aws-sdk/util-format-url')
+
+const { S3RequestPresigner } = require('@aws-sdk/s3-request-presigner')
+const { Hash } = require('@aws-sdk/hash-node')
+
 const s3Client = new S3Client({
     region: 'us-east-2',
 })
@@ -16,8 +28,17 @@ const deleteS3File = (bucket, key) => {
     return s3Client.send(deleteCommand)
 }
 
+const generatePresignedUrl = async (bucket, key) => {
+    const command = new GetObjectCommand({
+        Bucket: bucket,
+        Key: key,
+    })
+    return getSignedUrl(s3Client, command, { expiresIn: 60 * 60 })
+}
+
 module.exports = {
     s3Client,
     getS3FileKey,
     deleteS3File,
+    generatePresignedUrl,
 }

backend/package.json

@@ -12,6 +12,7 @@
     "dependencies": {
         "@aws-sdk/client-s3": "^3.370.0",
         "@aws-sdk/lib-storage": "^3.370.0",
+        "@aws-sdk/s3-request-presigner": "^3.374.0",
         "aws-sdk": "^2.1416.0",
         "axios": "^1.2.3",
         "cors": "^2.8.5",

backend/service/files.service.js

@@ -1,12 +1,29 @@
 const File = require('../models/file.model')
-const { getS3FileKey, deleteS3File } = require('../aws/s3')
+const {
+    getS3FileKey,
+    deleteS3File,
+    generatePresignedUrl,
+} = require('../aws/s3')
 
 const getFile = async (id) => {
     return File.findById(id)
 }
 
 const getAllFilesByReference = async (reference) => {
-    return File.find({ reference_code: reference })
+    const files = await File.find({ reference_code: reference })
+    return Promise.all(
+        files.map(async (file) => {
+            // generate a presigned url for each file
+            const presignedUrl = await generatePresignedUrl(
+                process.env.AWS_FINANCE_BUCKET_NAME,
+                getS3FileKey(file.reference_code, file.name)
+            )
+            return {
+                ...file.toObject(),
+                link: presignedUrl,
+            }
+        })
+    )
 }
 
 const createFile = async (file, referenceCode, isSupportingDocument) => {