@uppy/aws-s3: resolve all headers on response (#5195)

Co-authored-by: Antoine du Hamel <antoine@transloadit.com>

packages/@uppy/aws-s3-multipart/src/index.test.ts

@@ -91,6 +91,7 @@ describe('AwsS3Multipart', () => {
       expect(uploadSuccessHandler.mock.calls[0][1]).toStrictEqual({
         body: {
           ETag: 'test',
+          etag: 'test',
           location: 'http://example.com',
         },
         status: 200,
@@ -257,16 +258,16 @@ describe('AwsS3Multipart', () => {
         .mock.calls[0][1]
 
       expect(completeCall.parts).toEqual([
-        { ETag: 'test', PartNumber: 1 },
-        { ETag: 'test', PartNumber: 2 },
-        { ETag: 'test', PartNumber: 3 },
-        { ETag: 'test', PartNumber: 4 },
-        { ETag: 'test', PartNumber: 5 },
-        { ETag: 'test', PartNumber: 6 },
-        { ETag: 'test', PartNumber: 7 },
-        { ETag: 'test', PartNumber: 8 },
-        { ETag: 'test', PartNumber: 9 },
-        { ETag: 'test', PartNumber: 10 },
+        { ETag: 'test', etag: 'test', PartNumber: 1 },
+        { ETag: 'test', etag: 'test', PartNumber: 2 },
+        { ETag: 'test', etag: 'test', PartNumber: 3 },
+        { ETag: 'test', etag: 'test', PartNumber: 4 },
+        { ETag: 'test', etag: 'test', PartNumber: 5 },
+        { ETag: 'test', etag: 'test', PartNumber: 6 },
+        { ETag: 'test', etag: 'test', PartNumber: 7 },
+        { ETag: 'test', etag: 'test', PartNumber: 8 },
+        { ETag: 'test', etag: 'test', PartNumber: 9 },
+        { ETag: 'test', etag: 'test', PartNumber: 10 },
       ])
     })
 

packages/@uppy/aws-s3-multipart/src/index.ts

@@ -726,7 +726,7 @@ export default class AwsS3Multipart<
         ;(error as any).source = { status: 403 }
         reject(error)
       })
-      xhr.addEventListener('load', (ev) => {
+      xhr.addEventListener('load', () => {
         cleanup()
 
         if (
@@ -748,9 +748,20 @@ export default class AwsS3Multipart<
         // todo make a proper onProgress API (breaking change)
         onProgress?.({ loaded: size, lengthComputable: true })
 
-        // NOTE This must be allowed by CORS.
-        const etag = xhr.getResponseHeader('ETag')
-        const location = xhr.getResponseHeader('Location')
+        // https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/getAllResponseHeaders#examples
+        const arr = xhr
+          .getAllResponseHeaders()
+          .trim()
+          .split(/[\r\n]+/)
+        // @ts-expect-error null is allowed to avoid inherited properties
+        const headersMap: Record<string, string> = { __proto__: null }
+        for (const line of arr) {
+          const parts = line.split(': ')
+          const header = parts.shift()!
+          const value = parts.join(': ')
+          headersMap[header] = value
+        }
+        const { etag, location } = headersMap
 
         if (method.toUpperCase() === 'POST' && location === null) {
           // Not being able to read the Location header is not a fatal error.
@@ -770,8 +781,8 @@ export default class AwsS3Multipart<
 
         onComplete?.(etag)
         resolve({
-          ETag: etag,
-          ...(location ? { location } : undefined),
+          ...headersMap,
+          ETag: etag, // keep capitalised ETag for backwards compatiblity
         })
       })