fix: Should correctly handle range download n+1 issue

Author: ci010

packages/file-transfer/agent.ts

@@ -104,7 +104,7 @@ export class DownloadAgent {
         const { contentLength, isAcceptRanges } = parseRangeInfo(response.headers)
         ranges = contentLength && isAcceptRanges
           ? this.rangePolicy.computeRanges(contentLength)
-          : [{ start: 0, end: contentLength }]
+          : [{ start: 0, end: contentLength - 1 }]
         targetUrl = new URL(location)
         total = contentLength
         await handle.truncate(total)

packages/file-transfer/range.ts

@@ -56,6 +56,10 @@ export async function * range(
 
   let nextUrl = url
   while (true) {
+    if (segment.start >= segment.end) {
+      // the segment is finished, just ignore it
+      return
+    }
     try {
       const { opaque } = await stream(nextUrl, {
         method: 'GET',
@@ -84,7 +88,10 @@ export async function * range(
         }
         if (typeof responseHeaders['content-length'] === 'string') {
           contentLength = Number.parseInt(responseHeaders['content-length'] ?? '0')
-          segment.end = contentLength
+          const end = segment.start + contentLength - 1
+          if (end !== segment.end) {
+            segment.end = segment.start + contentLength
+          }
         }
         return (opaque as any).fileStream as Writable
       })