Fix Real-Debrid resume size mismatch handling

src/main/download-manager.ts

@@ -118,6 +118,8 @@ const ARCHIVE_SETTLE_MAX_WAIT_MS = 5000;
 
 const MAX_SAME_DIRECT_URL_ATTEMPTS = 3;
 
+const REALDEBRID_TOTAL_MISMATCH_TOLERANCE_BYTES = 64 * 1024;
+
 const LARGE_BINARY_FILE_RE = /\.(?:part\d+\.rar|rar|r\d{2,3}|zip(?:\.\d+)?|7z(?:\.\d+)?|tar|gz|bz2|xz|iso|mkv|mp4|avi|mov|wmv|m4v|ts|m2ts|webm|mp3|flac|aac|wav)$/i;
 
 function itemExpectedMinBytes(item: DownloadItem): number {
@@ -412,6 +414,67 @@ function isResumeHardResetReason(errorText: string): boolean {
   return text.startsWith("resume_download_underflow:");
 }
 
+function isRealDebridProvider(provider: string | null | undefined): boolean {
+  return String(provider || "").trim().toLowerCase() === "realdebrid";
+}
+
+export function getAuthoritativeRealDebridTotal(
+  provider: string | null | undefined,
+  knownTotal: number,
+  existingBytes: number,
+  responseStatus: number,
+  contentLength: number,
+  totalFromRange: number | null,
+  resumeHardResetUsed: boolean
+): { totalBytes: number; source: "content-range" | "content-length"; mismatchBytes: number } | null {
+  if (!isRealDebridProvider(provider) || !knownTotal || knownTotal <= 0) {
+    return null;
+  }
+
+  const evaluateCandidate = (
+    candidateTotal: number,
+    source: "content-range" | "content-length"
+  ): { totalBytes: number; source: "content-range" | "content-length"; mismatchBytes: number } | null => {
+    if (!Number.isFinite(candidateTotal) || candidateTotal <= 0 || candidateTotal >= knownTotal) {
+      return null;
+    }
+
+    const mismatchBytes = knownTotal - candidateTotal;
+    if (mismatchBytes > REALDEBRID_TOTAL_MISMATCH_TOLERANCE_BYTES) {
+      return null;
+    }
+
+    if (candidateTotal + ALLOCATION_UNIT_SIZE < existingBytes) {
+      return null;
+    }
+
+    if (responseStatus === 206) {
+      if (existingBytes <= 0) {
+        return null;
+      }
+      const maxReachableBytes = existingBytes + Math.max(0, contentLength);
+      if (candidateTotal > maxReachableBytes + ALLOCATION_UNIT_SIZE) {
+        return null;
+      }
+    } else if (responseStatus === 200) {
+      if (!resumeHardResetUsed || source !== "content-length") {
+        return null;
+      }
+    } else {
+      return null;
+    }
+
+    return {
+      totalBytes: candidateTotal,
+      source,
+      mismatchBytes
+    };
+  };
+
+  return evaluateCandidate(totalFromRange || 0, "content-range")
+    || evaluateCandidate(contentLength, "content-length");
+}
+
 function isPermanentLinkError(errorText: string): boolean {
   const text = String(errorText || "").toLowerCase();
   return text.includes("permanent ungültig")
@@ -6755,9 +6818,10 @@ export class DownloadManager extends EventEmitter {
               active.resumeHardResetUsed = true;
               item.retries += 1;
               logger.warn(`Resume-Neustart: item=${item.fileName || item.id}, error=${exhaustedReason}, provider=${item.provider || "?"}`);
-              if (claimedTargetPath) {
+              const resetTargetPath = claimedTargetPath || String(item.targetPath || "").trim();
+              if (resetTargetPath) {
                 try {
-                  fs.rmSync(claimedTargetPath, { force: true });
+                  fs.rmSync(resetTargetPath, { force: true });
                 } catch {
                   // ignore
                 }
@@ -7219,7 +7283,10 @@ export class DownloadManager extends EventEmitter {
         const contentLength = Number.isFinite(rawContentLength) && rawContentLength > 0 ? rawContentLength : 0;
         const totalFromRange = parseContentRangeTotal(response.headers.get("content-range"));
         const serverIgnoredRange = existingBytes > 0 && response.status === 200;
-        if (serverIgnoredRange) {
+        const allowFreshOverwriteAfterResumeReset = serverIgnoredRange
+          && active.resumeHardResetUsed
+          && isRealDebridProvider(item.provider);
+        if (serverIgnoredRange && !allowFreshOverwriteAfterResumeReset) {
           logger.warn(`Server ignorierte Range-Header (HTTP 200 statt 206), verwerfe Direktlink und behalte Teil-Datei: ${item.fileName}`);
           logAttemptEvent("WARN", "Server ignorierte Range-Header beim Resume", {
             attempt,
@@ -7234,8 +7301,45 @@ export class DownloadManager extends EventEmitter {
           }
           throw new Error(`range_ignored_on_resume:${existingBytes}/${contentLength || 0}`);
         }
+        if (allowFreshOverwriteAfterResumeReset) {
+          logger.warn(
+            `Server ignorierte Range-Header nach Resume-Reset, ueberschreibe alte Teil-Datei frisch: ${item.fileName}`
+          );
+          logAttemptEvent("WARN", "Range ignoriert nach Resume-Reset, frischer Vollstart erlaubt", {
+            attempt,
+            existingBytes,
+            contentLength,
+            directUrl
+          });
+        }
 
-        if (knownTotal && knownTotal > 0) {
+        const correctedRealDebridTotal = getAuthoritativeRealDebridTotal(
+          item.provider,
+          knownTotal || 0,
+          existingBytes,
+          response.status,
+          contentLength,
+          totalFromRange,
+          Boolean(active.resumeHardResetUsed)
+        );
+        if (correctedRealDebridTotal) {
+          item.totalBytes = correctedRealDebridTotal.totalBytes;
+          logger.warn(
+            `Real-Debrid-Zielgroesse korrigiert: ${item.fileName} ` +
+            `known=${knownTotal}, corrected=${correctedRealDebridTotal.totalBytes}, ` +
+            `source=${correctedRealDebridTotal.source}`
+          );
+          logAttemptEvent("WARN", "Real-Debrid-Zielgroesse aus HTTP korrigiert", {
+            attempt,
+            source: correctedRealDebridTotal.source,
+            knownTotal,
+            correctedTotal: correctedRealDebridTotal.totalBytes,
+            mismatchBytes: correctedRealDebridTotal.mismatchBytes,
+            existingBytes,
+            contentLength,
+            totalFromRange
+          });
+        } else if (knownTotal && knownTotal > 0) {
           item.totalBytes = knownTotal;
         } else if (totalFromRange) {
           item.totalBytes = totalFromRange;

src/renderer/App.tsx

@@ -3805,7 +3805,7 @@ export function App(): ReactElement {
             <svg viewBox="0 0 24 24" width="16" height="16"><path d="M12 20l7-7h-4.5V4h-5v9H5z" fill="currentColor" /></svg>
           </button>
         </div>
-        {snapshot.reconnectSeconds > 0 && (
+        {snapshot.reconnectSeconds > 0 && tab !== "downloads" && (
           <div className="reconnect-badge" style={{ marginLeft: "auto" }}>Reconnect: {snapshot.reconnectSeconds}s</div>
         )}
       </section>

tests/download-manager.test.ts

@@ -5,7 +5,7 @@ import http from "node:http";
 import { EventEmitter, once } from "node:events";
 import AdmZip from "adm-zip";
 import { afterEach, describe, expect, it } from "vitest";
-import { DownloadManager } from "../src/main/download-manager";
+import { DownloadManager, getAuthoritativeRealDebridTotal } from "../src/main/download-manager";
 import { defaultSettings } from "../src/main/constants";
 import { parseDebridLinkApiKeys } from "../src/shared/debrid-link-keys";
 import { getProviderUsageDayKey } from "../src/shared/provider-daily-limits";
@@ -475,6 +475,187 @@ describe("download manager", () => {
     }
   });
 
+  it("treats tiny Real-Debrid resume size mismatches as completed instead of looping", async () => {
+    const root = fs.mkdtempSync(path.join(os.tmpdir(), "rd-dm-"));
+    tempDirs.push(root);
+    const actual = Buffer.alloc(192 * 1024, 17);
+    const advertisedSize = actual.length + 5000;
+    const pkgDir = path.join(root, "downloads", "rd-mismatch");
+    fs.mkdirSync(pkgDir, { recursive: true });
+    const existingTargetPath = path.join(pkgDir, "rd-mismatch.part01.rar");
+    fs.writeFileSync(existingTargetPath, actual);
+
+    let unrestrictCalls = 0;
+    let resumeCalls = 0;
+    const resumeStarts: number[] = [];
+
+    const server = http.createServer((req, res) => {
+      if ((req.url || "") !== "/rd-mismatch") {
+        res.statusCode = 404;
+        res.end("not-found");
+        return;
+      }
+
+      resumeCalls += 1;
+      const range = String(req.headers.range || "");
+      const match = range.match(/bytes=(\d+)-/i);
+      const start = match ? Number(match[1]) : 0;
+      resumeStarts.push(start);
+
+      if (start >= actual.length) {
+        res.statusCode = 206;
+        res.setHeader("Accept-Ranges", "bytes");
+        res.setHeader("Content-Range", `bytes 0-${actual.length - 1}/${actual.length}`);
+        res.setHeader("Content-Length", "0");
+        res.end();
+        return;
+      }
+
+      const chunk = actual.subarray(start);
+      if (start > 0) {
+        res.statusCode = 206;
+        res.setHeader("Content-Range", `bytes ${start}-${actual.length - 1}/${actual.length}`);
+      } else {
+        res.statusCode = 200;
+      }
+      res.setHeader("Accept-Ranges", "bytes");
+      res.setHeader("Content-Length", String(chunk.length));
+      res.end(chunk);
+    });
+
+    server.listen(0, "127.0.0.1");
+    await once(server, "listening");
+
+    const address = server.address();
+    if (!address || typeof address === "string") {
+      throw new Error("server address unavailable");
+    }
+    const directUrl = `http://127.0.0.1:${address.port}/rd-mismatch`;
+
+    globalThis.fetch = async (input: RequestInfo | URL, init?: RequestInit): Promise<Response> => {
+      const url = typeof input === "string" ? input : input instanceof URL ? input.toString() : input.url;
+      if (url.includes("/unrestrict/link")) {
+        unrestrictCalls += 1;
+        return new Response(
+          JSON.stringify({
+            download: directUrl,
+            filename: "rd-mismatch.part01.rar",
+            filesize: advertisedSize
+          }),
+          {
+            status: 200,
+            headers: { "Content-Type": "application/json" }
+          }
+        );
+      }
+      return originalFetch(input, init);
+    };
+
+    try {
+      const session = emptySession();
+      const packageId = "rd-mismatch-pkg";
+      const itemId = "rd-mismatch-item";
+      const createdAt = Date.now() - 10_000;
+
+      session.packageOrder = [packageId];
+      session.packages[packageId] = {
+        id: packageId,
+        name: "rd-mismatch",
+        outputDir: pkgDir,
+        extractDir: path.join(root, "extract", "rd-mismatch"),
+        status: "queued",
+        itemIds: [itemId],
+        cancelled: false,
+        enabled: true,
+        createdAt,
+        updatedAt: createdAt
+      };
+      session.items[itemId] = {
+        id: itemId,
+        packageId,
+        url: "https://dummy/rd-mismatch",
+        provider: "realdebrid",
+        status: "queued",
+        retries: 0,
+        speedBps: 0,
+        downloadedBytes: actual.length,
+        totalBytes: advertisedSize,
+        progressPercent: Math.floor((actual.length / advertisedSize) * 100),
+        fileName: "rd-mismatch.part01.rar",
+        targetPath: existingTargetPath,
+        resumable: true,
+        attempts: 0,
+        lastError: "",
+        fullStatus: "Wartet",
+        createdAt,
+        updatedAt: createdAt
+      };
+
+      const manager = new DownloadManager(
+        {
+          ...defaultSettings(),
+          token: "rd-token",
+          outputDir: path.join(root, "downloads"),
+          extractDir: path.join(root, "extract"),
+          retryLimit: 1,
+          autoExtract: false,
+          autoReconnect: false
+        },
+        session,
+        createStoragePaths(path.join(root, "state"))
+      );
+
+      await manager.start();
+      await waitFor(() => !manager.getSnapshot().session.running, 12000);
+
+      const item = manager.getSnapshot().session.items[itemId];
+      expect(item?.status).toBe("completed");
+      expect(item?.downloadedBytes).toBe(actual.length);
+      expect(item?.totalBytes).toBe(actual.length);
+      expect(unrestrictCalls).toBe(1);
+      expect(resumeCalls).toBeGreaterThanOrEqual(1);
+      expect(resumeStarts).toContain(actual.length);
+      expect(fs.statSync(existingTargetPath).size).toBe(actual.length);
+    } finally {
+      server.close();
+      await once(server, "close");
+    }
+  });
+
+  it("accepts the smaller Real-Debrid full response after a resume hard reset", () => {
+    const actualSize = 224 * 1024;
+    const advertisedSize = actualSize + 5000;
+    const partialSize = actualSize - 48 * 1024;
+
+    expect(
+      getAuthoritativeRealDebridTotal(
+        "realdebrid",
+        advertisedSize,
+        partialSize,
+        200,
+        actualSize,
+        null,
+        true
+      )
+    ).toEqual({
+      totalBytes: actualSize,
+      source: "content-length",
+      mismatchBytes: 5000
+    });
+
+    expect(
+      getAuthoritativeRealDebridTotal(
+        "realdebrid",
+        advertisedSize,
+        partialSize,
+        200,
+        actualSize,
+        null,
+        false
+      )
+    ).toBeNull();
+  });
+
   it("does not renew direct links when the file is already complete on disk", async () => {
     const root = fs.mkdtempSync(path.join(os.tmpdir(), "rd-dm-"));
     tempDirs.push(root);