webdav2localdisk

Map a WebDAV server to a local Windows drive that reports DRIVE_FIXED to GetDriveType() — masquerade remote WebDAV storage as a local fixed disk at the kernel volume-device level.

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Why?

Some Windows applications refuse to run on — or even list — "network" drives. They call GetDriveTypeW("X:\\") and bail out unless the answer is DRIVE_FIXED (3). Examples:

• Games that store profile/save data on a "local" drive
• Installers that won't install onto network paths
• Drive-indexing tools, sync clients, performance counters
• Backup software that skips DRIVE_REMOTE

Cloud WebDAV providers (your NAS, Nextcloud, Synology Drive's WebDAV, rclone serve webdav, …) are perfectly fine for this — if the volume isn't labeled as "remote". webdav2localdisk does exactly that labeling trick (see PRINCIPLE.md) and wires it to a working WebDAV client with a simple GUI.

Screenshot

┌─────────────────────────────────────────┐
│  webdav2localdisk          — □ ✕        │
├─────────────────────────────────────────┤
│  WebDAV Connection                      │
│  URL: [https://dav.example.com/dav    ] │
│  User: [alice          ] Pass: [*****] │
│  Drive: [W: (free) ▼]  Cache: [......] │
│        [ Mount ] [ Unmount ] [ Test  ]  │
│  Status: Mounted on W: (DRIVE_FIXED)    │
├─────────────────────────────────────────┤
│  [OK] W: mounted — DRIVE_FIXED.        │
│  GetDriveTypeW(W:\) == 3 (FIXED)       │
│  ✅  PASS — The trick works!            │
└─────────────────────────────────────────┘

Build

Requirements:

• Windows 10/11 x64
• CMake ≥ 3.21, Visual Studio 2022 (MSVC)
• Qt 6.7+ (Widgets module)
• WinFsp 2023+ (developer SDK + redistributable)

git clone https://github.com/BlueFang/webdav2localdisk.git
cd webdav2localdisk
cmake -B build -S .
cmake --build build --config Release

💡 GitHub Actions auto-builds each push — download a ready-to-run exe from the Actions tab under the latest Build (Windows) workflow artifact.

How it works (TL;DR)

The whole project hinges on one line in fs_driver.cpp:

StringCchCopyW(params.Prefix, ..., L"");   // empty = local-disk mode

When FspFileSystemCreate is called with an empty VolumePrefix, WinFsp takes its local-disk code path: the device object is created with DeviceType = FILE_DEVICE_DISK. GetDriveTypeW inspects that exact field and answers DRIVE_FIXED (3).

With any non-empty UNC prefix ("\\server\share"), WinFsp routes through MUP and the device becomes FILE_DEVICE_NETWORK_FILE_SYSTEM, answering DRIVE_REMOTE (4). That's what all standard WebDAV mounts produce — and exactly why this project exists.

Full walkthrough in docs/PRINCIPLE.md.

Status / Roadmap

• DRIVE_FIXED trick — VolumePrefix="" in fs_driver.cpp
• Full WebDAV implementation — PROPFIND / GET / PUT / MKCOL / MOVE / DELETE
• Qt GUI — fill form, mount/unmount, one-click GetDriveType test
• In-memory directory cache — avoids repeated PROPFIND calls
• GitHub Actions CI — auto-builds exe on push
• On-disk file cache (currently in-memory only)
• Digest / Bearer auth (currently Basic only)
• Inno Setup installer with WinFsp bundling
• CI x86 target

License

MIT — see LICENSE.