When a category's download path option is set to "Default", its `downloadPath` is serialized into JSON as `undefined`. This results in the `downloadPath` field being omitted from `torrents/categories` and `torrents/maindata` payloads (as is expected with an `undefined` value).
The use of `undefined` here causes an issue in the WebUI. Specifically, when the category previously contained a value for this field (i.e. download path option set to either "Yes" or "No"), the `processMap` logic in `SyncController` does not detect the removal this field. This results in the category's new `downloadPath` not being properly sent to the client. By switching from `undefined` to `null`, we ensure that the `downloadPath` value is always included in the category's payload. This allows `processMap` to properly detect whenever the value changes.
This change is backwards compatible with existing categories.json files. Older qBittorrent versions should also be able to parse new categories.json files containing `null`.
More context: cd3fbfbf9b (r2173148696)
PR #22958.
## Description
Send file/folder metadata instead of just the name of a filesystem entry.
Currently the endpoint only sends a list of string, containing the path of each entry, without specifying its type (file or folder).
The optional `withMetadata` flag has been added to provide metadata and to prevent breaking changes with older versions.
If `true`, JSON response will be an array of objects instead of an array of strings.
This object contains:
- `name`: the name of the file system entry (without path)
- `type`: Whether the file system entry is a "file" or a "dir"
- `creation_date`: file system entry's creation date
- `last_access_date`: file system entry's last access date
- `last_modification_date`: file system entry's last modification date
If the entry is a file, a `size` field is present with the file size in bytes.
## Objective
Build a server file browser inside WebUIs, feature is currently being developed for VueTorrent.
It will include file metadata, filtering and sorting on the different fields.
PR #22813.
