Carry files and drag data transfers in event payloads - #26
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`form-data` gains `files: list<own<file>>`, and drag events move from the
`mouse` family to `drag-data { mouse, transfer: option<own<data-transfer>> }`.
Both new types are host resources, for reasons the DOM dictates: a File's
contents are only readable asynchronously (so `file.read` returns a
`stream<u8>`, the shape `eval` already uses), and a DataTransfer's setters
mean something only against the live object during `dragstart`, while
protected mode hides `getData` outside `dragstart`/`drop` — a snapshot
would have to fake both. This is what dioxus-web's users already see.
Guest: `WitFile` / `WitDataTransfer` back dioxus-html's `NativeFileData`
and `NativeDataTransfer` one to one. Owned handles are lifted out of the
payload once at `WitEventData` construction, since dioxus may convert the
same dispatch more than once and a handle moves only once. `byte_stream`
is `unfold` over chunked reads, yielding a final chunk that arrives with
`Dropped`; the `Send` bounds are satisfied the way dioxus-web satisfies
them, by assertion on a single-threaded target.
Host: `HostFile` wraps a `File` (metadata as bigint where the WIT says
u64; `read` returns `File.stream()`), `HostDataTransfer` wraps the live
DataTransfer and reports refused setters as `ComponentException`. Both
register under the `events` import beside `DomEvent`; instances nested in
a payload passed to `handle-event` register on the way through, as the
contract says.
The other families that still dispatch as `empty` — clipboard, media,
selection, toggle — carry nothing because dioxus-html's own data types
for them expose no accessors; there is nothing to add.
lannbot
enabled auto-merge
September 5, 2026 13:37
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Closes the last event-payload gap against dioxus-web.
WIT (
interface events):form-data.files: list<own<file>>; newpayload.drag(drag-data { mouse, transfer: option<own<data-transfer>> })replacing the mouse-family reuse for drag names;resource file(name/size/last-modified/content-type,read() -> stream<u8>);resource data-transfermirroringNativeDataTransferone to one.Both are resources rather than snapshots because the DOM makes them so: File contents read asynchronously; DataTransfer setters only work live during
dragstart, and protected mode hidesgetDataoutsidedragstart/drop.Guest:
WitFile/WitDataTransfer; handles lifted once atWitEventDataconstruction (dioxus may convert a dispatch more than once);byte_streamviaunfoldover chunked reads; Send bounds asserted as dioxus-web does.Host:
HostFile(readreturnsFile.stream(), verified end-to-end through the runtime),HostDataTransfer(refused setters →ComponentException), registered undereventswithDomEvent.Tests: unit tests for both classes and the payload shapes; platform-probe fixture gains a file input and a drop target — e2e asserts
read_stringandbyte_streamagree on a realFile, and that a guestset_dataindragstartis read back ondrop. 151 deno tests; fulljustgate set passes.Clipboard/media/selection/toggle remain
empty: dioxus-html's data types for them have no accessors.Automerge armed (merge commit).