Files
react/packages/react-server/src/ReactServerStreamConfigBun.js
Sebastian Markbåge ea05b750a5 Allow Passing Blob/File/MediaSource/MediaStream to src of <img>, <video> and <audio> (#32828)
Behind the `enableSrcObject` flag. This is revisiting a variant of what
was discussed in #11163.

Instead of supporting the [`srcObject`
property](https://developer.mozilla.org/en-US/docs/Web/API/HTMLMediaElement/srcObject)
as a separate name, this adds an overload of `src` to allow objects to
be passed. The DOM needs to add separate properties for the object forms
since you read back but it doesn't make sense for React's write-only API
to do that. Similar to how we'll like add an overload for
`popoverTarget` instead of calling it `popoverTargetElement` and how
`style` accepts an object and it's not `styleObject={{...}}`.

There are a number of reason to revisit this.

- It's just way more convenient to have this built-in and it makes
conceptual sense. We typically support declarative APIs and polyfill
them when necessary.
- RSC supports Blobs and by having it built-in you don't need a Client
Component wrapper to render it where as doing it with effects would
require more complex wrappers. By picking Blobs over base64,
client-navigations can use the more optimized binary encoding in the RSC
protocol.
- The timing aspect of coordinating it with Suspensey images and image
decoding is a bit tricky to get right because if you set it in an effect
it's too late because you've already rendered it.
- SSR gets complicated when done in user space because you have to
handle both branches. Likely with `useSyncExternalStore`.
- By having it built-in we could optimize the payloads shared between
RSC payloads embedded in the HTML and data URLs.

This does not support objects for `<source src>` nor `<img srcset>`.
Those don't really have equivalents in the DOM neither. They're mainly
for picking an option when you don't know programmatically. However, for
this use case you're really better off picking a variant before
generating the blobs.

We may support Response objects in the future too as per
https://github.com/whatwg/fetch/issues/49
2025-04-08 12:11:41 -04:00

114 lines
3.3 KiB
JavaScript

/**
* Copyright (c) Meta Platforms, Inc. and affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
* @flow
*/
/* global Bun */
type BunReadableStreamController = ReadableStreamController & {
end(): mixed,
write(data: Chunk | BinaryChunk): void,
error(error: Error): void,
flush?: () => void,
};
export type Destination = BunReadableStreamController;
export type PrecomputedChunk = string;
export opaque type Chunk = string;
export type BinaryChunk = $ArrayBufferView;
export function scheduleWork(callback: () => void) {
setTimeout(callback, 0);
}
export const scheduleMicrotask = queueMicrotask;
export function flushBuffered(destination: Destination) {
// Bun direct streams provide a flush function.
// If we don't have any more data to send right now.
// Flush whatever is in the buffer to the wire.
if (typeof destination.flush === 'function') {
destination.flush();
}
}
export function beginWriting(destination: Destination) {}
export function writeChunk(
destination: Destination,
chunk: PrecomputedChunk | Chunk | BinaryChunk,
): void {
if (chunk.length === 0) {
return;
}
destination.write(chunk);
}
export function writeChunkAndReturn(
destination: Destination,
chunk: PrecomputedChunk | Chunk | BinaryChunk,
): boolean {
return !!destination.write(chunk);
}
export function completeWriting(destination: Destination) {}
export function close(destination: Destination) {
destination.end();
}
export function stringToChunk(content: string): Chunk {
return content;
}
export function stringToPrecomputedChunk(content: string): PrecomputedChunk {
return content;
}
export function typedArrayToBinaryChunk(
content: $ArrayBufferView,
): BinaryChunk {
// TODO: Does this needs to be cloned if it's transferred in enqueue()?
return content;
}
export function byteLengthOfChunk(chunk: Chunk | PrecomputedChunk): number {
return Buffer.byteLength(chunk, 'utf8');
}
export function byteLengthOfBinaryChunk(chunk: BinaryChunk): number {
return chunk.byteLength;
}
export function closeWithError(destination: Destination, error: mixed): void {
if (typeof destination.error === 'function') {
// $FlowFixMe[incompatible-call]: This is an Error object or the destination accepts other types.
destination.error(error);
} else {
// Earlier implementations doesn't support this method. In that environment you're
// supposed to throw from a promise returned but we don't return a promise in our
// approach. We could fork this implementation but this is environment is an edge
// case to begin with. It's even less common to run this in an older environment.
// Even then, this is not where errors are supposed to happen and they get reported
// to a global callback in addition to this anyway. So it's fine just to close this.
destination.close();
}
}
export function createFastHash(input: string): string | number {
return Bun.hash(input);
}
export function readAsDataURL(blob: Blob): Promise<string> {
return blob.arrayBuffer().then(arrayBuffer => {
const encoded = Buffer.from(arrayBuffer).toString('base64');
const mimeType = blob.type || 'application/octet-stream';
return 'data:' + mimeType + ';base64,' + encoded;
});
}