Files
react/packages/react-markup/src/ReactMarkupServer.js
Sebastian Markbåge bbc13fa17b [Flight] Add Debug Channel option for stateful connection to the backend in DEV (#33627)
This adds plumbing for opening a stream from the Flight Client to the
Flight Server so it can ask for more data on-demand. In this mode, the
Flight Server keeps the connection open as long as the client is still
alive and there's more objects to load. It retains any depth limited
objects so that they can be asked for later. In this first PR it just
releases the object when it's discovered on the server and doesn't
actually lazy load it yet. That's coming in a follow up.

This strategy is built on the model that each request has its own
channel for this. Instead of some global registry. That ensures that
referential identity is preserved within a Request and the Request can
refer to previously written objects by reference.

The fixture implements a WebSocket per request but it doesn't have to be
done that way. It can be multiplexed through an existing WebSocket for
example. The current protocol is just a Readable(Stream) on the server
and WritableStream on the client. It could even be sent through a HTTP
request body if browsers implemented full duplex (which they don't).

This PR only implements the direction of messages from Client to Server.
However, I also plan on adding Debug Channel in the other direction to
allow debug info (optionally) be sent from Server to Client through this
channel instead of through the main RSC request. So the `debugChannel`
option will be able to take writable or readable or both.

---------

Co-authored-by: Hendrik Liebau <mail@hendrik-liebau.de>
2025-06-24 11:16:09 -04:00

236 lines
6.9 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
*/
import type {ReactNodeList} from 'shared/ReactTypes';
import type {LazyComponent} from 'react/src/ReactLazy';
import type {ErrorInfo} from 'react-server/src/ReactFizzServer';
import ReactVersion from 'shared/ReactVersion';
import ReactSharedInternalsServer from 'react-server/src/ReactSharedInternalsServer';
import ReactSharedInternalsClient from 'shared/ReactSharedInternals';
import {
createRequest as createFlightRequest,
startWork as startFlightWork,
startFlowing as startFlightFlowing,
abort as abortFlight,
} from 'react-server/src/ReactFlightServer';
import {
createResponse as createFlightResponse,
getRoot as getFlightRoot,
processStringChunk as processFlightStringChunk,
close as closeFlight,
} from 'react-client/src/ReactFlightClient';
import {
createRequest as createFizzRequest,
startWork as startFizzWork,
startFlowing as startFizzFlowing,
abort as abortFizz,
} from 'react-server/src/ReactFizzServer';
import {
createResumableState,
createRenderState,
createRootFormatContext,
} from './ReactFizzConfigMarkup';
type ReactMarkupNodeList =
// This is the intersection of ReactNodeList and ReactClientValue minus
// Client/ServerReferences.
| React$Element<React$ComponentType<any>>
| LazyComponent<ReactMarkupNodeList, any>
| React$Element<string>
| string
| boolean
| number
| symbol
| null
| void
| bigint
| $AsyncIterable<ReactMarkupNodeList, ReactMarkupNodeList, void>
| $AsyncIterator<ReactMarkupNodeList, ReactMarkupNodeList, void>
| Iterable<ReactMarkupNodeList>
| Iterator<ReactMarkupNodeList>
| Array<ReactMarkupNodeList>
| Promise<ReactMarkupNodeList>; // Thenable<ReactMarkupNodeList>
type MarkupOptions = {
identifierPrefix?: string,
signal?: AbortSignal,
onError?: (error: mixed, errorInfo: ErrorInfo) => ?string,
};
function noServerCallOrFormAction() {
throw new Error(
'renderToHTML should not have emitted Server References. This is a bug in React.',
);
}
export function experimental_renderToHTML(
children: ReactMarkupNodeList,
options?: MarkupOptions,
): Promise<string> {
return new Promise((resolve, reject) => {
const flightDestination = {
push(chunk: string | null): boolean {
if (chunk !== null) {
processFlightStringChunk(flightResponse, chunk);
} else {
closeFlight(flightResponse);
}
return true;
},
destroy(error: mixed): void {
abortFizz(fizzRequest, error);
reject(error);
},
};
let buffer = '';
const fizzDestination = {
// $FlowFixMe[missing-local-annot]
push(chunk) {
if (chunk !== null) {
buffer += chunk;
} else {
// null indicates that we finished
resolve(buffer);
}
return true;
},
// $FlowFixMe[missing-local-annot]
destroy(error) {
abortFlight(flightRequest, error);
reject(error);
},
};
let stashErrorIdx = 1;
const stashedErrors: Map<string, mixed> = new Map();
function handleFlightError(error: mixed): string {
// For Flight errors we don't immediately reject, because they might not matter
// to the output of the HTML. We stash the error with a digest in case we need
// to get to the original error from the Fizz render.
const id = '' + stashErrorIdx++;
stashedErrors.set(id, error);
return id;
}
function handleError(error: mixed, errorInfo: ErrorInfo) {
if (typeof error === 'object' && error !== null) {
const id = error.digest;
// Note that the original error might be `undefined` so we need a has check.
if (typeof id === 'string' && stashedErrors.has(id)) {
// Get the original error thrown inside Flight.
error = stashedErrors.get(id);
}
}
// Any error rejects the promise, regardless of where it happened.
// Unlike other React SSR we don't want to put Suspense boundaries into
// client rendering mode because there's no client rendering here.
reject(error);
const onError = options && options.onError;
if (onError) {
if (__DEV__) {
const prevGetCurrentStackImpl =
ReactSharedInternalsServer.getCurrentStack;
// We're inside a "client" callback from Fizz but we only have access to the
// "server" runtime so to get access to a stack trace within this callback we
// need to override it to get it from the client runtime.
ReactSharedInternalsServer.getCurrentStack =
ReactSharedInternalsClient.getCurrentStack;
try {
onError(error, errorInfo);
} finally {
ReactSharedInternalsServer.getCurrentStack =
prevGetCurrentStackImpl;
}
} else {
onError(error, errorInfo);
}
}
}
const flightRequest = createFlightRequest(
// $FlowFixMe: This should be a subtype but not everything is typed covariant.
children,
null,
handleFlightError,
options ? options.identifierPrefix : undefined,
undefined,
undefined,
'Markup',
undefined,
false,
);
const flightResponse = createFlightResponse(
null,
null,
null,
noServerCallOrFormAction,
noServerCallOrFormAction,
undefined,
undefined,
undefined,
false,
);
const resumableState = createResumableState(
options ? options.identifierPrefix : undefined,
undefined,
);
const root = getFlightRoot<ReactNodeList>(flightResponse);
const fizzRequest = createFizzRequest(
// $FlowFixMe: Thenables as children are supported.
root,
resumableState,
createRenderState(
resumableState,
undefined,
undefined,
undefined,
undefined,
undefined,
),
createRootFormatContext(),
Infinity,
handleError,
undefined,
undefined,
undefined,
undefined,
undefined,
undefined,
);
if (options && options.signal) {
const signal = options.signal;
if (signal.aborted) {
abortFlight(flightRequest, (signal: any).reason);
abortFizz(fizzRequest, (signal: any).reason);
} else {
const listener = () => {
abortFlight(flightRequest, (signal: any).reason);
abortFizz(fizzRequest, (signal: any).reason);
signal.removeEventListener('abort', listener);
};
signal.addEventListener('abort', listener);
}
}
startFlightWork(flightRequest);
startFlightFlowing(flightRequest, flightDestination);
startFizzWork(fizzRequest);
startFizzFlowing(fizzRequest, fizzDestination);
});
}
export {ReactVersion as version};