next/dist/server/app-render/collect-segment-data.js

The React Framework

/* eslint-disable @next/internal/no-ambiguous-jsx -- Bundled in entry-base so it gets the right JSX runtime. */ "use strict";
Object.defineProperty(exports, "__esModule", {
    value: true
});
Object.defineProperty(exports, "collectSegmentData", {
    enumerable: true,
    get: function() {
        return collectSegmentData;
    }
});
const _jsxruntime = require("react/jsx-runtime");
const _client = require("react-server-dom-webpack/client");
const _static = require("react-server-dom-webpack/static");
const _nodewebstreamshelper = require("../stream-utils/node-web-streams-helper");
const _scheduler = require("../../lib/scheduler");
const _segmentvalueencoding = require("../../shared/lib/segment-cache/segment-value-encoding");
const _createerrorhandler = require("./create-error-handler");
const filterStackFrame = process.env.NODE_ENV !== 'production' ? require('../lib/source-maps').filterStackFrameDEV : undefined;
const findSourceMapURL = process.env.NODE_ENV !== 'production' ? require('../lib/source-maps').findSourceMapURLDEV : undefined;
function onSegmentPrerenderError(error) {
    const digest = (0, _createerrorhandler.getDigestForWellKnownError)(error);
    if (digest) {
        return digest;
    }
// We don't need to log the errors because we would have already done that
// when generating the original Flight stream for the whole page.
}
async function collectSegmentData(isCacheComponentsEnabled, fullPageDataBuffer, staleTime, clientModules, serverConsumerManifest) {
    // Traverse the router tree and generate a prefetch response for each segment.
    // A mutable map to collect the results as we traverse the route tree.
    const resultMap = new Map();
    // Before we start, warm up the module cache by decoding the page data once.
    // Then we can assume that any remaining async tasks that occur the next time
    // are due to hanging promises caused by dynamic data access. Note we only
    // have to do this once per page, not per individual segment.
    //
    try {
        await (0, _client.createFromReadableStream)((0, _nodewebstreamshelper.streamFromBuffer)(fullPageDataBuffer), {
            findSourceMapURL,
            serverConsumerManifest
        });
        await (0, _scheduler.waitAtLeastOneReactRenderTask)();
    } catch  {}
    // Create an abort controller that we'll use to stop the stream.
    const abortController = new AbortController();
    const onCompletedProcessingRouteTree = async ()=>{
        // Since all we're doing is decoding and re-encoding a cached prerender, if
        // serializing the stream takes longer than a microtask, it must because of
        // hanging promises caused by dynamic data.
        await (0, _scheduler.waitAtLeastOneReactRenderTask)();
        abortController.abort();
    };
    // Generate a stream for the route tree prefetch. While we're walking the
    // tree, we'll also spawn additional tasks to generate the segment prefetches.
    // The promises for these tasks are pushed to a mutable array that we will
    // await once the route tree is fully rendered.
    const segmentTasks = [];
    const { prelude: treeStream } = await (0, _static.prerender)(// RootTreePrefetch is not a valid return type for a React component, but
    // we need to use a component so that when we decode the original stream
    // inside of it, the side effects are transferred to the new stream.
    // @ts-expect-error
    /*#__PURE__*/ (0, _jsxruntime.jsx)(PrefetchTreeData, {
        isClientParamParsingEnabled: isCacheComponentsEnabled,
        fullPageDataBuffer: fullPageDataBuffer,
        serverConsumerManifest: serverConsumerManifest,
        clientModules: clientModules,
        staleTime: staleTime,
        segmentTasks: segmentTasks,
        onCompletedProcessingRouteTree: onCompletedProcessingRouteTree
    }), clientModules, {
        filterStackFrame,
        signal: abortController.signal,
        onError: onSegmentPrerenderError
    });
    // Write the route tree to a special `/_tree` segment.
    const treeBuffer = await (0, _nodewebstreamshelper.streamToBuffer)(treeStream);
    resultMap.set('/_tree', treeBuffer);
    // Also output the entire full page data response
    resultMap.set('/_full', fullPageDataBuffer);
    // Now that we've finished rendering the route tree, all the segment tasks
    // should have been spawned. Await them in parallel and write the segment
    // prefetches to the result map.
    for (const [segmentPath, buffer] of (await Promise.all(segmentTasks))){
        resultMap.set(segmentPath, buffer);
    }
    return resultMap;
}
async function PrefetchTreeData({ isClientParamParsingEnabled, fullPageDataBuffer, serverConsumerManifest, clientModules, staleTime, segmentTasks, onCompletedProcessingRouteTree }) {
    // We're currently rendering a Flight response for the route tree prefetch.
    // Inside this component, decode the Flight stream for the whole page. This is
    // a hack to transfer the side effects from the original Flight stream (e.g.
    // Float preloads) onto the Flight stream for the tree prefetch.
    // TODO: React needs a better way to do this. Needed for Server Actions, too.
    const initialRSCPayload = await (0, _client.createFromReadableStream)(createUnclosingPrefetchStream((0, _nodewebstreamshelper.streamFromBuffer)(fullPageDataBuffer)), {
        findSourceMapURL,
        serverConsumerManifest
    });
    const buildId = initialRSCPayload.b;
    // FlightDataPath is an unsound type, hence the additional checks.
    const flightDataPaths = initialRSCPayload.f;
    if (flightDataPaths.length !== 1 && flightDataPaths[0].length !== 3) {
        console.error('Internal Next.js error: InitialRSCPayload does not match the expected ' + 'shape for a prerendered page during segment prefetch generation.');
        return null;
    }
    const flightRouterState = flightDataPaths[0][0];
    const seedData = flightDataPaths[0][1];
    const head = flightDataPaths[0][2];
    // Compute the route metadata tree by traversing the FlightRouterState. As we
    // walk the tree, we will also spawn a task to produce a prefetch response for
    // each segment.
    const tree = collectSegmentDataImpl(isClientParamParsingEnabled, flightRouterState, buildId, seedData, clientModules, _segmentvalueencoding.ROOT_SEGMENT_REQUEST_KEY, segmentTasks);
    // Also spawn a task to produce a prefetch response for the "head" segment.
    // The head contains metadata, like the title; it's not really a route
    // segment, but it contains RSC data, so it's treated like a segment by
    // the client cache.
    segmentTasks.push((0, _scheduler.waitAtLeastOneReactRenderTask)().then(()=>renderSegmentPrefetch(buildId, head, null, _segmentvalueencoding.HEAD_REQUEST_KEY, clientModules)));
    // Notify the abort controller that we're done processing the route tree.
    // Anything async that happens after this point must be due to hanging
    // promises in the original stream.
    onCompletedProcessingRouteTree();
    // Render the route tree to a special `/_tree` segment.
    const treePrefetch = {
        buildId,
        tree,
        staleTime
    };
    return treePrefetch;
}
function collectSegmentDataImpl(isClientParamParsingEnabled, route, buildId, seedData, clientModules, requestKey, segmentTasks) {
    // Metadata about the segment. Sent as part of the tree prefetch. Null if
    // there are no children.
    let slotMetadata = null;
    const children = route[1];
    const seedDataChildren = seedData !== null ? seedData[1] : null;
    for(const parallelRouteKey in children){
        const childRoute = children[parallelRouteKey];
        const childSegment = childRoute[0];
        const childSeedData = seedDataChildren !== null ? seedDataChildren[parallelRouteKey] : null;
        const childRequestKey = (0, _segmentvalueencoding.appendSegmentRequestKeyPart)(requestKey, parallelRouteKey, (0, _segmentvalueencoding.createSegmentRequestKeyPart)(childSegment));
        const childTree = collectSegmentDataImpl(isClientParamParsingEnabled, childRoute, buildId, childSeedData, clientModules, childRequestKey, segmentTasks);
        if (slotMetadata === null) {
            slotMetadata = {};
        }
        slotMetadata[parallelRouteKey] = childTree;
    }
    const hasRuntimePrefetch = seedData !== null ? seedData[4] : false;
    if (seedData !== null) {
        // Spawn a task to write the segment data to a new Flight stream.
        segmentTasks.push(// Since we're already in the middle of a render, wait until after the
        // current task to escape the current rendering context.
        (0, _scheduler.waitAtLeastOneReactRenderTask)().then(()=>renderSegmentPrefetch(buildId, seedData[0], seedData[2], requestKey, clientModules)));
    } else {
    // This segment does not have any seed data. Skip generating a prefetch
    // response for it. We'll still include it in the route tree, though.
    // TODO: We should encode in the route tree whether a segment is missing
    // so we don't attempt to fetch it for no reason. As of now this shouldn't
    // ever happen in practice, though.
    }
    const segment = route[0];
    let name;
    let paramType = null;
    let paramKey = null;
    if (typeof segment === 'string') {
        name = segment;
        paramKey = segment;
        paramType = null;
    } else {
        name = segment[0];
        paramKey = segment[1];
        paramType = segment[2];
    }
    // Metadata about the segment. Sent to the client as part of the
    // tree prefetch.
    return {
        name,
        paramType,
        // This value is ommitted from the prefetch response when cacheComponents
        // is enabled.
        paramKey: isClientParamParsingEnabled ? null : paramKey,
        hasRuntimePrefetch,
        slots: slotMetadata,
        isRootLayout: route[4] === true
    };
}
async function renderSegmentPrefetch(buildId, rsc, loading, requestKey, clientModules) {
    // Render the segment data to a stream.
    // In the future, this is where we can include additional metadata, like the
    // stale time and cache tags.
    const segmentPrefetch = {
        buildId,
        rsc,
        loading,
        isPartial: await isPartialRSCData(rsc, clientModules)
    };
    // Since all we're doing is decoding and re-encoding a cached prerender, if
    // it takes longer than a microtask, it must because of hanging promises
    // caused by dynamic data. Abort the stream at the end of the current task.
    const abortController = new AbortController();
    (0, _scheduler.waitAtLeastOneReactRenderTask)().then(()=>abortController.abort());
    const { prelude: segmentStream } = await (0, _static.prerender)(segmentPrefetch, clientModules, {
        filterStackFrame,
        signal: abortController.signal,
        onError: onSegmentPrerenderError
    });
    const segmentBuffer = await (0, _nodewebstreamshelper.streamToBuffer)(segmentStream);
    if (requestKey === _segmentvalueencoding.ROOT_SEGMENT_REQUEST_KEY) {
        return [
            '/_index',
            segmentBuffer
        ];
    } else {
        return [
            requestKey,
            segmentBuffer
        ];
    }
}
async function isPartialRSCData(rsc, clientModules) {
    // We can determine if a segment contains only partial data if it takes longer
    // than a task to encode, because dynamic data is encoded as an infinite
    // promise. We must do this in a separate Flight prerender from the one that
    // actually generates the prefetch stream because we need to include
    // `isPartial` in the stream itself.
    let isPartial = false;
    const abortController = new AbortController();
    (0, _scheduler.waitAtLeastOneReactRenderTask)().then(()=>{
        // If we haven't yet finished the outer task, then it must be because we
        // accessed dynamic data.
        isPartial = true;
        abortController.abort();
    });
    await (0, _static.prerender)(rsc, clientModules, {
        filterStackFrame,
        signal: abortController.signal,
        onError () {}
    });
    return isPartial;
}
function createUnclosingPrefetchStream(originalFlightStream) {
    // When PPR is enabled, prefetch streams may contain references that never
    // resolve, because that's how we encode dynamic data access. In the decoded
    // object returned by the Flight client, these are reified into hanging
    // promises that suspend during render, which is effectively what we want.
    // The UI resolves when it switches to the dynamic data stream
    // (via useDeferredValue(dynamic, static)).
    //
    // However, the Flight implementation currently errors if the server closes
    // the response before all the references are resolved. As a cheat to work
    // around this, we wrap the original stream in a new stream that never closes,
    // and therefore doesn't error.
    const reader = originalFlightStream.getReader();
    return new ReadableStream({
        async pull (controller) {
            while(true){
                const { done, value } = await reader.read();
                if (!done) {
                    // Pass to the target stream and keep consuming the Flight response
                    // from the server.
                    controller.enqueue(value);
                    continue;
                }
                // The server stream has closed. Exit, but intentionally do not close
                // the target stream.
                return;
            }
        }
    });
}

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