next
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The React Framework
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JavaScript
;
Object.defineProperty(exports, "__esModule", {
value: true
});
0 && (module.exports = {
EntryStatus: null,
readExactRouteCacheEntry: null,
readRouteCacheEntry: null,
readSegmentCacheEntry: null,
requestRouteCacheEntryFromCache: null,
requestSegmentEntryFromCache: null,
waitForSegmentCacheEntry: null
});
function _export(target, all) {
for(var name in all)Object.defineProperty(target, name, {
enumerable: true,
get: all[name]
});
}
_export(exports, {
EntryStatus: function() {
return EntryStatus;
},
readExactRouteCacheEntry: function() {
return readExactRouteCacheEntry;
},
readRouteCacheEntry: function() {
return readRouteCacheEntry;
},
readSegmentCacheEntry: function() {
return readSegmentCacheEntry;
},
requestRouteCacheEntryFromCache: function() {
return requestRouteCacheEntryFromCache;
},
requestSegmentEntryFromCache: function() {
return requestSegmentEntryFromCache;
},
waitForSegmentCacheEntry: function() {
return waitForSegmentCacheEntry;
}
});
const _approuterheaders = require("../app-router-headers");
const _fetchserverresponse = require("../router-reducer/fetch-server-response");
const _scheduler = require("./scheduler");
const _appbuildid = require("../../app-build-id");
const _createhreffromurl = require("../router-reducer/create-href-from-url");
const _tuplemap = require("./tuple-map");
const _lru = require("./lru");
var EntryStatus = /*#__PURE__*/ function(EntryStatus) {
EntryStatus[EntryStatus["Pending"] = 0] = "Pending";
EntryStatus[EntryStatus["Rejected"] = 1] = "Rejected";
EntryStatus[EntryStatus["Fulfilled"] = 2] = "Fulfilled";
return EntryStatus;
}({});
const routeCacheMap = (0, _tuplemap.createTupleMap)();
// We use an LRU for memory management. We must update this whenever we add or
// remove a new cache entry, or when an entry changes size.
// TODO: I chose the max size somewhat arbitrarily. Consider setting this based
// on navigator.deviceMemory, or some other heuristic. We should make this
// customizable via the Next.js config, too.
const maxRouteLruSize = 10 * 1024 * 1024 // 10 MB
;
const routeCacheLru = (0, _lru.createLRU)(maxRouteLruSize, onRouteLRUEviction);
// TODO: We may eventually store segment entries in a tuple map, too, to
// account for search params.
const segmentCacheMap = new Map();
// NOTE: Segments and Route entries are managed by separate LRUs. We could
// combine them into a single LRU, but because they are separate types, we'd
// need to wrap each one in an extra LRU node (to maintain monomorphism, at the
// cost of additional memory).
const maxSegmentLruSize = 50 * 1024 * 1024 // 50 MB
;
const segmentCacheLru = (0, _lru.createLRU)(maxSegmentLruSize, onSegmentLRUEviction);
function readExactRouteCacheEntry(now, href, nextUrl) {
const keypath = nextUrl === null ? [
href
] : [
href,
nextUrl
];
const existingEntry = routeCacheMap.get(keypath);
if (existingEntry !== null) {
// Check if the entry is stale
if (existingEntry.staleAt > now) {
// Reuse the existing entry.
// Since this is an access, move the entry to the front of the LRU.
routeCacheLru.put(existingEntry);
return existingEntry;
} else {
// Evict the stale entry from the cache.
deleteRouteFromCache(existingEntry, keypath);
}
}
return null;
}
function readRouteCacheEntry(now, key) {
// First check if there's a non-intercepted entry. Most routes cannot be
// intercepted, so this is the common case.
const nonInterceptedEntry = readExactRouteCacheEntry(now, key.href, null);
if (nonInterceptedEntry !== null && !nonInterceptedEntry.couldBeIntercepted) {
// Found a match, and the route cannot be intercepted. We can reuse it.
return nonInterceptedEntry;
}
// There was no match. Check again but include the Next-Url this time.
return readExactRouteCacheEntry(now, key.href, key.nextUrl);
}
function readSegmentCacheEntry(now, path) {
const existingEntry = segmentCacheMap.get(path);
if (existingEntry !== undefined) {
// Check if the entry is stale
if (existingEntry.staleAt > now) {
// Reuse the existing entry.
// Since this is an access, move the entry to the front of the LRU.
segmentCacheLru.put(existingEntry);
return existingEntry;
} else {
// Evict the stale entry from the cache.
deleteSegmentFromCache(existingEntry, path);
}
}
return null;
}
function waitForSegmentCacheEntry(pendingEntry) {
// Because the entry is pending, there's already a in-progress request.
// Attach a promise to the entry that will resolve when the server responds.
let promiseWithResolvers = pendingEntry.promise;
if (promiseWithResolvers === null) {
promiseWithResolvers = pendingEntry.promise = createPromiseWithResolvers();
} else {
// There's already a promise we can use
}
return promiseWithResolvers.promise;
}
function requestRouteCacheEntryFromCache(now, task) {
const key = task.key;
// First check if there's a non-intercepted entry. Most routes cannot be
// intercepted, so this is the common case.
const nonInterceptedEntry = readExactRouteCacheEntry(now, key.href, null);
if (nonInterceptedEntry !== null && !nonInterceptedEntry.couldBeIntercepted) {
// Found a match, and the route cannot be intercepted. We can reuse it.
return nonInterceptedEntry;
}
// There was no match. Check again but include the Next-Url this time.
const exactEntry = readExactRouteCacheEntry(now, key.href, key.nextUrl);
if (exactEntry !== null) {
return exactEntry;
}
// Create a pending entry and spawn a request for its data.
const pendingEntry = {
canonicalUrl: null,
status: 0,
blockedTasks: null,
tree: null,
head: null,
isHeadPartial: true,
// If the request takes longer than a minute, a subsequent request should
// retry instead of waiting for this one.
//
// When the response is received, this value will be replaced by a new value
// based on the stale time sent from the server.
staleAt: now + 60 * 1000,
// This is initialized to true because we don't know yet whether the route
// could be intercepted. It's only set to false once we receive a response
// from the server.
couldBeIntercepted: true,
// LRU-related fields
keypath: null,
next: null,
prev: null,
size: 0
};
(0, _scheduler.spawnPrefetchSubtask)(fetchRouteOnCacheMiss(pendingEntry, task));
const keypath = key.nextUrl === null ? [
key.href
] : [
key.href,
key.nextUrl
];
routeCacheMap.set(keypath, pendingEntry);
// Stash the keypath on the entry so we know how to remove it from the map
// if it gets evicted from the LRU.
pendingEntry.keypath = keypath;
routeCacheLru.put(pendingEntry);
return pendingEntry;
}
function requestSegmentEntryFromCache(now, task, route, path, accessToken) {
const existingEntry = readSegmentCacheEntry(now, path);
if (existingEntry !== null) {
return existingEntry;
}
// Create a pending entry and spawn a request for its data.
const pendingEntry = {
status: 0,
rsc: null,
loading: null,
staleAt: route.staleAt,
isPartial: true,
promise: null,
// LRU-related fields
key: null,
next: null,
prev: null,
size: 0
};
(0, _scheduler.spawnPrefetchSubtask)(fetchSegmentEntryOnCacheMiss(route, pendingEntry, task.key, path, accessToken));
segmentCacheMap.set(path, pendingEntry);
// Stash the keypath on the entry so we know how to remove it from the map
// if it gets evicted from the LRU.
pendingEntry.key = path;
segmentCacheLru.put(pendingEntry);
return pendingEntry;
}
function deleteRouteFromCache(entry, keypath) {
pingBlockedTasks(entry);
routeCacheMap.delete(keypath);
routeCacheLru.delete(entry);
}
function deleteSegmentFromCache(entry, key) {
cancelEntryListeners(entry);
segmentCacheMap.delete(key);
segmentCacheLru.delete(entry);
}
function onRouteLRUEviction(entry) {
// The LRU evicted this entry. Remove it from the map.
const keypath = entry.keypath;
if (keypath !== null) {
entry.keypath = null;
pingBlockedTasks(entry);
routeCacheMap.delete(keypath);
}
}
function onSegmentLRUEviction(entry) {
// The LRU evicted this entry. Remove it from the map.
const key = entry.key;
if (key !== null) {
entry.key = null;
cancelEntryListeners(entry);
segmentCacheMap.delete(key);
}
}
function cancelEntryListeners(entry) {
if (entry.status === 0 && entry.promise !== null) {
// There were listeners for this entry. Resolve them with `null` to indicate
// that the prefetch failed. It's up to the listener to decide how to handle
// this case.
// NOTE: We don't currently propagate the reason the prefetch was canceled
// but we could by accepting a `reason` argument.
entry.promise.resolve(null);
entry.promise = null;
}
}
function pingBlockedTasks(entry) {
const blockedTasks = entry.blockedTasks;
if (blockedTasks !== null) {
for (const task of blockedTasks){
(0, _scheduler.pingPrefetchTask)(task);
}
entry.blockedTasks = null;
}
}
function fulfillRouteCacheEntry(entry, tree, head, isHeadPartial, staleAt, couldBeIntercepted, canonicalUrl) {
const fulfilledEntry = entry;
fulfilledEntry.status = 2;
fulfilledEntry.tree = tree;
fulfilledEntry.head = head;
fulfilledEntry.isHeadPartial = isHeadPartial;
fulfilledEntry.staleAt = staleAt;
fulfilledEntry.couldBeIntercepted = couldBeIntercepted;
fulfilledEntry.canonicalUrl = canonicalUrl;
pingBlockedTasks(entry);
return fulfilledEntry;
}
function fulfillSegmentCacheEntry(segmentCacheEntry, rsc, loading, staleAt, isPartial) {
const fulfilledEntry = segmentCacheEntry;
fulfilledEntry.status = 2;
fulfilledEntry.rsc = rsc;
fulfilledEntry.loading = loading;
fulfilledEntry.staleAt = staleAt;
fulfilledEntry.isPartial = isPartial;
// Resolve any listeners that were waiting for this data.
if (segmentCacheEntry.promise !== null) {
segmentCacheEntry.promise.resolve(fulfilledEntry);
// Free the promise for garbage collection.
fulfilledEntry.promise = null;
}
}
function rejectRouteCacheEntry(entry, staleAt) {
const rejectedEntry = entry;
rejectedEntry.status = 1;
rejectedEntry.staleAt = staleAt;
pingBlockedTasks(entry);
}
function rejectSegmentCacheEntry(entry, staleAt) {
const rejectedEntry = entry;
rejectedEntry.status = 1;
rejectedEntry.staleAt = staleAt;
if (entry.promise !== null) {
// NOTE: We don't currently propagate the reason the prefetch was canceled
// but we could by accepting a `reason` argument.
entry.promise.resolve(null);
entry.promise = null;
}
}
async function fetchRouteOnCacheMiss(entry, task) {
// This function is allowed to use async/await because it contains the actual
// fetch that gets issued on a cache miss. Notice though that it does not
// return anything; it writes the result to the cache entry directly, then
// pings the scheduler to unblock the corresponding prefetch task.
const key = task.key;
const href = key.href;
const nextUrl = key.nextUrl;
try {
const response = await fetchSegmentPrefetchResponse(href, '/_tree', nextUrl);
if (!response || !response.ok || // 204 is a Cache miss. Though theoretically this shouldn't happen when
// PPR is enabled, because we always respond to route tree requests, even
// if it needs to be blockingly generated on demand.
response.status === 204 || !response.body) {
// Server responded with an error, or with a miss. We should still cache
// the response, but we can try again after 10 seconds.
rejectRouteCacheEntry(entry, Date.now() + 10 * 1000);
return;
}
const prefetchStream = createPrefetchResponseStream(response.body, routeCacheLru, entry);
const serverData = await (0, _fetchserverresponse.createFromNextReadableStream)(prefetchStream);
if (serverData.buildId !== (0, _appbuildid.getAppBuildId)()) {
// The server build does not match the client. Treat as a 404. During
// an actual navigation, the router will trigger an MPA navigation.
// TODO: Consider moving the build ID to a response header so we can check
// it before decoding the response, and so there's one way of checking
// across all response types.
rejectRouteCacheEntry(entry, Date.now() + 10 * 1000);
return;
}
// This is a bit convoluted but it's taken from router-reducer and
// fetch-server-response
const canonicalUrl = response.redirected ? (0, _createhreffromurl.createHrefFromUrl)((0, _fetchserverresponse.urlToUrlWithoutFlightMarker)(response.url)) : href;
// Check whether the response varies based on the Next-Url header.
const varyHeader = response.headers.get('vary');
const couldBeIntercepted = varyHeader !== null && varyHeader.includes(_approuterheaders.NEXT_URL);
fulfillRouteCacheEntry(entry, serverData.tree, serverData.head, serverData.isHeadPartial, Date.now() + serverData.staleTime, couldBeIntercepted, canonicalUrl);
if (!couldBeIntercepted && nextUrl !== null) {
// This route will never be intercepted. So we can use this entry for all
// requests to this route, regardless of the Next-Url header. This works
// because when reading the cache we always check for a valid
// non-intercepted entry first.
//
// Re-key the entry. Since we're in an async task, we must first confirm
// that the entry hasn't been concurrently modified by a different task.
const currentKeypath = [
href,
nextUrl
];
const expectedEntry = routeCacheMap.get(currentKeypath);
if (expectedEntry === entry) {
routeCacheMap.delete(currentKeypath);
const newKeypath = [
href
];
routeCacheMap.set(newKeypath, entry);
// We don't need to update the LRU because the entry is already in it.
// But since we changed the keypath, we do need to update that, so we
// know how to remove it from the map if it gets evicted from the LRU.
entry.keypath = newKeypath;
} else {
// Something else modified this entry already. Since the re-keying is
// just a performance optimization, we can safely skip it.
}
}
} catch (error) {
// Either the connection itself failed, or something bad happened while
// decoding the response.
rejectRouteCacheEntry(entry, Date.now() + 10 * 1000);
}
}
async function fetchSegmentEntryOnCacheMiss(route, segmentCacheEntry, routeKey, segmentPath, accessToken) {
// This function is allowed to use async/await because it contains the actual
// fetch that gets issued on a cache miss. Notice though that it does not
// return anything; it writes the result to the cache entry directly.
//
// Segment fetches are non-blocking so we don't need to ping the scheduler
// on completion.
const href = routeKey.href;
try {
const response = await fetchSegmentPrefetchResponse(href, accessToken === '' ? segmentPath : segmentPath + "." + accessToken, routeKey.nextUrl);
if (!response || !response.ok || response.status === 204 || // Cache miss
!response.body) {
// Server responded with an error, or with a miss. We should still cache
// the response, but we can try again after 10 seconds.
rejectSegmentCacheEntry(segmentCacheEntry, Date.now() + 10 * 1000);
return;
}
// Wrap the original stream in a new stream that never closes. That way the
// Flight client doesn't error if there's a hanging promise.
const prefetchStream = createPrefetchResponseStream(response.body, segmentCacheLru, segmentCacheEntry);
const serverData = await (0, _fetchserverresponse.createFromNextReadableStream)(prefetchStream);
if (serverData.buildId !== (0, _appbuildid.getAppBuildId)()) {
// The server build does not match the client. Treat as a 404. During
// an actual navigation, the router will trigger an MPA navigation.
// TODO: Consider moving the build ID to a response header so we can check
// it before decoding the response, and so there's one way of checking
// across all response types.
rejectSegmentCacheEntry(segmentCacheEntry, Date.now() + 10 * 1000);
return;
}
fulfillSegmentCacheEntry(segmentCacheEntry, serverData.rsc, serverData.loading, // TODO: The server does not currently provide per-segment stale time.
// So we use the stale time of the route.
route.staleAt, serverData.isPartial);
} catch (error) {
// Either the connection itself failed, or something bad happened while
// decoding the response.
rejectSegmentCacheEntry(segmentCacheEntry, Date.now() + 10 * 1000);
}
}
async function fetchSegmentPrefetchResponse(href, segmentPath, nextUrl) {
const headers = {
[_approuterheaders.RSC_HEADER]: '1',
[_approuterheaders.NEXT_ROUTER_PREFETCH_HEADER]: '1',
[_approuterheaders.NEXT_ROUTER_SEGMENT_PREFETCH_HEADER]: segmentPath
};
if (nextUrl !== null) {
headers[_approuterheaders.NEXT_URL] = nextUrl;
}
const fetchPriority = 'low';
const responsePromise = (0, _fetchserverresponse.createFetch)(new URL(href), headers, fetchPriority);
(0, _scheduler.trackPrefetchRequestBandwidth)(responsePromise);
const response = await responsePromise;
const contentType = response.headers.get('content-type');
const isFlightResponse = contentType && contentType.startsWith(_approuterheaders.RSC_CONTENT_TYPE_HEADER);
if (!response.ok || !isFlightResponse) {
return null;
}
return response;
}
function createPrefetchResponseStream(originalFlightStream, lru, lruEntry) {
// 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.
//
// While processing the original stream, we also incrementally update the size
// of the cache entry in the LRU.
let totalByteLength = 0;
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);
// Incrementally update the size of the cache entry in the LRU.
// NOTE: Since prefetch responses are delivered in a single chunk,
// it's not really necessary to do this streamingly, but I'm doing it
// anyway in case this changes in the future.
totalByteLength += value.byteLength;
lru.updateSize(lruEntry, totalByteLength);
continue;
}
// The server stream has closed. Exit, but intentionally do not close
// the target stream.
return;
}
}
});
}
function createPromiseWithResolvers() {
// Shim of Stage 4 Promise.withResolvers proposal
let resolve;
let reject;
const promise = new Promise((res, rej)=>{
resolve = res;
reject = rej;
});
return {
resolve: resolve,
reject: reject,
promise
};
}
if ((typeof exports.default === 'function' || (typeof exports.default === 'object' && exports.default !== null)) && typeof exports.default.__esModule === 'undefined') {
Object.defineProperty(exports.default, '__esModule', { value: true });
Object.assign(exports.default, exports);
module.exports = exports.default;
}
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