next/dist/esm/server/response-cache/index.js

The React Framework

import { Batcher } from '../../lib/batcher';
import { scheduleOnNextTick } from '../../lib/scheduler';
import { fromResponseCacheEntry, routeKindToIncrementalCacheKind, toResponseCacheEntry } from './utils';
export * from './types';
export default class ResponseCache {
    constructor(minimalMode){
        this.batcher = Batcher.create({
            // Ensure on-demand revalidate doesn't block normal requests, it should be
            // safe to run an on-demand revalidate for the same key as a normal request.
            cacheKeyFn: ({ key, isOnDemandRevalidate })=>`${key}-${isOnDemandRevalidate ? '1' : '0'}`,
            // We wait to do any async work until after we've added our promise to
            // `pendingResponses` to ensure that any any other calls will reuse the
            // same promise until we've fully finished our work.
            schedulerFn: scheduleOnNextTick
        });
        // this is a hack to avoid Webpack knowing this is equal to this.minimalMode
        // because we replace this.minimalMode to true in production bundles.
        const minimalModeKey = 'minimalMode';
        this[minimalModeKey] = minimalMode;
    }
    async get(key, responseGenerator, context) {
        // If there is no key for the cache, we can't possibly look this up in the
        // cache so just return the result of the response generator.
        if (!key) {
            return responseGenerator({
                hasResolved: false,
                previousCacheEntry: null
            });
        }
        const { incrementalCache, isOnDemandRevalidate = false, isFallback = false, isRoutePPREnabled = false } = context;
        const response = await this.batcher.batch({
            key,
            isOnDemandRevalidate
        }, async (cacheKey, resolve)=>{
            var _this_previousCacheItem;
            // We keep the previous cache entry around to leverage when the
            // incremental cache is disabled in minimal mode.
            if (this.minimalMode && ((_this_previousCacheItem = this.previousCacheItem) == null ? void 0 : _this_previousCacheItem.key) === cacheKey && this.previousCacheItem.expiresAt > Date.now()) {
                return this.previousCacheItem.entry;
            }
            // Coerce the kindHint into a given kind for the incremental cache.
            const kind = routeKindToIncrementalCacheKind(context.routeKind);
            let resolved = false;
            let cachedResponse = null;
            try {
                cachedResponse = !this.minimalMode ? await incrementalCache.get(key, {
                    kind,
                    isRoutePPREnabled: context.isRoutePPREnabled,
                    isFallback
                }) : null;
                if (cachedResponse && !isOnDemandRevalidate) {
                    resolve(cachedResponse);
                    resolved = true;
                    if (!cachedResponse.isStale || context.isPrefetch) {
                        // The cached value is still valid, so we don't need
                        // to update it yet.
                        return null;
                    }
                }
                const cacheEntry = await responseGenerator({
                    hasResolved: resolved,
                    previousCacheEntry: cachedResponse,
                    isRevalidating: true
                });
                // If the cache entry couldn't be generated, we don't want to cache
                // the result.
                if (!cacheEntry) {
                    // Unset the previous cache item if it was set.
                    if (this.minimalMode) this.previousCacheItem = undefined;
                    return null;
                }
                const resolveValue = await fromResponseCacheEntry({
                    ...cacheEntry,
                    isMiss: !cachedResponse
                });
                if (!resolveValue) {
                    // Unset the previous cache item if it was set.
                    if (this.minimalMode) this.previousCacheItem = undefined;
                    return null;
                }
                // For on-demand revalidate wait to resolve until cache is set.
                // Otherwise resolve now.
                if (!isOnDemandRevalidate && !resolved) {
                    resolve(resolveValue);
                    resolved = true;
                }
                // We want to persist the result only if it has a cache control value
                // defined.
                if (resolveValue.cacheControl) {
                    if (this.minimalMode) {
                        this.previousCacheItem = {
                            key: cacheKey,
                            entry: resolveValue,
                            expiresAt: Date.now() + 1000
                        };
                    } else {
                        await incrementalCache.set(key, resolveValue.value, {
                            cacheControl: resolveValue.cacheControl,
                            isRoutePPREnabled,
                            isFallback
                        });
                    }
                }
                return resolveValue;
            } catch (err) {
                // When a path is erroring we automatically re-set the existing cache
                // with new revalidate and expire times to prevent non-stop retrying.
                if (cachedResponse == null ? void 0 : cachedResponse.cacheControl) {
                    const newRevalidate = Math.min(Math.max(cachedResponse.cacheControl.revalidate || 3, 3), 30);
                    const newExpire = cachedResponse.cacheControl.expire === undefined ? undefined : Math.max(newRevalidate + 3, cachedResponse.cacheControl.expire);
                    await incrementalCache.set(key, cachedResponse.value, {
                        cacheControl: {
                            revalidate: newRevalidate,
                            expire: newExpire
                        },
                        isRoutePPREnabled,
                        isFallback
                    });
                }
                // While revalidating in the background we can't reject as we already
                // resolved the cache entry so log the error here.
                if (resolved) {
                    console.error(err);
                    return null;
                }
                // We haven't resolved yet, so let's throw to indicate an error.
                throw err;
            }
        });
        return toResponseCacheEntry(response);
    }
}

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