revalidation-strategy-planner（再验证策略规划师）

Revalidation Strategy Planner

Analyze Next.js application routes and recommend optimal caching and revalidation strategies for performance and data freshness.

Overview

To optimize Next.js caching strategies:

1. Analyze route characteristics (data freshness requirements, update frequency)
2. Determine appropriate rendering strategy (SSG, ISR, SSR, streaming)
3. Configure revalidation intervals for ISR routes
4. Implement cache tags for on-demand revalidation
5. Set up streaming for progressive page loading

Rendering Strategies

Static Site Generation (SSG)

To use SSG for rarely changing content:

// app/about/page.tsx
export default async function AboutPage() {
  // Generated at build time, no revalidation
  return <div>About Us</div>;
}

Best for:

• Marketing pages
• Documentation
• Static content that rarely changes

Incremental Static Regeneration (ISR)

To use ISR for periodically updated content:

// app/entities/[id]/page.tsx
export const revalidate = 3600; // Revalidate every hour

export default async function EntityPage({ params }: { params: { id: string } }) {
  const entity = await fetchEntity(params.id);
  return <EntityDetail entity={entity} />;
}

Best for:

• Entity detail pages
• Blog posts
• Product listings
• Content with predictable update patterns

Server-Side Rendering (SSR)

To use SSR for real-time data:

// app/dashboard/page.tsx
export const dynamic = 'force-dynamic';

export default async function Dashboard() {
  const data = await fetchUserData();
  return <DashboardView data={data} />;
}

Best for:

• User dashboards
• Personalized content
• Real-time data displays
• Authentication-dependent pages

Streaming

To use streaming for progressive loading:

// app/timeline/page.tsx
import { Suspense } from 'react';

export default function TimelinePage() {
  return (
    <div>
      <TimelineHeader />
      <Suspense fallback={<TimelineLoader />}>
        <TimelineEvents />
      </Suspense>
    </div>
  );
}

Best for:

• Pages with slow data fetching
• Complex pages with multiple data sources
• Improving perceived performance

Consult references/rendering-strategies.md for detailed strategy comparison.

Revalidation Configuration

Time-Based Revalidation

To set revalidation intervals:

// Revalidate every 60 seconds
export const revalidate = 60;

// Revalidate every hour
export const revalidate = 3600;

// Revalidate every day
export const revalidate = 86400;

On-Demand Revalidation

To implement on-demand cache invalidation:

// app/api/revalidate/route.ts
import { revalidatePath, revalidateTag } from 'next/cache';
import { NextRequest } from 'next/server';

export async function POST(request: NextRequest) {
  const { path, tag } = await request.json();

  if (path) {
    revalidatePath(path);
  }

  if (tag) {
    revalidateTag(tag);
  }

  return Response.json({ revalidated: true, now: Date.now() });
}

Use from Server Actions:

'use server';

import { revalidatePath } from 'next/cache';

export async function updateEntity(id: string, data: EntityData) {
  await saveEntity(id, data);
  revalidatePath(`/entities/${id}`);
  revalidatePath('/entities');
}

Cache Tags

To implement cache tag-based revalidation:

// app/entities/[id]/page.tsx
export default async function EntityPage({ params }: { params: { id: string } }) {
  const entity = await fetch(`/api/entities/${params.id}`, {
    next: {
      tags: [`entity-${params.id}`, 'entities'],
    },
  });

  return <EntityDetail entity={entity} />;
}

Revalidate by tag:

import { revalidateTag } from 'next/cache';

// Revalidate all pages with 'entities' tag
revalidateTag('entities');

// Revalidate specific entity
revalidateTag(`entity-${entityId}`);

Reference assets/cache-tag-patterns.ts for cache tagging patterns.

Route Analysis

Use scripts/analyze_routes.py to analyze application routes and recommend strategies:

python scripts/analyze_routes.py ./app

Output includes:

• Route path
• Recommended rendering strategy
• Suggested revalidation interval
• Appropriate cache tags
• Reasoning for recommendations

Analysis Criteria

Consider these factors:

1. Data Freshness Requirements

- Real-time: SSR or very short revalidation (1-60s) - Near real-time: ISR with short interval (60-300s) - Periodic updates: ISR with medium interval (300-3600s) - Rarely changes: SSG or long interval (3600s+)

1. Update Frequency

- Continuous: SSR - Multiple times per hour: ISR (60-300s) - Hourly: ISR (3600s) - Daily: ISR (86400s) - Weekly+: SSG

1. Personalization

- User-specific: SSR - Role-based: SSR or ISR with user context - Public: SSG or ISR

1. Data Source Performance

- Fast (<100ms): Any strategy - Medium (100-500ms): Consider streaming - Slow (>500ms): Use streaming or aggressive caching

Consult references/decision-matrix.md for the complete decision matrix.

Implementation Patterns

Entity Detail Pages

To optimize entity pages:

// app/entities/[id]/page.tsx
export const revalidate = 1800; // 30 minutes

export async function generateStaticParams() {
  const entities = await fetchAllEntityIds();
  return entities.map((id) => ({ id: id.toString() }));
}

export default async function EntityPage({ params }: { params: { id: string } }) {
  const entity = await fetchEntity(params.id, {
    next: { tags: [`entity-${params.id}`, 'entities'] },
  });

  return <EntityDetail entity={entity} />;
}

List Pages

To optimize listing pages:

// app/entities/page.tsx
export const revalidate = 300; // 5 minutes

export default async function EntitiesPage({
  searchParams,
}: {
  searchParams: { page?: string };
}) {
  const page = parseInt(searchParams.page || '1');
  const entities = await fetchEntities(page, {
    next: { tags: ['entities'] },
  });

  return <EntityList entities={entities} />;
}

Timeline Pages

To optimize timeline with streaming:

// app/timeline/page.tsx
import { Suspense } from 'react';

export default function TimelinePage() {
  return (
    <div>
      <Suspense fallback={<TimelineHeaderSkeleton />}>
        <TimelineHeader />
      </Suspense>
      <Suspense fallback={<EventsSkeleton />}>
        <TimelineEvents />
      </Suspense>
    </div>
  );
}

async function TimelineEvents() {
  const events = await fetchTimelineEvents({
    next: { tags: ['timeline'], revalidate: 600 },
  });
  return <EventsList events={events} />;
}

Dashboard Pages

To implement personalized dashboard:

// app/dashboard/page.tsx
export const dynamic = 'force-dynamic';

export default async function DashboardPage() {
  const session = await getSession();
  const data = await fetchUserDashboard(session.userId);

  return (
    <div>
      <Suspense fallback={<StatsSkeleton />}>
        <DashboardStats userId={session.userId} />
      </Suspense>
      <Suspense fallback={<ActivitySkeleton />}>
        <RecentActivity userId={session.userId} />
      </Suspense>
    </div>
  );
}

Cache Invalidation Strategies

Granular Invalidation

To invalidate specific resources:

// After entity update
revalidateTag(`entity-${entityId}`);

// After relationship change
revalidateTag(`entity-${sourceId}`);
revalidateTag(`entity-${targetId}`);
revalidateTag('relationships');

Cascade Invalidation

To invalidate related resources:

async function updateEntity(id: string, data: EntityData) {
  await saveEntity(id, data);

  // Invalidate entity page
  revalidateTag(`entity-${id}`);

  // Invalidate list pages
  revalidateTag('entities');

  // Invalidate related pages
  const relationships = await getEntityRelationships(id);
  for (const rel of relationships) {
    revalidateTag(`entity-${rel.targetId}`);
  }
}

Batch Invalidation

To invalidate multiple resources efficiently:

async function bulkUpdateEntities(updates: EntityUpdate[]) {
  await saveBulkUpdates(updates);

  // Collect unique tags
  const tags = new Set<string>(['entities']);
  for (const update of updates) {
    tags.add(`entity-${update.id}`);
  }

  // Revalidate all at once
  for (const tag of tags) {
    revalidateTag(tag);
  }
}

Performance Optimization

Stale-While-Revalidate

To implement SWR pattern:

export const revalidate = 60; // Revalidate every minute
export const dynamic = 'force-static'; // Serve stale while revalidating

Parallel Data Fetching

To fetch data in parallel:

export default async function EntityPage({ params }: { params: { id: string } }) {
  const [entity, relationships, timeline] = await Promise.all([
    fetchEntity(params.id),
    fetchRelationships(params.id),
    fetchTimeline(params.id),
  ]);

  return <EntityDetailView entity={entity} relationships={relationships} timeline={timeline} />;
}

Selective Streaming

To stream only slow components:

export default function EntityPage({ params }: { params: { id: string } }) {
  return (
    <div>
      <EntityHeader id={params.id} /> {/* Fast, no streaming */}
      <Suspense fallback={<RelationshipsSkeleton />}>
        <EntityRelationships id={params.id} /> {/* Slow, stream it */}
      </Suspense>
    </div>
  );
}

Monitoring and Testing

To monitor cache performance:

1. Cache Hit Rates: Track ISR cache hits vs. regenerations
2. Revalidation Frequency: Monitor how often pages regenerate
3. Response Times: Measure time to first byte (TTFB)
4. Stale Serving: Track stale-while-revalidate occurrences

Use Next.js analytics or custom logging:

// middleware.ts
export function middleware(request: NextRequest) {
  const start = Date.now();

  return NextResponse.next({
    headers: {
      'x-response-time': `${Date.now() - start}ms`,
    },
  });
}

Best Practices

1. Start Conservative: Begin with shorter revalidation intervals, increase gradually
2. Use Cache Tags: Prefer tag-based invalidation over path-based
3. Monitor Performance: Track cache hit rates and response times
4. Plan Invalidation: Design invalidation strategy with data mutations
5. Test Edge Cases: Verify behavior with stale data and revalidation
6. Document Decisions: Record why specific intervals were chosen
7. Consider Users: Balance freshness with performance

Troubleshooting

Common issues:

• Stale Data Persisting: Check cache tag implementation and invalidation logic
• Excessive Regeneration: Increase revalidation interval or fix trigger-happy invalidation
• Slow Page Loads: Add streaming for slow components
• Cache Not Working: Verify fetch options and dynamic/static configuration
• Development vs Production: Remember ISR only works in production builds