Koa Dynamic Routing Options

gistfile1.js

const Koa = require('koa');
const Router = require('@koa/router');

const app = new Koa();
const router = new Router();

console.log('🚀 Koa Dynamic Routing Demo\n');

// =============================================================================
// SOLUTION 1: Static Route (your starting point)
// =============================================================================
router.get('/api/v1/thing/stuff', (ctx) => {
  ctx.body = {
    solution: 1,
    type: 'static',
    message: 'Static route: /api/v1/thing/stuff',
    matched: 'thing/stuff'
  };
});

// =============================================================================
// SOLUTION 2: Basic Dynamic Parameters (thing and stuff are dynamic)
// =============================================================================
router.get('/api/v1/:category/:item', (ctx) => {
  const { category, item } = ctx.params;
  ctx.body = {
    solution: 2,
    type: 'basic-dynamic',
    message: `Dynamic route with 2 parameters`,
    params: { category, item },
    path: `${category}/${item}`
  };
});

// =============================================================================
// SOLUTION 3: Custom Middleware for Unlimited Segments
// =============================================================================
const multiSegmentMatcher = (ctx, next) => {
  const path = ctx.path;
  const apiV2Match = path.match(/^\/api\/v2\/(.+)$/);
  
  if (apiV2Match) {
    const segments = apiV2Match[1].split('/').filter(s => s.length > 0);
    
    ctx.multiSegment = {
      solution: 3,
      type: 'unlimited-segments',
      message: 'Custom middleware handling unlimited segments',
      segments,
      segmentCount: segments.length,
      interpretation: {
        category: segments[0] || null,
        item: segments[1] || null,
        additional: segments.slice(2)
      }
    };
  }
  
  return next();
};

router.get(/^\/api\/v2\/(.+)$/, multiSegmentMatcher, (ctx) => {
  ctx.body = ctx.multiSegment || { error: 'No match found' };
});

// =============================================================================
// SOLUTION 4: Pure Regex Route Matching
// =============================================================================
router.get(/^\/api\/v3\/([^\/]+)\/([^\/]+)(?:\/(.*))?$/, (ctx) => {
  const category = ctx.params[0];
  const item = ctx.params[1];
  const additional = ctx.params[2];
  
  ctx.body = {
    solution: 4,
    type: 'regex-matching',
    message: 'Pure regex route with optional additional segments',
    params: { category, item },
    additional: additional ? additional.split('/').filter(s => s.length > 0) : [],
    fullPath: `${category}/${item}${additional ? '/' + additional : ''}`
  };
});

// =============================================================================
// SOLUTION 5: Layered Approach (multiple routes, most specific first)
// =============================================================================
router.get('/api/v4/:category/:item/:extra1/:extra2', (ctx) => {
  const { category, item, extra1, extra2 } = ctx.params;
  ctx.body = {
    solution: 5,
    type: 'layered-4-segments',
    message: 'Matched 4-segment pattern',
    segments: [category, item, extra1, extra2]
  };
});

router.get('/api/v4/:category/:item/:extra1', (ctx) => {
  const { category, item, extra1 } = ctx.params;
  ctx.body = {
    solution: 5,
    type: 'layered-3-segments',
    message: 'Matched 3-segment pattern',
    segments: [category, item, extra1]
  };
});

router.get('/api/v4/:category/:item', (ctx) => {
  const { category, item } = ctx.params;
  ctx.body = {
    solution: 5,
    type: 'layered-2-segments',
    message: 'Matched 2-segment pattern (fallback)',
    segments: [category, item]
  };
});

// =============================================================================
// SOLUTION 6: Simple Catch-All Test
// =============================================================================
router.get('/api/v5/:param1/(.*)', (ctx) => {
  const param1 = ctx.params.param1;
  const param2 = ctx.params[0]; // The catch-all captures everything after param1
  console.log(ctx.params);
  
  ctx.body = {
    solution: 6,
    type: 'simple-catch-all',
    message: 'Simple catch-all with standard Koa routing',
    param1,
    param2,
    params: ctx.params
  };
});

// =============================================================================
// Demo Routes & Documentation
// =============================================================================
router.get('/', (ctx) => {
  ctx.body = {
    title: 'Koa Dynamic Routing Demo - Multiple Solutions',
    solutions: [
      {
        id: 1,
        name: 'Static Route',
        example: '/api/v1/thing/stuff',
        description: 'Your original fixed route'
      },
      {
        id: 2,
        name: 'Basic Dynamic',
        example: '/api/v1/books/fiction',
        description: 'Making thing/stuff dynamic'
      },
      {
        id: 3,
        name: 'Unlimited Segments (Middleware)',
        example: '/api/v2/books/fiction/mystery/agatha-christie',
        description: 'Custom middleware for any number of segments'
      },
      {
        id: 4,
        name: 'Regex Matching',
        example: '/api/v3/books/fiction/mystery/author',
        description: 'Pure regex with optional additional segments'
      },
      {
        id: 5,
        name: 'Layered Routes',
        examples: [
          '/api/v4/books/fiction',
          '/api/v4/books/fiction/mystery',
          '/api/v4/books/fiction/mystery/author'
        ],
        description: 'Multiple routes, most specific matches first'
      }
    ]
  };
});

app.use(router.routes());
app.use(router.allowedMethods());

const PORT = 3000;
app.listen(PORT, () => {
  console.log(`✅ Server running on http://localhost:${PORT}`);
  console.log('\n📋 Test these URLs:');
  console.log('• http://localhost:3000/ (documentation)');
  console.log('• http://localhost:3000/api/v1/thing/stuff (static original)');
  console.log('• http://localhost:3000/api/v1/books/fiction (basic dynamic)');
  console.log('• http://localhost:3000/api/v2/books/fiction/mystery/author (unlimited)');
  console.log('• http://localhost:3000/api/v3/books/fiction/mystery/author (regex)');
  console.log('• http://localhost:3000/api/v4/books/fiction (layered 2-seg)');
  console.log('• http://localhost:3000/api/v4/books/fiction/mystery (layered 3-seg)');
  console.log('• http://localhost:3000/api/v4/books/fiction/mystery/author (layered 4-seg)');
});