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Compression Guide

Learn how to compress and decompress data in your Invoke functions.

Overview​

import zlib from 'zlib'

export default function handler(req, res) {
  const data = 'Hello World! '.repeat(100)
  const compressed = zlib.gzipSync(data)
  const decompressed = zlib.gunzipSync(compressed)

  res.json({
    original: data.length,
    compressed: compressed.length,
    ratio: ((compressed.length / data.length) * 100).toFixed(2) + '%'
  })
}

Gzip Compression​

Synchronous​

import zlib from 'zlib'

export default function handler(req, res) {
  const data = 'Hello World! '.repeat(100)
  const compressed = zlib.gzipSync(data)
  const decompressed = zlib.gunzipSync(compressed)

  res.json({
    original: data.length,
    compressed: compressed.length,
    ratio: ((compressed.length / data.length) * 100).toFixed(2) + '%',
    decompressed: decompressed.toString()
  })
}

Streaming​

import zlib from 'zlib'
import { Readable } from 'stream'

export default async function handler(req, res) {
  const chunks = []
  const source = Readable.from(['chunk 1 ', 'chunk 2 ', 'chunk 3'])
  const gzip = zlib.createGzip()

  for await (const chunk of source.pipe(gzip)) {
    chunks.push(chunk)
  }

  const compressed = Buffer.concat(chunks)
  res.setHeader('Content-Encoding', 'gzip')
  res.setHeader('Content-Type', 'text/plain')
  res.send(compressed)
}

Deflate Compression​

import zlib from 'zlib'

export default function handler(req, res) {
  const data = Buffer.from(req.body.data)
  const compressed = zlib.deflateSync(data)
  const decompressed = zlib.inflateSync(compressed)

  res.json({
    original: data.length,
    compressed: compressed.length,
    decompressed: decompressed.toString()
  })
}

Brotli Compression​

import zlib from 'zlib'

export default function handler(req, res) {
  const data = 'Large data...'.repeat(1000)
  const compressed = zlib.brotliCompressSync(data)
  const decompressed = zlib.brotliDecompressSync(compressed)

  res.json({
    original: data.length,
    compressed: compressed.length,
    ratio: ((compressed.length / data.length) * 100).toFixed(2) + '%'
  })
}

Compressing JSON​

import zlib from 'zlib'

export default async function handler(req, res) {
  const data = {
    users: Array.from({ length: 1000 }, (_, i) => ({
      id: i,
      name: `User ${i}`,
      email: `user${i}@example.com`
    }))
  }

  const json = JSON.stringify(data)
  const compressed = zlib.gzipSync(json)

  await kv.set('users:compressed', compressed.toString('base64'))

  res.json({
    originalSize: json.length,
    compressedSize: compressed.length,
    savings: ((1 - compressed.length / json.length) * 100).toFixed(2) + '%'
  })
}

Decompressing JSON​

import zlib from 'zlib'

export default async function handler(req, res) {
  const compressedBase64 = await kv.get('users:compressed')
  const compressed = Buffer.from(compressedBase64, 'base64')
  const decompressed = zlib.gunzipSync(compressed)

  res.json(JSON.parse(decompressed.toString()))
}

HTTP Response Compression​

import zlib from 'zlib'

export default function handler(req, res) {
  const data = { message: 'Large response data...' }
  const json = JSON.stringify(data)
  const acceptEncoding = req.get('Accept-Encoding') || ''

  if (acceptEncoding.includes('gzip')) {
    const compressed = zlib.gzipSync(json)
    res.setHeader('Content-Encoding', 'gzip')
    res.setHeader('Content-Type', 'application/json')
    res.send(compressed)
  } else {
    res.json(data)
  }
}

Compression Levels​

import zlib from 'zlib'

export default function handler(req, res) {
  const data = 'Data to compress'.repeat(100)
  const results = {}

  for (let level = 0; level <= 9; level++) {
    const compressed = zlib.gzipSync(data, { level })
    results[`level_${level}`] = {
      size: compressed.length,
      ratio: ((compressed.length / data.length) * 100).toFixed(2) + '%'
    }
  }

  res.json(results)
}

Best Compression Algorithm Comparison​

import zlib from 'zlib'

export default function handler(req, res) {
  const data = req.body.data || 'Test data'.repeat(1000)
  const gzipped = zlib.gzipSync(data)
  const deflated = zlib.deflateSync(data)
  const brotli = zlib.brotliCompressSync(data)

  res.json({
    original: data.length,
    gzip: { size: gzipped.length, ratio: ((gzipped.length / data.length) * 100).toFixed(2) + '%' },
    deflate: { size: deflated.length, ratio: ((deflated.length / data.length) * 100).toFixed(2) + '%' },
    brotli: { size: brotli.length, ratio: ((brotli.length / data.length) * 100).toFixed(2) + '%' }
  })
}

Error Handling​

import zlib from 'zlib'

export default function handler(req, res) {
  try {
    const compressed = Buffer.from(req.body.data, 'base64')
    const decompressed = zlib.gunzipSync(compressed)
    res.send(decompressed.toString())
  } catch (error) {
    if (error.code === 'Z_DATA_ERROR') {
      res.status(400).json({ error: 'Invalid compressed data' })
    } else {
      res.status(500).json({ error: 'Decompression failed' })
    }
  }
}

Use Cases​

1. Compressing Large KV Store Values​

import zlib from 'zlib'

export default async function handler(req, res) {
  const largeData = {
    /* large object */
  }
  const compressed = zlib.gzipSync(JSON.stringify(largeData))
  await kv.set('large:data', compressed.toString('base64'))
  res.json({ stored: true })
}

2. API Response Caching​

import zlib from 'zlib'

export default async function handler(req, res) {
  const cacheKey = 'api:response'
  const cached = await kv.get(cacheKey)

  if (cached) {
    const decompressed = zlib.gunzipSync(Buffer.from(cached, 'base64'))
    return res.json(JSON.parse(decompressed.toString()))
  }

  const response = await fetch('https://api.example.com/large-data')
  const data = await response.json()
  const compressed = zlib.gzipSync(JSON.stringify(data))

  await kv.set(cacheKey, compressed.toString('base64'), 3600000)
  res.json(data)
}

Best Practices​

1. Choose Right Algorithm​

  • Gzip: Best balance, wide support
  • Deflate: Similar to gzip, less overhead
  • Brotli: Best compression, slightly slower

2. Consider Compression Level​

LevelBun (zlib)C# (CompressionLevel)
Fastlevel: 1Fastest
Defaultlevel: 6Optimal
Bestlevel: 9SmallestSize

3. Only Compress Large Data​

if (data.length > 1024) {
  compressed = zlib.gzipSync(data)
}

Next Steps​