Skip to main content

http-content-encoding

This middleware take the preferredEncoding output from @middy/http-content-negotiation and applies the encoding to response.body when a string.

Install​

To install this middleware you can use NPM:

npm install --save @middy/http-content-encoding

Options​

  • br (object) (default {}): zlib.createBrotliCompress brotliOptions
  • gzip (object) (default {}): zlib.createGzip gzipOptions
  • deflate (object) (default {}): zlib.createDeflate deflateOptions
  • overridePreferredEncoding (array[string]) (optional): Override the preferred encoding order, most browsers prefer gzip over br, even though br has higher compression. Default: []

NOTES:

  • Important For br encoding NodeJS defaults to 11. Levels 10 & 11 have been shown to have lower performance for the level of compression they apply. Testing is recommended to ensure the right balance of compression & performance.

Sample usage​

import middy from '@middy/core'
import httpContentNegotiation from '@middy/http-content-negotiation'
import httpContentEncoding from '@middy/http-content-encoding'
import { constants } from 'node:zlib'

export const handler = middy()
  .use(httpContentNegotiation())
  .use(httpContentEncoding({
    br: {
      params: {
        [constants.BROTLI_PARAM_MODE]: constants.BROTLI_MODE_TEXT, // adjusted for UTF-8 text
        [constants.BROTLI_PARAM_QUALITY]: 7
      }
    },
    overridePreferredEncoding: ['br', 'gzip', 'deflate']
  })
  .handler((event, context) => {
    return {
      statusCode: 200,
      body: '{...}'
    }
  })

Using streams​

import middy from '@middy/core'
import httpContentNegotiation from '@middy/http-content-negotiation'
import httpContentEncoding from '@middy/http-content-encoding'
import { constants } from 'node:zlib'
import { createReadableStream } from '@datastream/core'

const lambdaHandler = (event, context) => {
  return {
    statusCode: 200,
    body: createReadableStream('{...}')
  }
}

export const handler = middy({ streamifyResponse: true })
  .use(httpContentNegotiation())
  .use(httpContentEncoding({
    br: {
      params: {
        [constants.BROTLI_PARAM_MODE]: constants.BROTLI_MODE_TEXT, // adjusted for UTF-8 text
        [constants.BROTLI_PARAM_QUALITY]: 7
      }
    },
    overridePreferredEncoding: ['br', 'gzip', 'deflate']
  })
  .handler(lambdaHandler)