Introduction#

  • Create signature v4
  • Send request to bedrock endpoint
  • Parse response chunk by chunk

Here is the full script

bedrock-wo-sdk.js
// https://blog.alu.ai/signing-aws-api-requests-in-node-js-2023-version/
// const { SignatureV4 } = require("@smithy/signature-v4");
import { SignatureV4 } from '@smithy/signature-v4'
import { Sha256 } from '@aws-crypto/sha256-js'
import { HttpRequest } from '@aws-sdk/protocol-http'


const decoder = new TextDecoder()


// const ENDPOINT = "https://bedrock-runtime.us-east-1.amazonaws.com/model/anthropic.claude-v2/invoke";


const ENDPOINT =
  'https://bedrock-runtime.us-east-1.amazonaws.com/model/anthropic.claude-v2/invoke-with-response-stream'


async function signRequest() {
  // create a http request
  // path: /BUCKET-NAME/web-css/osaka-street.jpeg
  // host: s3.us-east-1.amazonaws.com
  const request = new HttpRequest({
    path: new URL(ENDPOINT).pathname,
    hostname: new URL(ENDPOINT).hostname,
    protocol: 'https:',
    method: 'POST',
    headers: {
      host: new URL(ENDPOINT).hostname,
      Accept: 'application/vnd.amazon.eventstream',
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({
      prompt: '\n\nHuman: How to cook chicken soup? \n\nAssistant: ',
      max_tokens_to_sample: 128
    })
  })


  // create a signer using singnaturev4
  const signer = new SignatureV4({
    service: 'bedrock',
    region: 'us-east-1',
    credentials: {
      accessKeyId: '',
      secretAccessKey: '',
      sessionToken: ''
    },
    sha256: Sha256
  })


  const signedRequest = await signer.sign(request, {
    // signingRegion: "us-east-1",
    // signingService: "bedrock",
    // signingDate: new Date(),
    // date: new Date(),
    // expires: new Date(Date.now() + 15 * 60 * 1000), // 15 minutes
    // // list of headers used to compute signature
    // signedHeaders: "host;x-amz-date",
  })


  console.log(signedRequest)


  console.log(`https://${signedRequest.hostname}${signedRequest.path}`)


  const response = await fetch(
    `https://${signedRequest.hostname}${signedRequest.path}`,
    signedRequest
  )


  // const json = await response.json();
  // console.log(json);


  const reader = response.body.getReader()
  const decoder = new TextDecoder('utf-8')


  let answer = ''
  const regex = /\{(.*?)\}/g
  let match


  while (true) {
    const { done, value } = await reader.read()
    if (done) {
      console.log('Done with stream')
      break
    }


    const x = decoder.decode(value)


    try {
      while ((match = regex.exec(x)) !== null) {
        const y = '{' + match[1] + '}'
        const z = atob(JSON.parse(y).bytes)
        console.log(JSON.parse(z).completion)
        answer += JSON.parse(z).completion
      }
    } catch (error) {
      console.log(error)
      answer += 'ERROR'
    }
  }


  console.log(answer)


  // console.log(response.data);
  // fs.writeFileSync("./hehe.jpg", response.data);
  // console.log(signedRequest.headers);
  // console.log(response.data);


  // pipe stream to file
  // response.data.pipe(fs.createWriteStream("./hehe.jpg"));


  // response.data event emitter data chunk
  // response.data.on("data", (chunk) => {
  //   console.log(chunk.length);
  // });
}


// Example usage


const main = async () => {
  await signRequest()
}


main()

And here is package.json

package.json
{
  "name": "nodejs",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "type": "module",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "@aws-crypto/sha256-js": "^5.2.0",
    "@aws-sdk/credential-provider-ini": "^3.529.1",
    "@aws-sdk/protocol-http": "^3.374.0",
    "@smithy/signature-v4": "^2.1.4",
    "axios": "^1.6.7"
  }
}

Create Request#

Let create a request

const ENDPOINT =
  'https://bedrock-runtime.us-east-1.amazonaws.com/model/anthropic.claude-v2/invoke-with-response-stream'


const request = new HttpRequest({
  // path: /cdk-entest-videos/web-css/osaka-street.jpeg
  path: new URL(ENDPOINT).pathname,
  // host: s3.us-east-1.amazonaws.com
  hostname: new URL(ENDPOINT).hostname,
  protocol: 'https:',
  method: 'POST',
  headers: {
    host: new URL(ENDPOINT).hostname,
    Accept: 'application/vnd.amazon.eventstream',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    prompt: '\n\nHuman: How to cook chicken soup? \n\nAssistant: ',
    max_tokens_to_sample: 128
  })
})

Sign Request#

Let create a signature v4 and sign the request

// create a signer using singnaturev4
const signer = new SignatureV4({
  service: 'bedrock',
  region: 'us-east-1',
  credentials: {
    accessKeyId: '',
    secretAccessKey: '',
    sessionToken: ''
  },
  sha256: Sha256
})


const signedRequest = await signer.sign(request, {
  // signingRegion: "us-east-1",
  // signingService: "bedrock",
  // signingDate: new Date(),
  // date: new Date(),
  // expires: new Date(Date.now() + 15 * 60 * 1000), // 15 minutes
  // // list of headers used to compute signature
  // signedHeaders: "host;x-amz-date",
})


console.log(signedRequest)

Parse Response#

In case of streaming response, let parse it chunk by chunk, use regex to detect the completion, the decode the based64.

  • Parse chunk by chunk
  • Regex to capture answer
  • Base64 decode to string
const reader = response.body.getReader()
const decoder = new TextDecoder('utf-8')


let answer = ''
const regex = /\{(.*?)\}/g
let match


while (true) {
  const { done, value } = await reader.read()
  if (done) {
    console.log('Done with stream')
    break
  }


  const x = decoder.decode(value)


  try {
    while ((match = regex.exec(x)) !== null) {
      const y = '{' + match[1] + '}'
      const z = atob(JSON.parse(y).bytes)
      console.log(JSON.parse(z).completion)
      answer += JSON.parse(z).completion
    }
  } catch (error) {
    console.log(error)
    answer += 'ERROR'
  }
}


console.log(answer)

In case of normal response

const json = await response.json()
console.log(json)

Reference#

  • bedrock runtime api docs