plugin.js

const crypto = require('crypto')
const { URL } = require('url')

module.exports.templateTags = [
  {
    name: 'httpsignature',
    displayName: 'HTTP Signature',
    description: 'sign http requests',

    args: [
      {
        displayName: 'Key ID',
        type: 'string',
      },
      {
        displayName: 'Private Key',
        type: 'string',
      },
    ],

    async run(context, keyId, privateKey) {
      const request = await context.util.models.request.getById(
        context.meta.requestId
      )
      const requestUrl = await context.util.render(request.url)

      if (!keyId) throw new Error('missing keyId')
      if (!privateKey) throw new Error('missing privateKey')

      const parsedUrl = new URL(requestUrl)
      for (const parameter of request.parameters) {
        if (!parameter.disabled)
          parsedUrl.searchParams.append(parameter.name, parameter.value)
      }

      const algorithmBits = 256
      const signAlgorithm = `RSA-SHA${algorithmBits}`

      const signatureString = []
      signatureString.push(
        `(request-target): ${request.method.toLowerCase()} ${
          parsedUrl.pathname
        }${parsedUrl.search}`
      )
      signatureString.push(`host: ${parsedUrl.host}`)
      const signature = signatureString.join('\n')

      const signatureSign = crypto.createSign(signAlgorithm)
      const signedSignature = signatureSign
        .update(signature)
        .sign(
          `-----BEGIN RSA PRIVATE KEY-----\n${privateKey}\n-----END RSA PRIVATE KEY-----`,
          'base64'
        )

      const authorization = `keyId="${keyId}", algorithm="${signAlgorithm.toLowerCase()}", headers="(request-target) host", signature="${signedSignature}"`
      return authorization
    },
  },
]