dnb-api/src/aika/headerbuilder.OLD.js

Client for DNB Open Banking platform

const {HeaderBuilder} = require('aika')

const crypto = require('crypto')

module.exports = (options) => {
	return new HeaderBuilder({
		constants: {
			apiKey: options.apiKey,
			clientId: options.clientId,
			clientSecret: options.clientSecret,

			hostName: options.hostName,

			// Reference to client JWT
			token: options.token,

			// Amz
			algorithm: 'AWS4-HMAC-SHA256',
			signedHeaders: 'host;x-amz-date',
			awsRegion: options.awsRegion,
			awsService: options.awsService
		},

		helpers: {
			// Basics
			hashHex: string => crypto.createHash('sha256').update(string, 'utf8').digest('hex'),
			createAmzDate: () => new Date().toISOString().replace(/[:-]|\.\d{3}/g, ''),
			signData: (key, data, encoding) => crypto.createHmac('sha256', key).update(data, 'utf8').digest(encoding ? encoding : 'hex'),

			// Canonical
			canonicalUri: path => {
				const queryStringMatch = path.match(/(.*)\?/)
				let canonicalUri = path

				if (queryStringMatch !== null) {
					const firstMatchIndex = 1
					canonicalUri = queryStringMatch[firstMatchIndex]
				}

				return canonicalUri
			},
			canonicalHeaders: (hostName, amzDate) => `host:${hostName}\nx-amz-date:${amzDate}\n`,
			canonicalRequest: (method, canonicalUri, canonicalQuerystring, canonicalHeaders, signedHeaders, payloadHash) => {
				return `${method}\n${canonicalUri}\n${canonicalQuerystring}\n${canonicalHeaders}\n${signedHeaders}\n${payloadHash}`
			},

			// Credential
			credentialScope: (dateStamp, region, service) => `${dateStamp}/${region}/${service}/aws4_request`,
			credentialHeader: (clientId, credentialScope) => `Credential=${clientId}/${credentialScope}`,

			signedHeaders: () => 'host;x-amz-date',

			getSignatureKey: (context, clientSecret, dateStamp, serviceName, regionName) => {
				const date = context.helpers.signData((`AWS4${clientSecret}`), dateStamp)
				const region = context.helpers.signData(date, regionName)
				const service = context.helpers.signData(region, serviceName)
				return context.helpers.signData(service, 'aws4_request')
			},

			stringToSign: (context, algorithm, amzDate, credentialScope, canonicalRequest) => `${algorithm}\n${amzDate}\n${credentialScope}\n${context.helpers.hashHex(canonicalRequest)}`,
		},

		headerFunctions: {
			Host: c => c.constants.hostName,
			Accept: () => 'application/json',
			'Content-type': () => 'application/json',
			'x-api-key': c => c.constants.apiKey,
			'x-amz-date': c => c.helpers.createAmzDate(),
			//'x-dnbapi-jwt': c => c.constants.token.jwt,
			Authorization: (c, r) => {

				const amzDate = c.helpers.createAmzDate()
				const dateStamp = amzDate.substr(0, 8)

				const signedHeaders = c.constants.signedHeaders
				const payloadHash = c.helpers.hashHex(r.body ? JSON.stringify(r.body) : '')

				// Canonical
				const canonicalUri = c.helpers.canonicalUri(r.path)
				const canonicalQuerystring = r.params
				const canonicalHeaders = c.helpers.canonicalHeaders(c.constants.hostName, amzDate)
				const canonicalRequest = c.helpers.canonicalRequest(
					r.method,
					canonicalUri,
					canonicalQuerystring,
					canonicalHeaders,
					signedHeaders,
					payloadHash
				)


				// 
				const credentialScope = c.helpers.credentialScope(dateStamp, c.constants.awsRegion, c.constants.awsService)
				const signingKey = c.helpers.getSignatureKey(
					c,
					c.constants.clientSecret,
					dateStamp,
					c.constants.awsService,
					c.constants.awsRegion
				)
				const stringToSign = c.helpers.stringToSign(
					c,
					c.constants.algorithm,
					amzDate,
					credentialScope,
					canonicalRequest
				)

				// Final
				const credentialHeader = c.helpers.credentialHeader(c.constants.clientId, credentialScope)
				const signature = c.helpers.signData(signingKey, stringToSign, 'hex')

				console.log('Canonical string:\n', canonicalRequest)
				console.log('String to sign:\n', stringToSign)

				return `${c.constants.algorithm} ${credentialHeader}, SignedHeaders=${signedHeaders}, Signature=${signature}`
			},
		}
	})
}