HMAC signature verification for fastify
npm install @autotelic/fastify-hmac
Fastify plugin for HMAC signature validation.
Verifies that http messages are signed according to [IETF draft standards][1].
``shell`
npm i @autotelic/fastify-hmac
Registering the plugin will decorate the fastify request instance with a validateHMAC method, and add a pre-validation hook to verify the HMAC signature of requests.
`js
const hmac = require('@autotelic/fastify-hmac')
async function app (fastify, options) {
fastify.register(hmac, {
sharedSecret: 'topSecret',
algorithmMap: {
hs2019: {
'my-key-a': 'sha512',
'my-key-b': 'sha256'
}
}
})
const hmacLogger = (error) => {
if (error) {
fastify.log.info(error.message)
} else {
fastify.log.info('HMAC Validated.')
}
}
fastify.get('/foo', async (request, reply) => {
request.validateHMAC(hmacLogger)
reply.send({ foo: 'bar' })
})
}
module.exports = app
`
| string | Secret used by client to generate signatures. (required) |
| algorithmMap | { [algorithm]: { [keyId]: string } } | Maps the Signature header algorithm and keyId properties to a specific algorithm. (required, unless providing getAlgorithm) |
| verificationError | (string) => Error | Receives the original error message and returns a new error. By default, all errors returned are generic Unauthenticated http errors. This is to prevent sending sensitive error data to the client. (optional) |
| digestEncoding | string |Defaults to 'base64'. (optional) |
| getDigest | (FastifyRequest, PluginOpts) => string | Calculates and verifies a message Digest header to be used as input to the HMAC signature. (optional) |
| extractSignature | (FastifyRequest, PluginOpts) => string | Extracts properties from the Signature Header constructed according to [IETF draft standards][1]. (optional) |
| constructSignatureString | (FastifyRequest, PluginOpts) => string | Constructs a signature digest string from the key material detailed in the Signature header according to [IETF draft standards][1]. (optional) |
| getAlgorithm | (FastifyRequest, PluginOpts) => string | Returns an HMAC algorithm. By default this will use the keyId and algorithm values from the Signature header, to pull the appropriate value from the algorithmMap. (optional) |
| getSignatureEncoding | (FastifyRequest, PluginOpts) => string | Returns the encoding to be used during HMAC signature construction. (optional - defaults to () => 'base64') |
| validateRequests | boolean | If true will add a preValidation hook to validate HMAC signatures. (optional - defaults to true) |$3
##### Arguments
| Name | Type | Description |
|------|------|-------------|
| callback | (Error?) => any | Called with no args when HMAC validation is successful, and called with the error on failure. (optional) |##### Return
If no callback is provided the
validateHMAC request decorator will return true if HMAC validation is successful, and will return an Error if HMAC validation fails (the Error wil be returned, not thrown).Examples:
#### Basic
`sh
npm run example:basic
`#### Shopify
sh
npm run example:shopify
``MIT
[1]: https://datatracker.ietf.org/doc/draft-ietf-httpbis-message-signatures/