alexa-verifier
Version:
Verify HTTP requests sent to an Alexa skill are sent from Amazon
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# alexa-verifier
Verify HTTP requests sent to an Alexa skill are sent from Amazon.
This module is framework-agnostic.
If you're using expressjs, you should check out [alexa-verifier-middleware](https://github.com/alexa-js/alexa-verifier-middleware) which is a lot easier to integrate.
### motivation
Part of the certication process for alexa skills hosted on a generic web service (i.e., not AWS Lambda) is that your skill must validate requests are actually coming from Amazon. This is enforced by checking:
* the timestamp of the request
* the validity of the certificate
* the signature of the the request signed with the aforementioned certificate
This module provides a function to handle this validation.
### usage
arguments
* `cert_url` full url of the certificate to verify (from HTTP request header named `signaturecertchainurl`)
* `signature` signature of the request (from HTTP request header named `signature`)
* `requestRawBody` full body string from POST request
* `callback` (optional) completion function. has 1 argument which indicates error. falsey when verification passes
You may include a callback function, in the standard node error argument-first format:
```javascript
import verifier from 'alexa-verifier'
verifier(cert_url, signature, requestRawBody, function callbackFn (er) {
// if er, something went wrong
})
```
Ommiting a callback function returns a promise:
```javascript
const verifyPromise = verifier(cert_url, signature, requestRawBody)
```