-
-
Notifications
You must be signed in to change notification settings - Fork 310
/
decode_protected_header.ts
51 lines (47 loc) · 1.58 KB
/
decode_protected_header.ts
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
import { decode as base64url } from './base64url.js'
import { decoder } from '../lib/buffer_utils.js'
import isObject from '../lib/is_object.js'
import type { JWSHeaderParameters, JWEHeaderParameters } from '../types.d'
export type ProtectedHeaderParameters = JWSHeaderParameters & JWEHeaderParameters
/**
* Decodes the Protected Header of a JWE/JWS/JWT token utilizing any JOSE serialization.
*
* This function is exported (as a named export) from the main `'jose'` module entry point as well
* as from its subpath export `'jose/decode/protected_header'`.
*
* @example
*
* ```js
* const protectedHeader = jose.decodeProtectedHeader(token)
* console.log(protectedHeader)
* ```
*
* @param token JWE/JWS/JWT token in any JOSE serialization.
*/
export function decodeProtectedHeader(token: string | object): ProtectedHeaderParameters {
let protectedB64u!: unknown
if (typeof token === 'string') {
const parts = token.split('.')
if (parts.length === 3 || parts.length === 5) {
;[protectedB64u] = parts
}
} else if (typeof token === 'object' && token) {
if ('protected' in token) {
protectedB64u = token.protected
} else {
throw new TypeError('Token does not contain a Protected Header')
}
}
try {
if (typeof protectedB64u !== 'string' || !protectedB64u) {
throw new Error()
}
const result = JSON.parse(decoder.decode(base64url(protectedB64u!)))
if (!isObject(result)) {
throw new Error()
}
return <ProtectedHeaderParameters>result
} catch {
throw new TypeError('Invalid Token or Protected Header formatting')
}
}