Dataweave JWT Creation

jwt.dwl

%dw 2.0
import HMACBinary from dw::Crypto
import toBase64 from dw::core::Binaries

fun binaryJson(obj: Object) =
    write(obj, 'application/json', { indent: false }) as Binary

fun base64URL(str: Binary) =
    toBase64(str) replace "+" with "-" replace "/" with "_" replace "=" with ""

fun base64Obj(obj: Object) =
    base64URL(binaryJson(obj))

/** basic JWT with header and payload, no signing */
fun JWT(header: Object, payload: Object) =
    "$(base64Obj(header)).$(base64Obj(payload))"

/** basic JWT with no user specified header */
fun JWT(payload: Object) =
    JWT({typ:'JWT'}, payload)

fun signJWT(content: String, key: String, alg) =
    base64URL(HMACBinary(key as Binary, content as Binary, alg))

/** JWT with header, payload, and signature by specific algorithm. valid algorithms dictated by HMACWith */
fun JWT(header: Object, payload: Object, signingKey: String, algorithm: String) = do {
    var jwt = JWT(header, payload)
    ---
    "$(jwt).$(signJWT(jwt, signingKey, algorithm))"
}

/** JWT with header, payload, and signed with HMAC-SHA256*/
fun JWT(header: Object, payload: Object, signingKey: String) = do {
    JWT({ (header - 'alg' - 'typ'), typ: 'JWT', alg: 'HS256' }, payload, signingKey, 'HmacSHA256')
}

/** JWT with payload and automatically generated header, signed with HMAC-SHA256 */
fun JWT(payload: Object, signingKey: String) =
    JWT({ typ: 'JWT', alg: 'HS256'}, payload, signingKey, 'HmacSHA256')

Usage:

JWT({ email: 'someone@something.com', campaignId: 890283e40e }, "signingKey")