Add JWT sample

samples/jwt.js

@@ -0,0 +1,46 @@
+import crypto from "k6/crypto";
+import encoding from "k6/encoding";
+import {sleep} from "k6";
+
+const algToHash = {
+    HS256: "sha256",
+    HS384: "sha384",
+    HS512: "sha512"
+};
+
+function sign(data, hashAlg, secret) {
+    let hasher = crypto.createHMAC(hashAlg, secret);
+    hasher.update(data);
+
+    // Some manual base64 rawurl encoding as `Hasher.digest(encodingType)`
+    // doesn't support that encoding type yet.
+    return hasher.digest("base64").replace(/\//g, "_").replace(/\+/g, "-").replace(/=/g, "");
+}
+
+function encode(payload, secret, algorithm) {
+    algorithm = algorithm || "HS256";
+    let header = encoding.b64encode(JSON.stringify({ typ: "JWT", alg: algorithm }), "rawurl");
+    payload = encoding.b64encode(JSON.stringify(payload), "rawurl");
+    let sig = sign(header + "." + payload, algToHash[algorithm], secret);
+    return [header, payload, sig].join(".");
+}
+
+function decode(token, secret, algorithm) {
+    let parts = token.split('.');
+    let header = JSON.parse(encoding.b64decode(parts[0], "rawurl"));
+    let payload = JSON.parse(encoding.b64decode(parts[1], "rawurl"));
+    algorithm = algorithm || algToHash[header.alg];
+    if (sign(parts[0] + "." + parts[1], algorithm, secret) != parts[2]) {
+        throw Error("JWT signature verification failed");
+    }
+    return payload;
+}
+
+export default function() {
+    let message = { key2: "value2" };
+    let token = encode(message, "secret");
+    console.log("encoded", token);
+    let payload = decode(token, "secret");
+    console.log("decoded", JSON.stringify(payload));
+    sleep(1)
+}