azure-devops-mcp
by RyanCardin15
Verified
let crypto;
crypto = globalThis.crypto; // web browsers
/**
* Creates an array of length `size` of random bytes
* @param size
* @returns Array of random ints (0 to 255)
*/
function getRandomValues(size) {
return crypto.getRandomValues(new Uint8Array(size));
}
/** Generate cryptographically strong random string
* @param size The desired length of the string
* @returns The random string
*/
function random(size) {
const mask = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-._~";
let result = "";
const randomUints = getRandomValues(size);
for (let i = 0; i < size; i++) {
// cap the value of the randomIndex to mask.length - 1
const randomIndex = randomUints[i] % mask.length;
result += mask[randomIndex];
}
return result;
}
/** Generate a PKCE challenge verifier
* @param length Length of the verifier
* @returns A random verifier `length` characters long
*/
function generateVerifier(length) {
return random(length);
}
/** Generate a PKCE code challenge from a code verifier
* @param code_verifier
* @returns The base64 url encoded code challenge
*/
export async function generateChallenge(code_verifier) {
const buffer = await crypto.subtle.digest("SHA-256", new TextEncoder().encode(code_verifier));
// Generate base64url string
// btoa is deprecated in Node.js but is used here for web browser compatibility
// (which has no good replacement yet, see also https://github.com/whatwg/html/issues/6811)
return btoa(String.fromCharCode(...new Uint8Array(buffer)))
.replace(/\//g, '_')
.replace(/\+/g, '-')
.replace(/=/g, '');
}
/** Generate a PKCE challenge pair
* @param length Length of the verifer (between 43-128). Defaults to 43.
* @returns PKCE challenge pair
*/
export default async function pkceChallenge(length) {
if (!length)
length = 43;
if (length < 43 || length > 128) {
throw `Expected a length between 43 and 128. Received ${length}.`;
}
const verifier = generateVerifier(length);
const challenge = await generateChallenge(verifier);
return {
code_verifier: verifier,
code_challenge: challenge,
};
}
/** Verify that a code_verifier produces the expected code challenge
* @param code_verifier
* @param expectedChallenge The code challenge to verify
* @returns True if challenges are equal. False otherwise.
*/
export async function verifyChallenge(code_verifier, expectedChallenge) {
const actualChallenge = await generateChallenge(code_verifier);
return actualChallenge === expectedChallenge;
}