Function mintAppJwt

shared/github/app-auth.ts:135–149

Mint a short-lived App JWT (valid ~9 min, iat backdated for clock skew).

(creds: GithubAppCredentials)

/** Mint a short-lived App JWT (valid ~9 min, iat backdated for clock skew). */
async function mintAppJwt(creds: GithubAppCredentials): Promise<string> {
    const key = await importSigningKey(creds.privateKey);
    const nowSec = Math.floor(Date.now() / 1000);
    const header = { alg: "RS256", typ: "JWT" };
    const payload = { iat: nowSec - 60, exp: nowSec + 540, iss: creds.appId };
    const signingInput = `${b64urlFromString(JSON.stringify(header))}.${b64urlFromString(
        JSON.stringify(payload),
    )}`;
    const sig = await crypto.subtle.sign(
        "RSASSA-PKCS1-v1_5",
        key,
        new TextEncoder().encode(signingInput),
    );
    return `${signingInput}.${b64urlFromBytes(new Uint8Array(sig))}`;
}

async function appJsonGet<T>(path: string, jwt: string): Promise<T> {
    const res = await fetch(`${GITHUB_API}${path}`, {