Calculate SAPISIDHASH

calc-sapisidhash.js

// Generates the SAPISIDHASH token Google uses in the Authorization header of some API requests
async function getSApiSidHash(SAPISID, origin) {
    function sha1(str) {
      return window.crypto.subtle.digest("SHA-1", new TextEncoder("utf-8").encode(str)).then(buf => {
        return Array.prototype.map.call(new Uint8Array(buf), x=>(('00'+x.toString(16)).slice(-2))).join('');
      });
    }
    
    const TIMESTAMP_MS = Date.now();
    const digest = await sha1(`${TIMESTAMP_MS} ${SAPISID} ${origin}`);

    return `${TIMESTAMP_MS}_${digest}`;
}

const SAPISIDHASH = await getSApiSidHash(document.cookie.split('SAPISID=')[1].split('; ')[0], 'https://photos.google.com');
console.log(SAPISIDHASH);

This has stopped working for me on youtube. document.cookie has no SAPISID key in it.

document.cookie.includes('SAPISID=') // false

Although I can see that the hash is still present in Authorization header of requests made by the browser.