seyfert/vendor/rest/processRequestHeaders.ts

import { RestManager } from "./restManager.ts";

/** Processes the rate limit headers and determines if it needs to be rate limited and returns the bucket id if available */
export function processRequestHeaders(rest: RestManager, url: string, headers: Headers) {
    let rateLimited = false;

    // GET ALL NECESSARY HEADERS
    const remaining = headers.get("x-ratelimit-remaining");
    const retryAfter = headers.get("x-ratelimit-reset-after");
    const reset = Date.now() + Number(retryAfter) * 1000;
    const global = headers.get("x-ratelimit-global");
    // undefined override null needed for typings
    const bucketId = headers.get("x-ratelimit-bucket") || undefined;

    // IF THERE IS NO REMAINING RATE LIMIT, MARK IT AS RATE LIMITED
    if (remaining === "0") {
        rateLimited = true;

        // SAVE THE URL AS LIMITED, IMPORTANT FOR NEW REQUESTS BY USER WITHOUT BUCKET
        rest.rateLimitedPaths.set(url, {
            url,
            resetTimestamp: reset,
            bucketId,
        });

        // SAVE THE BUCKET AS LIMITED SINCE DIFFERENT URLS MAY SHARE A BUCKET
        if (bucketId) {
            rest.rateLimitedPaths.set(bucketId, {
                url,
                resetTimestamp: reset,
                bucketId,
            });
        }
    }

    // IF THERE IS NO REMAINING GLOBAL LIMIT, MARK IT RATE LIMITED GLOBALLY
    if (global) {
        const retryAfter = headers.get("retry-after");
        const globalReset = Date.now() + Number(retryAfter) * 1000;
        rest.debug(`[REST = Globally Rate Limited] URL: ${url} | Global Rest: ${globalReset}`);
        rest.globallyRateLimited = true;
        rateLimited = true;

        rest.rateLimitedPaths.set("global", {
            url: "global",
            resetTimestamp: globalReset,
            bucketId,
        });

        if (bucketId) {
            rest.rateLimitedPaths.set(bucketId, {
                url: "global",
                resetTimestamp: globalReset,
                bucketId,
            });
        }
    }

    if (rateLimited && !rest.processingRateLimitedPaths) {
        rest.processRateLimitedPaths(rest);
    }
    return rateLimited ? bucketId : undefined;
}