What causes "exec is not supported in Cloudflare Workers" in DIYgod/RSSHub?

Avoid calling exec() in code paths deployed to Workers.

exec is not supported in Cloudflare Workers

Error message

exec is not supported in Cloudflare Workers

What it means

Intentional guard in the Cloudflare Workers shim for node:child_process (lib/shims/node-child-process.ts). The Workers runtime cannot spawn OS processes, so exec() throws immediately when called. Note execSync() is deliberately NOT throwing — it returns an empty Buffer so git-info lookups degrade to 'unknown' instead of crashing.

Source

Thrown at lib/shims/node-child-process.ts:10

// Worker-specific shim for node:child_process
// This module is not available in Cloudflare Workers

export function execSync(_command: string): Buffer {
    // Return empty buffer - git info will fall back to 'unknown'
    return Buffer.from('');
}

export function exec() {
    throw new Error('exec is not supported in Cloudflare Workers');
}

export function spawn() {
    throw new Error('spawn is not supported in Cloudflare Workers');
}

View on GitHub (pinned to bed535e087)

Solutions

Avoid calling exec() in code paths deployed to Workers.
Gate the call behind a runtime check (Node vs Workers) and skip it under Workers.
If a degraded value is acceptable, mirror execSync's pattern: return a safe empty default instead of throwing.
Move the offending route to the Node deployment target.

Example fix

// before
import { exec } from 'node:child_process';
exec('git rev-parse --short HEAD', cb);
// after
import { execSync } from 'node:child_process';
// execSync is shimmed to return '' under Workers
const sha = execSync('git rev-parse --short HEAD').toString().trim() || 'unknown';

Defensive patterns

Strategy: validation

Validate before calling

// detect Workers runtime before any exec() call
const isWorkers =
  typeof navigator !== 'undefined' &&
  (navigator.userAgent?.includes('Cloudflare-Workers') ||
   // @ts-expect-error global only in Workers
   typeof caches !== 'undefined' && typeof process === 'undefined');
if (isWorkers) {
  // skip exec(); fall back to a static/empty value
}

Type guard

function canExec(): boolean {
  return typeof process !== 'undefined' && !!process.versions?.node;
}

Try / catch

try {
  if (canExec()) {
    // real exec only on Node
  } else {
    return ''; // Workers-safe fallback
  }
} catch (e) {
  if (e instanceof Error && /not supported in Cloudflare Workers/.test(e.message)) return '';
  throw e;
}

Prevention

Prefer execSync (shimmed to empty) over exec where a degraded value is fine.
Audit shell-out calls before deploying a route to Workers.
Gate subprocess code behind a Node-runtime check.

When it happens

Trigger: Any code path that calls child_process.exec(...) (async shell-out) while running the Cloudflare Workers build of RSSHub — e.g. a route that runs an external binary, or a transitive dependency that probes the shell.

Common situations: A route written for Node that shells out; Puppeteer-style launch wrappers; a library that runs `git`/`hostname` via exec; deploy target switched from Node to Workers without auditing shell usage.

Related errors

AI-assisted analysis of DIYgod/RSSHub@bed535e087 (2026-08-12). Data as JSON: /api/errors/77d657004c599800. Report an issue: GitHub.