How to generate SHA256 hash for remote files using JavaScript in Zapier workflows

Other Questions Zapier
1

I need to create file checksums in my Zapier automation but ran into issues since the platform doesn’t include built-in hashing functions. After some research, I managed to build a JavaScript solution that works well.

My approach involves:

  1. Download file content from remote URL
  2. Generate SHA256 checksum from the data
  3. Output the hash value for further processing
const hashLib = require('crypto');

return fetch(inputData.remoteFileUrl)
  .then((response) => {
    console.log('Request successful:', response.ok);
    console.log('Status code:', response.status);
    return response.buffer();
  })
  .then((fileBuffer) => {
    const hasher = hashLib.createHash('sha256');
    hasher.update(fileBuffer);
    callback(null, {"fileChecksum": hasher.digest('hex')});
  })
  .catch(callback);

Important considerations:

  • Files must be accessible via public URLs since Zapier only accepts string inputs
  • For sensitive documents, remember to clean up temporary files afterward
  • URLs with special characters (like currency symbols) might cause access errors

This solution works great for document verification workflows where you need to track file integrity.

2

nice solution! just a heads up - fetch().buffer() might not work in newer zapier enviroments. you’ll probably need to use arrayBuffer() instead and convert it. also watch out for file size limits since zapier has memory constraints for code steps.

3

I’ve done something similar and error handling is key with large files or flaky URLs. Your code looks good but add timeout handling and size checks before processing. I always check content-length headers first - saves the workflow from crashing on huge files. Also, some CDNs return weird content types that mess with buffer processing, so validate response headers upfront. Saves tons of debugging later. The crypto module approach is spot on though.

4

Watch out for authentication headers if your remote files need access control. I ran into this with cloud storage that required bearer tokens or API keys. Just add an authorization headers object to your fetch call. Also, wrap the hash generation in try-catch for the crypto operations. Sometimes buffer data gets corrupted during transfer and createHash will fail silently. I wasted hours thinking it was a network problem when it was actually malformed data breaking the hasher.