Converting binary response to PDF file format in Code by Zapier using fetch API

Other Questions Zapier
1

I’m working with an API endpoint that returns PDF documents and requires authentication. Here’s my current setup:

var documentEndpoint = 'https://api.example.com/reports/abcd/downloads/efgh.pdf';

var downloadRequest = fetch(documentEndpoint, {
    method: 'GET',
    headers: {
        'Authorization': 'Bearer xyz789token456'
    }
})
.then(function(response) {
    return response;
});

The API call works fine and I receive the document data in binary format. My problem is figuring out how to properly convert this binary response back into a usable PDF file. After that conversion, I want to automatically upload the resulting PDF to cloud storage services like Dropbox or Google Drive. What’s the correct approach to handle the binary data conversion and subsequent file upload process?

2

Deal with this every week. PDF conversion and cloud uploads are a nightmare to maintain.

I used to code all the fetch/conversion stuff myself - ArrayBuffers, blobs, base64, error handling for different APIs. Plus maintaining upload formats for each service. Huge pain.

Now I route authenticated PDF requests through a workflow that handles everything automatically. Grabs the PDF with your auth headers, processes the binary data, and uploads straight to any cloud storage.

No more debugging binary issues or memory problems with large files. Handles auth failures, corrupted PDFs, and different API formats without custom code.

Running this across multiple projects now - invoice APIs, report generators, document services. Set it once, done.

3

just use response.blob() instead of arrayBuffer - way simpler. create a FormData object and append the blob with a filename. works perfectly for Dropbox API uploads without all that base64 conversion stuff. saves you tons of code.

4

You shouldn’t be writing all that binary conversion code manually - it’s such a common workflow.

I handle this exact thing constantly at work. PDFs from authenticated APIs, format conversions, pushing to different storage. The manual arrayBuffer and base64 approach works but it’s a nightmare to maintain.

Instead, I set up automation that handles everything. Fetch the PDF with auth headers, auto-convert the binary response, then push straight to Dropbox or Google Drive. No conversion logic needed.

Best part? You can trigger this from Zapier or anywhere else, and it processes all the binary data behind the scenes. No more Uint8Arrays or btoa functions.

I’ve built dozens of these document workflows - they’re rock solid. Set it up once, done.

Check out Latenode for this: https://latenode.com

5

Add a response.ok check like others said, but also set proper headers when uploading. Most cloud APIs need Content-Type: application/pdf and correct file size headers. I grab content-length from the original response and pass it through - prevents upload errors.

6

Been dealing with this exact problem for months in production. Everyone misses the main thing - you’ve got to handle the response stream right before trying any conversions. Your code’s returning the raw response object instead of actually processing the binary data.

What works for me: check response status first, then use response.arrayBuffer() for the binary data. Just watch your memory usage with big PDFs. I’ve crashed apps processing multiple large docs at once because arrayBuffer dumps everything into memory.

Cloud uploads are tricky - each service wants different formats. Google Drive API likes direct binary data with multipart uploads. Dropbox’s more flexible with base64. The real pain is error handling when the API sends back non-PDF stuff or auth fails. Always validate the content-type header before converting anything.

One thing that saved me - add error boundaries around the conversion process. PDFs get corrupted during transmission all the time, and you want to catch that early instead of pushing garbage files to storage.

7

You’re missing the step where you convert the response to the right format. After your fetch call, use response.arrayBuffer() or response.blob() to handle the binary PDF data properly. Here’s what worked for me:

var downloadRequest = fetch(documentEndpoint, {
    method: 'GET',
    headers: {
        'Authorization': 'Bearer xyz789token456'
    }
})
.then(function(response) {
    return response.arrayBuffer();
})
.then(function(arrayBuffer) {
    // Convert to base64 for storage/upload
    var bytes = new Uint8Array(arrayBuffer);
    var binary = '';
    for (var i = 0; i < bytes.byteLength; i++) {
        binary += String.fromCharCode(bytes[i]);
    }
    return btoa(binary);
});

Then you can upload the base64 result directly to cloud storage. Most cloud APIs take base64 data straight up, which makes uploads way easier. Just remember to set the right content type when uploading.

8

The problem is you’re not processing the binary response correctly. You’re just returning the raw response object instead of extracting the actual PDF data. I’ve hit this same issue with authenticated PDF APIs. Here’s what fixed it for me - use response.blob() with the File API to create a proper file object: javascript var downloadRequest = fetch(documentEndpoint, { method: 'GET', headers: { 'Authorization': 'Bearer xyz789token456' } }) .then(function(response) { if (!response.ok) throw new Error('Download failed'); return response.blob(); }) .then(function(blob) { var file = new File([blob], 'document.pdf', {type: 'application/pdf'}); return file; }); This creates a proper File object that cloud storage APIs can work with directly. I’ve used this successfully with Google Drive and Dropbox uploads - no base64 conversion needed. The File constructor handles all the binary data formatting automatically, which cuts out most of the conversion headaches.