How to transfer base64 image from client to server or download binary / base64 from s3 bucket?

Question

In my app, i'm sending photos directly from the client to s3, using something similar to this suggested heroku recommendation: https://devcenter.heroku.com/articles/s3-upload-node

The main benefit is that it saves server cost (i'm assuming since chunks aren't being sent to the server using something such as multipart-y form data).

However, I wish to be able to share these images to twitter also, which states this requirement:

Ensure the POST is a multipart/form-data request. Either upload the raw binary (media parameter) of the file, or its base64-encoded contents (media_data parameter). Use raw binary when possible, because base64 encoding results in larger file sizes

I've tried sending the base64 needed for the client-side s3 upload back to the server, but depending on the photo size -- I often get an error that it's too big to send back.

TLDR

Do I need to send my photos using mulitparty / multipart form data to my server, so I can have the needed base64 / binary to share a photo to twitter, or can I keep sending photos from my client to s3?

Then, somehow, efficiently obtain the needed base64 / binary on the server (possibly using the request module), so I can then send the image to twitter?

Answer 1

One fairly easy way to do this without changing your client code a whole lot would be to use S3 events. S3 events can trigger a lambda function in AWS that can post the image to twitter. You can use any library inside the lambda function to do efficient posting to twitter. Not sure if you want to use Lambda or stick to Heroku.