1) Use getFile to get the file content and pass it down to the browser instead of saving it to disk. You'll still need to supply a valid resource as the $outStream parameter where the SDK can write the data though. How exactly you set that up it outside the scope of Dropbox API support, and may depend on your web framework, so I can't offer much insight there.
In case this might be of help to others, I decided to use the sdk suggested route and save to web server using a temp file, which I create with a new stream for the getFile method. After downloading the file I then clear the file.
We love to learn from the educators who use Dropbox. Whether you teach kids, teens, adults or a combination of all three, we want to know what apps and integrations you use with Dropbox to help with teaching. Which of the ones below is your favorite, or most used tool?