From what I see in the API it is possible to do this. You need to download the Dropbox Core API. Inside the zip file, you will find an example folder with example code for authentication, upload, download, direct-link and so on. Just see the direct-link.php
and change it to your needs. Here is a tested working example of uploading a file and generating a direct link for download:
<?php
require_once "dropbox-php-sdk-1.1.2/lib/Dropbox/autoload.php";
use \Dropbox as dbx;
$dropbox_config = array(
'key' => 'your_key',
'secret' => 'your_secret'
);
$appInfo = dbx\AppInfo::loadFromJson($dropbox_config);
$webAuth = new dbx\WebAuthNoRedirect($appInfo, "PHP-Example/1.0");
$authorizeUrl = $webAuth->start();
echo "1. Go to: " . $authorizeUrl . "<br>";
echo "2. Click \"Allow\" (you might have to log in first).<br>";
echo "3. Copy the authorization code and insert it into $authCode.<br>";
$authCode = trim('DjsR-iGv4PAAAAAAAAAAAbn9snrWyk9Sqrr2vsdAOm0');
list($accessToken, $dropboxUserId) = $webAuth->finish($authCode);
echo "Access Token: " . $accessToken . "<br>";
$dbxClient = new dbx\Client($accessToken, "PHP-Example/1.0");
// Uploading the file
$f = fopen("working-draft.txt", "rb");
$result = $dbxClient->uploadFile("/working-draft.txt", dbx\WriteMode::add(), $f);
fclose($f);
print_r($result);
// Get file info
$file = $dbxClient->getMetadata('/working-draft.txt');
// sending the direct link:
$dropboxPath = $file['path'];
$pathError = dbx\Path::findError($dropboxPath);
if ($pathError !== null) {
fwrite(STDERR, "Invalid <dropbox-path>: $pathError\n");
die;
}
// The $link is an array!
$link = $dbxClient->createTemporaryDirectLink($dropboxPath);
// adding ?dl=1 to the link will force the file to be downloaded by the client.
$dw_link = $link[0]."?dl=1";
echo "Download link: ".$dw_link."<br>";
?>
I made this really fast just to get it working. Eventually you may need to tweak it a bit so it will suite your needs.