Check if Dropbox App Folder Exists - php

Question

I am trying to check when users log into my dashboard if they have a connected Dropbox account. I can do this fine, but, I also want to check if the App folder exists in the Dropbox, otherwise users can start uploading files and fail because the path doesn't exist because there is no root. I'd rather catch this at the start then during the upload process.
I was trying to use findErrorNonRoot but the obviously doesn't accept the root.
$pathError = dbx\Path::findErrorNonRoot($dropboxPath);
I also tried isValid
$pathError = dbx\Path::isValid("/");

Answer 1

In case if the user has removed their "App" folder, Dropbox API throws Dropbox\Exception_InvalidAccessToken exception. So you should only handle this exception properly. For example:
use \Dropbox as dbx;
define ('API_CONF_FILE', '/path/to/api-conf.json');
define ('CLIENT_ID', 'Your Upload App/1.0');
$accessToken = obtain_the_access_token();
$appInfo = dbx\AppInfo::loadFromJsonFile(API_CONF_FILE);
for (;;) {
echo "Connecting to Dropbox...\n";
$dbxClient = new dbx\Client($accessToken, CLIENT_ID);
try {
// This call will also throw `Dropbox\Exception_InvalidAccessToken`
//$folderMetadata = $dbxClient->getMetadataWithChildren("/");
$f = fopen("/path/to/test.txt", "r");
$result = $dbxClient->uploadFile("/test.txt", dbx\WriteMode::add(), $f);
fclose($f);
print_r($result);
break;
} catch (Dropbox\Exception_InvalidAccessToken $e) {
$message = $e->getMessage();
if ($brace_pos = strpos($message, '{')) {
$error_title = substr($message, 0, $brace_pos);
if ($json_error = json_decode(substr($message, $brace_pos), true)) {
$error_description = $json_error['error'] ?? 'N/A';
}
fprintf(STDERR, "Error: %s\nDescription: %s\n",
$error_title, $error_description ?? 'N/A');
$webAuth = new dbx\WebAuthNoRedirect($appInfo, CLIENT_ID);
$authorizeUrl = $webAuth->start();
echo "1. Go to: $authorizeUrl\n";
echo "2. Click \"Allow\" (you might have to log in first).\n";
echo "3. Copy the authorization code.\n";
$authCode = \trim(\readline("Enter the authorization code here: "));
list($accessToken, $dropboxUserId) = $webAuth->finish($authCode);
echo "Access Token: $accessToken\n";
}
} catch (Exception $e) {
fprintf(STDERR, "Unknown exception: %s\n", $e->getMessage());
exit(1);
}
}
Note, I've used PHP7 Null coalescing operator.
Sample output (when the folder is initially removed)
Connecting to Dropbox...
Error: HTTP status 401
Description: User has removed their App folder.
1. Go to: https://www.dropbox.com/1/oauth2/authorize?locale=&client_id=2deadbeef2ofaft&response_type=code
2. Click "Allow" (you might have to log in first).
3. Copy the authorization code.
Enter the authorization code here: IugIByIMdKkAAAAAAAAAhVTH02dF7LW70_fFEHHohXo
Access Token: IugIByIMdKkAAAAAAAAAhtPGKSoVOBs557XXrq-zX57L4QRAmqiUTagktS7YDmg1
Connecting to Dropbox...
Array
(
[revision] => 1
[bytes] => 10
[thumb_exists] =>
[rev] => 14ef8952b
[modified] => Tue, 04 Oct 2016 09:02:31 +0000
[mime_type] => text/plain
[path] => /working-draft.txt
[is_dir] =>
[size] => 10 bytes
[root] => app_folder
[id] => id:rmvcpq3LHlAAAAAAAAAAAw
[client_mtime] => Tue, 04 Oct 2016 09:02:31 +0000
[icon] => page_white_text
)
Sample output (when the folder initially exists)
Connecting to Dropbox...
Array
(
[revision] => 2
[bytes] => 10
[thumb_exists] =>
[rev] => 24ef8b68e
[modified] => Tue, 04 Oct 2016 09:18:20 +0000
[mime_type] => text/plain
[path] => /test.txt
[is_dir] =>
[size] => 10 bytes
[root] => app_folder
[id] => id:VMaySA3Ug5AAAAAAAAAABA
[client_mtime] => Tue, 04 Oct 2016 09:18:20 +0000
[icon] => page_white_text
)
The root App folder is created when the user follows the link and clicks on "Allow" button.