Web-hook handling logic help

gagsbh

Hello Greg,

 

I need some help with using Web-hooks.

 

I use the following code to get a cursor token for the Root folder

 

Code I:

result = await client.Files.ListFolderGetLatestCursorAsync("",true);

and I save result.cursor in database.

 

Next time a web-hook arrives for the same dropbox account, I use the result.cursor previously saved in database to get the files changes
in Root folder, since the time I last saved the result.cursor token in database. I use the following code for this.

Code II:
ListFolderResult result2 = await client.Files.ListFolderContinueAsync(lstCursor); //lastCursor is read from database
var firstFile = result2.Entries.FirstOrDefault(i => i.IsFile);
if (firstFile != null)
{
//await Download(client, path, firstFile.AsFile);
}

 

I also update/save the result2.cursor in db so that next time the web-hook comes I use it to get the next set of changes since we got last file changes by using the following code:

Code III:
ListFolderResult result3 = await client.Files.ListFolderContinueAsync(lastCursor); //lastCursor ie. result2.cursor is read from database
var firstFile = result3.Entries.FirstOrDefault(i => i.IsFile);
if (firstFile != null)
{
//await Download(client, path, firstFile.AsFile);
}

 

I need to know whether my handling of web-hooks to get incremental file changes in Root folder is correct. (Please see Code I,II and III)

 

I am getting an exception while processing Case II:
The Exception is: Error in call to API function "files/list_folder/continue": Invalid "cursor" parameter:

 

Please help.

 

Thanks,
Gagan

Greg-DB

In your code for handling the ListFolderContinueAsync result, you appear to only be checking the first entry. That result can contain a large number of entries per page though, so this code could miss a significant number of entries. You should iterate through Entries to make sure you handle everything.

You can find more information on handling the Files.ListFolder* results in the documentation here:

https://dropbox.github.io/dropbox-sdk-dotnet/html/M_Dropbox_Api_Files_Routes_FilesUserRoutes_ListFolderAsync.htm

Regarding the cursor error, I see you have another thread for that, so I answered there:

https://www.dropboxforum.com/t5/API-Support-Feedback/Error-in-call-to-API-function-quot-files-list-folder-continue/m-p/282730#M17315