How to use OAuth2 authentication APIs

I've turned on logging and get this in the event log (keys changed to protect the innocent):

AuthHost encountered a navigation error at URL: <https://www.dropbox.com/1/oauth2/authorize?response_type=token&client_id=nfruabcdefg6g64&redirect_uri=http%3A%2F%2Flocalhost%2F&state=ufqdpabcdefgtmy&force_reapprove=true> with HttpStatusCode: 400.

Information: AuthHost encountered Meta Tag: mswebdialog-title with content: <Can't connect to the service>.

Information: AuthHost completed document from URL: <res://authhost.exe/error.html?fgcolor=000000&bgcolor=ffffff>.

Running Fiddler I got this too:

AuthHost encountered a navigation error at URL: <https://www.dropbox.com/1/oauth2/authorize?response_type=token&client_id=nfruabcdefg6g64&redirect_uri=http%3A%2F%2Flocalhost%2F&state=ufqdpabcdefgtmy> with StatusCode: 0x800C0005.

I can't see any of the responses in Fiddler but the error is different in any case so probably not useful.

The UI dialog just shows a "can't connect right now" error and I don't get asked for my credentials.

Changing the Auth Type to "Code" and the redirect Url to null, I do get prompted for my credentials and can get through the auth flow, but at the end it just displays the token on the screen and does not pass it back to my app. Passing a non-null redirect url with "Code" gives me the 400 error again.

Cheers,

Paul

I suspect you could repro the error by creating a blank UWP app and adding the two lines in the original post with your appKey and appSecret.

Cheers,

Paul

Thanks for the quick response, I indeed clicked on the URL and got an error message which was how I figured it out. The trailing slash was being added by the Uri class I think - I was not putting it in but it was getting sent which was confusing and without an error message, hard to isolate.

Cheers,

Paul

By the way, I'm not sure I understand this suggestion:

"things like SearchMode.FilenameAndContent.Instance should be enums that are "or"able"

Can you elaborate? Thanks in advance! 

I just checked and both of the following append the slash to the redirect URL:

                    Uri redirect = new Uri("https://localhost");
                    var authUri = DropboxOAuth2Helper.GetAuthorizeUri(OAuthResponseType.Token, appKey, redirect, state, false, false);

                    var authUri = DropboxOAuth2Helper.GetAuthorizeUri(OAuthResponseType.Token, appKey, "https://localhost", state, false, false);

Perhaps your registration page should suggest adding the trailing slash to avoid others running into this.

Regarding "or"able enums, lets take SearchMode as an example. The current implementation is neither intuitive or scalable. If you want to extend the API in the future with a new field that you can search on, you have to add every permutation of the flags as a definition - SearchMode.Description, SearchMode.FilenameAndDescription, SearchMode.FilenameAndContentAndDescription. These would normally be defined in C# as a Flags enum:

    [Flags]
    public enum SearchMode
    {
        Filename = 1,
        Content = 2,
        Description = 4,
        AnythingElse = 8
    }
           SearchMode mode = SearchMode.Filename | SearchMode.Content;
            if (searchDescription)
                mode |= SearchMode.Description;

A lot of discussion here: http://stackoverflow.com/questions/8447/what-does-the-flags-enum-attribute-mean-in-c

By the way, you can download my app here if you'd like to try it: http://www.modernfileexplorer.com

Cheers,

Paul