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API App Authentication Get List of files/folders from public link

Hi i'm looking for some advice on how to do the following and what best route of authentication / api end points I should use,

I need to be able to parse a dropbox business folder (can do this via a public shared link) for specific files to download which i then need to migrate data to a backoffice system. This would be a background service without user interaction.

What would be the best way to do this with the API and .net SDK?

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Greg-DB

If you have a shared link for a folder and want to programmatically list its contents using the .NET SDK, you should use the ListFolderAsync/ListFolderContinueAsync methods, and supply the 'path' and 'sharedLink' parameters to ListFolderAsync. The 'path' parameter value should be the empty string if you want to list the contents of the folder root itself, or a relative path like "/subfolder" if you want to list the contents of a subfolder.

To download a file from a shared link, you should use the GetSharedLinkFileAsync method. You can supply just the 'url' parameter if the shared link is for the file itself, or both the 'url' and 'path' parameters if the shared link is for a folder and you want to download a specific file, identified by a particular relative path in 'path'.

rsd20

Hi Greg

Thank you for the response. I am struggling to find a way of authenticating without user interaction. As this service will need to run nightly and pull data files from drop box.

Greg-DB

The initial authentication/authorization flow does require manual user interaction, but you can store and re-use the resulting access token after that for future use without further manual user interaction.

rsd20

If i use the access token generated in the app admin console is this sufficient? What lifespan does it have?

Greg-DB

You can use an access token generated from the app's page on the App Console to connect to your own account.

Note that depending on the app's configuration, the access token may be short-lived (expires after four hours) or long-lived (doesn't expire by itself). If you don't yet have the "Access token expiration" option on that page, your access token will be long-lived. You can also tell from the access token itself. If it starts with "sl.", it is short-lived. You can find more information in the OAuth Guide.

rsd20

I understand that the auth code retrieved form manual user interaction can only be used once.

If at this stage I go and get a token anrefresh token. Is it expected to just keep these tokens and keep refreshing as and when I need to. long does the refresh token last?

Is there no way to get a bearer token from just the app key and secret, it seems that the api doesnt cater for background applications?

Greg-DB

The Dropbox API doesn't offer a way to get an access token automatically, just from an app key and secret. If you need "background", sometimes called "offline", access like this, you should get and store the refresh token like you described. The refresh token doesn't expire by itself (though can be revoked on demand), so you can store and re-use that to get new access tokens as needed, without manual user interaction.

tribalneck2000

Is this achievable via the .NET client or only via straight http calls?

Greg-DB

@tribalneck2000 All of the functionality discussed above is available both via the API v2 HTTPS endpoints themselves, as well as the official Dropbox API .NET SDK.

tribalneck2000

Where can I find a sample of exchanging the refresh token for an access token via the .NET API? I have been looking at the repo: https://github.com/dropbox/dropbox-sdk-dotnet

Greg-DB

@tribalneck2000 You can find an example of processing the OAuth flow with the .NET SDK here. For example, it uses the RefreshAccessToken method to use a refresh token to get a new access token here.

tribalneck2000

I think I am misunderstanding what you are saying about offline access - it sounded like you can call the aquire access token once and grab the refresh token and store it permanently since it doesn't expire.. then all you have to do is call RefreshAccessToken after constructing a DropBoxClient with the refresh token as a param (not sure what you are supposed to put in the ctor param for the access token). That doesn't seem to work.

tribalneck2000

Actually I think I got it, read thru the source, there are ctors with just the refresh token. I had a scoping issue that was returning a 400 error. As long as the refresh token can be used forever, I think I may be good for now.

Greg-DB

@tribalneck2000 Thanks for following up. I'm glad to hear you've sorted this out. Yes, refresh tokens don't expire by themselves (though the user or app can revoke them if desired).