Flysystem based Dropbox backend for Nextcloud

Requires Nextcloud 26.0 to 30.0

• Install the app from App Store
• Enable the app in the web interface

• Clone the source into the Nextcloud apps directory.
• Set the directory ownership according to your setup.
• Run make or composer install within the apps directory
• Enable the app by running occ app:enable files_external_dropbox from nextcloud main directory

Connecting Dropbox with OAuth 2 is a little more work because you have to create a Dropbox app.

• Log into the Dropbox Developers page and click Create Your App

• Choose if you want to share a single folder or your complete Dropbox with your Nextcloud.

• Name your new app and click "Create app"

• In the tab "Settings" of your Dropbox app

  • If you have chosen to use a single folder, you may want to change the "App folder name"

  • Add new "Redirect URIs" under section "OAuth 2"

    • For adding global storages:

      https://mynextcloud.example.com/index.php/settings/admin/externalstorages

    • For user storages:

      https://mynextcloud.example.com/index.php/settings/user/externalstorages

    Replace https://mynextcloud.example.com/ with your valid Nextcloud installation path

    If you have set htaccess.RewriteBase in your config.php you may need to remove /index.php

    If your Nextcloud is in a subdirectory you need to add this subdirectory here too

• In the tab "Permissions" of your Dropbox app

  • Check all checkboxes under section "Files and folders"
  • If there is a section "Team Scopes", you may want to uncheck all of them, if you do not want to login with a Dropbox work account

• Then go to nextcloud /settings/admin/externalstorages and add a new storage Dropbox V2

  ⚠️ Warning: There is a bug introduced in Nextcloud v24.0.0 but only fixed in v27.0.0 and up.

  This bug prevents any interactive authorisation for external storages like its required for OAuth2,

  but any existing authorization remains in place as long as it is not revoked.

  If you know what you are doing, you may fix it yourself, like it has been done in core version 27.0.0:

  https://github.com/nextcloud/server/commit/da83464459d4fc2fd4965b805354933f8e6fbdf6

  You need to reapply this patch after any update of the files_external app and the Nextcloud core until core version 27.0.0.

• Fill the details "Client ID" and "Client secret" from your Dropbox App page (search for "App key" and "App secret")

• Choose users the external storage should be "Available for"

• Click "Grant access" and then you will be redirected to the OAuth login

• After completing the authorization you will be redirect back to the "External storage" page of yout Nextcloud instance and should see a green mark along your storage configuration

• To allow any user to configure his own Dropbox storage, you need to ensure that the checkbox "Allow users to mount external storage" is checked

This app depends on the flysystem adapter for Dropbox which can be found here:
https://github.com/Hemant-Mann/flysystem-dropbox