Accept ToS during login flow v2

[tobiasKaminsky]

• have an user that needs to accept ToS
• login via login flow v2 on Desktop/mobile
• login works and file listing on Android works (bug!) propfind still works with 207 #990

Instead it would be best to let user accept ToS before grant access

[max-nextcloud]

Docs for login flow v2

...we have come up with a second login flow that uses the users default webbrowser to authenticate. Thus ensuring that if they can login via the web they can also login in the client.

To initiate a login do an anonymous POST request

curl -X POST https://cloud.example.com/index.php/login/v2

This will return a json object like

{
   "poll":{
        "token":"mQUYQdffOSAMJYtm8pVpkOsVqXt5hglnuSpO5EMbgJMNEPFGaiDe8OUjvrJ2WcYcBSLgqynu9jaPFvZHMl83ybMvp6aDIDARjTFIBpRWod6p32fL9LIpIStvc6k8Wrs1",
        "endpoint":"https:\/\/cloud.example.com\/login\/v2\/poll"
   },
   "login":"https:\/\/cloud.example.com\/login\/v2\/flow\/guyjGtcKPTKCi4epIRIupIexgJ8wNInMFSfHabACRPZUkmEaWZSM54bFkFuzWksbps7jmTFQjeskLpyJXyhpHlgK8sZBn9HXLXjohIx5iXgJKdOkkZTYCzUWHlsg3YFg"
}

The url in login should be opened in the default browser, this is where the user will follow the login procedure.

So I assume the behavior of that url is what needs to be changed to include the terms of services modal.

[max-nextcloud]

Looks like this is in core/Controller/ClientFlowLoginV2Controller.php
landing will redirect to showAuthPickerPage.
Which renders the loginflowv2/authpicker template.

[max-nextcloud]

My understanding is that normally terms of service are shown after the login. That does not seem easy in this case as after the login the server will already approve the desktop client.

So we would need to hook into that somewhere to delay it until the TOS has been accepted.

[max-nextcloud]

@nickvergessen what's your take on this? Any idea where we could hook into the server code?

[nickvergessen]

nextcloud/registration#293 could be used as inspiration.
Basically server needs to provide an option to "add JS" and then this app here would listen to it,
add some frontend into the page and otherwise block "continuing":
https://github.com/nextcloud/terms_of_service/blob/master/lib/Listener/RegistrationIntegration.php