Accept username from app link e.g. via URL param

[djschilling]

I want an easy way for users to login to element web for a given username.

Background

We use matrix as chatplatform for our customers. We have a PaaS called ChurchTools.
Every church have their own ChurchTools Installation.

We built the login to matrix like this:

Username: @ct_6c659f63b-9fd7-4sd1-91ae-635fa0751ea9:chat.church.tools (The users guid in churchtools)
Passwort: the users ChurchTools password

In our app we built a matrix client, it handles the login automatically.

Now we want our users also to have the option to use element-web in the browser.

The username is quite long and not really important for the user to know so we don't want him to type it in the element web login form.

This is were this issue is needed.

proposed idea

Our idea was to have the option to call the element-web login page with a prefilled username so we can link from ChurchTools directly to element-web and prefill its username so he only has to fill in his ChurchTools password.

[djschilling]

i implemented an url parameter which prefills the username here: matrix-org/matrix-react-sdk#5674