potential new user registers on a bot-provided side
bot sends a message to predefined room with a registration notification.
users in that room now can approve or decline the registration.
When approved
- the bot creates credentials
- sends them to the user
- stores them encrypted in own database
- provides that credentials to matrix-synapse-rest-auth which has to be configured to query login.php

2nd step: Implement the other apis to integrade mxisd

This bot takes care for user accounts. So it stores the credentials itself and provides ways to access them via matrix-synapse-rest-auth or mxisd.

How to install

Copy config.sample.php to config.php and configure the bot as you can find there
Configure your webserver to publish the folder public. The folder internal contains files that can be accessed by mxisd or matrix-synapse-rest-auth or else via a reverse proxy
To integrate with matrix-synapse-rest-auth:
- /_matrix-internal/identity/v1/check_credentials should map to internal/login.php
To integrate with mxisd: Have a look at the docs and apply as follows:

Key	file which handles that	Description
rest.endpoints.auth	internal/login.php	Validate credentials and get user profile
rest.endpoints.directory	internal/directory_search.php	Search for users by arbitrary input
rest.endpoints.identity.single	internal/identity_single.php	Endpoint to query a single 3PID
rest.endpoints.identity.bulk	internal/identity_bulk.php	Endpoint to query a list of 3PID

Implement usage of additional features:

Use the ChangePasswortInterceptor:

You need a reverse proxy which maps /_matrix/client/r0/account/password to internal/intercept_change_password.php. Here is an example for nginx:

        location /_matrix/client/r0/account/password {
                proxy_pass http://localhost/mxbot/internal/intercept_change_password.php;
                proxy_set_header X-Forwarded-For $remote_addr;
        }