synapse-invite-checker/README.md

# Synapse Invite Checker Module

This is a Synapse module that checks incoming invites based on whitelist and blacklist rules. The module allows or blocks invites from certain homeservers depending on whether they appear in a dynamically fetched whitelist or blacklist JSON file.

## Features

- **Whitelist and Blacklist**: Allows invites from homeservers in the whitelist, blocks invites from homeservers in the blacklist.
- **Dynamic Fetching**: The whitelist and blacklist are fetched dynamically from a provided URL, and cached for 10 minutes.
- **Fallback on Failure**: If the JSON file cannot be fetched (e.g., network error), the module automatically allows all invites to prevent disruptions.

## Configuration

Add this module to your Synapse's `homeserver.yaml` under the `modules` section. Here’s an example configuration:

```yaml
modules:
  - module: synapse_invite_checker.InviteChecker
    config:
      # URL to fetch the JSON file containing the whitelist and blacklist
      blacklist_whitelist_url: "https://example.com/invite-checker-lists.json"

      # Whether to use the whitelist to allow certain homeservers (default: true)
      use_whitelist: true

      # Whether to use the blacklist to block certain homeservers (default: true)
      use_blacklist: true