synapse-invite-checker/README.md

# Synapse Invite Checker Module

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

## Features

- **allowlist and blocklist**: Allows invites from homeservers in the allowlist, blocks invites from homeservers in the blocklist.
- **Dynamic Fetching**: The allowlist and blocklist are fetched dynamically from a provided URL, and cached.
- **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 allowlist and blocklist
      blocklist_allowlist_url: "https://example.com/invite-checker-lists.json"
      # Whether to use the allowlist to allow certain homeservers (default: true)
      use_allowlist: true
      # Whether to use the blocklist to block certain homeservers (default: true)
      use_blocklist: true