Matrix Application Service Bridging Infrastructure

This library sits on top of the core application service library and provides an API for setting up bridges quickly. Check out the HOW-TO for a step-by-step tutorial on setting up a new bridge.

matrix-appservice-bridge requires Node JS 14.x or greater.

API

A hosted reference can be found on GitHub Pages. Alternatively, build the docs using yarn gendoc. Each component's class constructor is exposed on require("matrix-appservice-bridge") so check each class for more information on how to use each component.

Architecture

 __________________________
|                          |
|   Your bridge e.g. IRC   |
|__________________________|
 __|___________________|___
|                          |
| matrix-appservice-bridge |
|__________________________|
 __|___________________|___
|                          |
|    matrix-appservice     |
|__________________________|

The bridge relies on matrix-appservice and matrix-js-sdk for their AS API and CS API implementations respectively. The bridge manages state for virtual users and provides many useful helper functions bridges may desire.

Components

The bridge is formed around "components". You can pick and choose which components you use, though some components depend upon other components. All components operate on data models defined in the bridge. You can directly construct components: the bridge exposes the class constructor.

BridgeStore

Provides basic document store (key-value) CRUD operations.

UserBridgeStore

Provides storage for matrix and remote users. Provides CRUD operations and mapping between different types of users.

RoomBridgeStore

Provides storage for matrix and remote rooms. Provides CRUD operations and mapping between different types of rooms.

EventBridgeStore

Provides storage for matrix and remote event ids.

ClientFactory

Provides a method to obtain a JS SDK MatrixClient in the context of a particular user_id and/or Request. This is used to send messages as other users.

Request / RequestFactory

An abstraction provided to identify a single request through the bridge. Can be used for request-context logging (each request has a unique ID) and metrics (each request can succeed or fail and has timers for how long they take to go through the bridge).

Intent

Provides a way to perform Matrix actions by intent rather than by raw API calls. This can be thought of as an extension to the client-server JS SDK. For example, intent.invite(roomId, invitee) would make sure that you are actually joined to the room roomId first (and will automatically join it if you aren't) before trying to send the invite.

Performing actions by intent makes creating bridges a lot easier. For example, if your bridge has no concept of inviting or joining rooms, then you don't need to care about it either in the bridge. Simply calling intent.sendMessage(roomId, text) would make sure that you are joined to the room first before sending the message.

ConfigValidator

Provides a way to validate a YAML file when provided with a schema file. Useful for setting your bridge-specific configuration information.

Cli

Processes command line arguments and runs the Bridge.

AppServiceBot

A wrapper around the JS SDK MatrixClient designed for use by the application service itself. Contains helper methods to get all rooms the AS is in, how many virtual / real users are in each, etc.

Bridge

The component which orchestrates other components: a "glue" component. Provides a way to start the bridge. This is the component most examples use. Has dependencies on most of the components listed above.

Logging

This component exposes access to the bridges log reporter. To use, you should install the optional packages winston@3, winston-daily-rotate-file@2 and chalk@2 to get nice formatted log lines, otherwise it will default to the JS console. To use the component, use Logging.configure(configObject) to setup the logger, which takes the following options:

{
    // A level to set the console reporter to.
    console: "error|warn|info|debug|off",

    // Format to append to log files.
    fileDatePattern: "YYYY-MM-DD",

    // Format of the timestamp in log files.
    timestampFormat: "MMM-D HH:mm:ss.SSS",

    // Log files to emit to, keyed of the minimum level they report.
    // You can leave this out, or set it to false to disable files.
    files: {
        // File paths can be relative or absolute, the date is appended onto the end.
        "abc.log" => "error|warn|info|debug|off",
    },

    // The maximum number of files per level before old files get cleaned
    // up. Use 0 to disable.
    maxFiles: 5,
}

You MUST configure the logger before anything will be emitted to the console.

You can then use const log = Logging.Get(ModuleName) to start logging to the reporter, using the log.error, log.warn, log.info or log.debug functions. Arguments to these functions will automatically be seralized if they aren't strings.

NOTE: opts.controller.onLog will override this, but if not set then the logging transport is used.

RoomLinkValidator

This component validates if a room can be linked to a remote channel based on whether it conflicts with any rules given in a rule file. The filename is given in opts.roomLinkValidation.ruleFile for Bridge, though you may also set the rules as an object instead by setting opts.roomLinkValidation.rules. The format for the file (in YAML) or the object is as follows:

{
    // This rule checks the memberlist of a room to determine if it will let
    // the bridge create a link to the room. This is useful for avoiding conflicts
    // with other bridges.
    "userIds": {
        // Anyone in this set will be ALWAYS exempt from the conflicts rule.
        // Here anyone who's localpart starts with nice is exempt.
        "exempt": ["@nice+.:example.com"]
        // This is a regex that will exclude anyone who has "guy" at the end of their localpart.
        // evilbloke is also exempt.
        "conflict": ["@+.guy:example.com", "@evilbloke:example.com"]
    }
}

If you set opts.roomLinkValidation.triggerEndpoint to true, then you may use /_bridge/roomLinkValidator/reload to reload the config from file. This endpoint optionally takes the filename parameter if you want to reload the config from another location.

RoomUpgradeHandler

This component automatically handles Room Upgrades by changing all associated room entries to use the new room id as well as leaving and joining ghosts. It can also be hooked into so you can manually adjust entries, or do an action once the upgrade is over.

This component is disabled by default but can enabled by simply defining roomUpgradeOpts in the options given to the bridge (simply {} (empty object)). By default, users will be copied on upgrade. Upgrade events will also be consumed by the bridge, and will not be emitted by onEvent. For more information, see the docs.

Data Models

• MatrixRoom - A representation of a matrix room.
• RemoteRoom - A representation of a third-party room.
• MatrixUser - A representation of a matrix user.
• RemoteUser - A representation of a third-party user.

Signaling Bridge Errors

Warning: This feature is experimental and not part of the matrix specification yet. MSC2162 is currently ongoing which means that changes will likely happen to the format of the errors. Do not use this in production bridges.

This section applies when you are using Bridge and want to notify your users about problems while processing their events.

One thing the bridge requires you to do is fulfilling or rejecting the request promise which is handed to you as argument of the controller.onEvent callback. When rejecting the promise, the Error you reject with will indicate to the bridge library how to behave:

• On an EventNotHandledError (and all its subtypes) the bridge will declare the event as permanently failed. It will mark it as such by sending a de.nasnotfound.bridge_error room event, which will make clients show an error message to their users.
• On all other Error types no message is sent to the clients. The bridge still uses the information that the event was handled for queuing purposes.