express-discover

Allows connected Express applications to discover each other without configuration.

Install

Install from NPM

npm install express-discover -S

And import into your project

import registerService from "express-discover";

const registerService = require("express-discover");

Usage

The default exported method sets up an Express app to be used in a middleware network, such that each Express app is discoverable by name. The registerService method should be called on all Express applications that need to be discovered.

const mainapp = express();
registerService(mainapp, "main");

const authapp = express();
registerService(authapp, "auth");

Once all the apps have been registered, they need to be connected. This done very simply by using the middleware. As long as all the middleware have a shared root Express app, they can discover one another, even if they are deeply buried in many other Express apps.

// use just like you normally would
mainapp.use("/auth", authapp);

// now main and auth can find each other!
authapp.discover("main") === mainapp; // true
mainapp.discoverPath("auth") === "/auth"; // true

API

registerService( app, name [, backupPaths ] )

The default exported function that setups an app to be discovered.

• app (Express App, required) - The application to make discoverable. Discovery API functions will be attached this app as well.
• name (String, required) - The name of the application. It is recommended to make this value unique. When discovering apps, the first app with the specified name is returned.
• backupPaths (Object) - An object of service names to string paths. This is used by app.discoverPath() when an app can't be found.

app.discover( name )

Returns the first discoverable app with name.

• name (String, required) - The name of the app you are attempting to discover. This should match what was given to registerService().

app.discoverPath( name [, params ] )

Returns the full URL path to the first discoverable app with name. Since this uses app.path(), it has the side effect of returning application mount path literals. To combat this issue, you can pass an object of params to values, to fill in Express path segments like /:param.

• name (String, required) - The name of the app you are attempting to get the URL for. This should match what was given to registerService().
• params (Object) - An object of URL parameters to fill in.