Edge Server with MongoDB Node.js Driver

This example todo application demonstrates using Atlas Edge Server with a MongoDB Driver. It uses the MongoDB Node.js Driver in an Express server application to connect to Edge Server. It has a React frontend for performing CRUD operations.

React client -> Express server (Node.js Driver) -> Edge Server -> Atlas

This is a MERN stack that connects to the Edge Server instead of Atlas. In this version of the example app, MongoDB wire protocol connections connect directly to Edge Server. You can use email/password authentication with an App Services user or bypass authentication altogether.

For a MERN stack tutorial, refer to How to Use Mern Stack: A Complete Guide.

Atlas Edge Server is currently in Public Preview. To learn more about Edge Server, refer to the product page at Edge Server and the Edge Server documentation.

Quick Start

Create an App Services App based on the edge-server.todo template app. Refer to the documentation for details.
Create a Service for Edge Server
Start Docker
Install and Configure the Edge Server Instance
As part of the Edge Server installation, choose to create a new user. Remember the user's email and password for later. Alternatively, you can skip user creation and disable authentication by running edgectl config --insecure-disable-auth=true.
From the project's root directory, run npm run install-deps.

Add a .env file inside the express-server directory with the details required to run the Express Server.

 # The Edge Server uses this connection string for anonymous authentication
 EDGE_SERVER_URI="mongodb://localhost:27021"

 # This port is for the Express server
 PORT=5055

From the project's root directory, run npm run start.
In the rendered React client, either bypass authentication or use the email and password for the user you created earlier.

When you're done with the template app, make sure to shut everything down, including the Edge Server. From the project's root directory, run npm run stop.

Project npm commands

install-deps: installs the dependencies for the Express server and React client. You must install the Edge Server dependencies separately.
start: starts the Edge Server, Express server, and React client.
stop: shuts down the Edge Server, Express server, and React client.

Create an App Services App

Edge Server connects to Atlas through an App Services App backend. For this example application, you'll create an App Services App based on the edge-server.todo template app.

This template app uses a backend with Atlas Device Sync enabled and configured with:

An pre-defined Item collection in a todo database
Three rules:
- A default rule that allows any user to read, but not write, Items to the collection
- A rule that allows the Edge Server to read and write Items to the collection
- A rule that allows Atlas Device SDK client users to read all Items, but only write their own Items to the collection

NOTE: You must use the edge-server.todo template app. You can sync data with Atlas Device SDK clients if they connect to the Edge Server.

Set up your MongoDB Atlas account

You will need the following to create an App in the CLI:

A MongoDB Atlas account with Project Owner permissions. To learn how to sign up for a free account, refer to Get Started with Atlas.
A cluster deployed in your project. To learn how to deploy an M0 free cluster, refer to Create a Cluster.
A project API key with Project Owner permissions. To learn how to create a key, refer to Create an API Key for a Project.

Create an App with App Services CLI

Install App Services CLI:

npm install -g atlas-app-services-cli

appservices login \
--api-key <your-public-key> \
--private-api-key <your-private-key>

Create an app based on the edge-server.todo template using appservices apps create.

The following creates an app named "EdgeServerApp" that uses the template's pre-configured backend. The command creates a new EdgeServerApp directory in your current path containing the backend files:

appservices app create \
--name EdgeServerApp \
--template edge-server.todo

If the app is created successfully, you should see a JSON blob that includes the generated client_app_id similar to:

{
  "client_app_id": "edgeserverapp-abc123",
  "filepath": "/current_path/EdgeServerApp",
  "url": "https://realm.mongodb.com/groups/1234567890abcdefghijk/apps/1234567890abcdefghijk/dashboard",
  "backend": "/current_path/EdgeServerApp/backend",
  "frontends": "/current_path/EdgeServerApp/frontend",
  "clusters": [
    {
      "name": "mongodb-atlas"
    }
  ]
}

You now have an App Services App with a configured backend and an App Services App ID.

NOTE: The client_app_id is your App Services App ID. You will need it later steps.

While Edge Server is in Private Preview, the frontends directory listed in the blob does not apply to this template. You can only get the Edge Server client from this GitHub repository: https://github.com/mongodb/template-app-edge-server/

Additionally, the "View directions on how to run the template app:" text does not contain information about running the Edge Server template. You can view the Edge Server client README - this document you're currently viewing - for those details.

Set up Edge Server

Before you can run the template app in this repo, you need to have a functional Edge Server.

To set up an Edge Server:

For more information about Atlas Edge Server instance, refer to the Edge Server documentation.

Install Express and React dependencies and start servers

Install and configure the Edge Server. You must install the Edge Server dependencies yourself for details, refer to the Edge Server documentation.
Install the Express server and React client dependencies. From the project root, run:
```
npm run install-deps
```

Add a .env file inside the express-server directory with the details required to run the Express Server.

 # The Edge Server uses this connection string for anonymous authentication
 EDGE_SERVER_URI="mongodb://localhost:27021"

 # This port is for the Express server
 PORT=5055

Start the Edge Server, Express server, and React client server. From the project root, run:
```
npm run start
```
This should open a browser window with the UI where you can either bypass authentication or pass a user's email address and password to the Edge Server. After logging in, you can perform CRUD operations through the Express server that is connected to the Edge Server. You can open Atlas and see your updates reflected there.

If a browser windwo doesn't open automatically, you can open one and navigate to the following URL to view the React app:
```
http://localhost:3000/
```
When you're done, shut down all three servers. From the project root, run:
```
npm run stop
```

Run Multiple Edge Server Instances on a Host

If your device has multiple Edge Server instances, running this project's npm run start script uses the default edgectl profile. If you want to use a different profile, you must run the Edge Server with the appropriate --profile flag, and run the express-server and react-client separately.

See the Edge Server documentation for more details.

Using the React client

Authenticate

Before you can read or write any data from the Edge Server, you must either bypass authentication or log in with a user email address and password.

You can manage users in the App Services UI. If you don't have one yet, you can create a new user that uses email/password authentication. See the App Services authenticate and manage users docs for details.

Add, Update, and Delete Items

The React client is a simple app where you can create, read, update, and delete items. Changes that you make from the React app use the Node.js Driver in the Express server to perform CRUD operations with the MongoDB instance running in the Edge Server. The Edge Server then syncs these changes to Atlas.

You can see the changes that you make in the React app reflected in Atlas. The React client fetches todos from the Edge Server every 5 seconds.

Issues

Please report issues with the template at: https://github.com/mongodb-university/realm-template-apps/issues/new