Express real world app with Uptrace client

This is a fork which demonstrates how to instrument Express application using Uptrace and OpenTelemetry. To run this app:

# Start MongoDB.
docker run --name realworld-mongo -p 27017:27017 mongo

UPTRACE_DSN="https://<token>@api.uptrace.dev/<project_id>" node app.js

Example Node (Express + Mongoose) codebase containing real world examples (CRUD, auth, advanced patterns, etc) that adheres to the RealWorld API spec.

This repo is functionality complete — PRs and issues welcome!

Getting started

To get the Node server running locally:

• Clone this repo
• npm install to install all required dependencies
• Install MongoDB Community Edition (instructions) and run it by executing mongod
• npm run dev to start the local server

Alternately, to quickly try out this repo in the cloud, you can

Code Overview

Dependencies

• expressjs - The server for handling and routing HTTP requests
• express-jwt - Middleware for validating JWTs for authentication
• jsonwebtoken - For generating JWTs used by authentication
• mongoose - For modeling and mapping MongoDB data to javascript
• mongoose-unique-validator - For handling unique validation errors in Mongoose. Mongoose only handles validation at the document level, so a unique index across a collection will throw an exception at the driver level. The mongoose-unique-validator plugin helps us by formatting the error like a normal mongoose ValidationError.
• passport - For handling user authentication
• slug - For encoding titles into a URL-friendly format

Application Structure

• app.js - The entry point to our application. This file defines our express server and connects it to MongoDB using mongoose. It also requires the routes and models we'll be using in the application.
• config/ - This folder contains configuration for passport as well as a central location for configuration/environment variables.
• routes/ - This folder contains the route definitions for our API.
• models/ - This folder contains the schema definitions for our Mongoose models.

Error Handling

In routes/api/index.js, we define a error-handling middleware for handling Mongoose's ValidationError. This middleware will respond with a 422 status code and format the response to have error messages the clients can understand

Authentication

Requests are authenticated using the Authorization header with a valid JWT. We define two express middlewares in routes/auth.js that can be used to authenticate requests. The required middleware configures the express-jwt middleware using our application's secret and will return a 401 status code if the request cannot be authenticated. The payload of the JWT can then be accessed from req.payload in the endpoint. The optional middleware configures the express-jwt in the same way as required, but will not return a 401 status code if the request cannot be authenticated.