🪐🛰️ NASA Mars Rovers GraphQL Server

A GraphQL API server built with TypeScript and Node.js, designed to provide data about NASA's Mars Rovers. This project leverages GraphQL for efficient data querying and follows modern software design practices for scalability and maintainability.

Explore the wonders of Mars with this GraphQL server! 🔭

🌐 LIVE SERVER: https://nasa-marsrovers-graphql-server.onrender.com/

📑 Table of Contents

• 🧑‍💻 Features
• 🎨 Technology Stack
• 🗂️ Project Structure
• 📖 How to Use This Repo
• 🔍 Example Queries
• 🔮 Future Improvements
• 📜 License

🧑‍💻 Features

• Fetch a list of Mars Rover photos and Filter photos by Martian Sol or Earth Date.
• Retrieve detailed information about a specific photo.
• Increment the view count for a photo.
• Query data efficiently using GraphQL.

🎨 Technology Stack

Key Technologies

Technology	Purpose
GraphQL	Provides a flexible and efficient API for querying data.
TypeScript	Ensures type safety and better developer experience.
Node.js	Powers the server runtime.
Apollo Server	Simplifies the implementation of the GraphQL API.
GraphQL Code Generator	Automatically generates TypeScript types and resolvers.
RESTDataSource	Used to interact with NASA's REST API.

Design Practices

• API First / Schema First: The GraphQL schema is defined first, serving as the contract for the API and ensuring consistency between the client and server. This also enables parallel development between client and server.
• Type-Safe Development: TypeScript is used throughout the project to reduce runtime errors and improve code quality.
• Separation of Concerns: The project is modular, with clear separation between schema definitions, resolvers, and data sources.
• Code Generation: GraphQL Code Generator is used to generate types and resolvers, ensuring consistency between the schema and implementation.
• Environment Variables: Sensitive data like API keys are managed using .env files.

🗂️ Project Structure

The project is organized as follows:

src/
├── api-contract/         # GraphQL schema and example queries
├── context.ts            # Context definition for Apollo Server
├── datasources/          # Data sources for interacting with external APIs
├── models/               # TypeScript models for domain entities
├── resolvers/            # GraphQL resolvers implementation
├── schema.ts             # Schema loading and executable schema creation
├── types.ts              # Auto-generated TypeScript types for GraphQL
└── index.ts              # Entry point for the server

Key Files

• src/schema.ts: Loads the GraphQL schema and creates an executable schema.
• src/resolvers/resolvers.ts: Implements the logic for GraphQL queries and mutations.
• src/datasources/nasa-mars-api.ts: Handles communication with NASA's Mars Rover API.
• src/types.ts: Contains TypeScript types generated from the GraphQL schema.

📖 How to Use This Repo

Follow these steps to set up and run the server:

⚙️ Setup

1. Navigate to the server folder:

   cd server

2. Install dependencies:

   npm install

🚀 Running the Server

Development Mode:

Run the server in development mode with live reloading:

npm run dev

Production Mode:

Start the server in production mode:

npm start

This will launch the GraphQL API server, ready to handle requests. 🚀

🔍 Example Queries

Here are some example queries you can use to interact with the API:

Fetch All Mars Photos

query GetMarsPhotos {
  marsPhotos {
    id
    sol
    camera {
      name
      full_name
    }
    img_src
    earth_date
    number_of_views
    rover {
      name
      status
    }
  }
}

Fetch Mars Photos Filtered by Sol or Earth Date

query GetFilteredMarsPhotos($sol: String, $earth_date: String) {
  marsPhotos(sol: $sol, earth_date: $earth_date) {
    id
    sol
    img_src
    earth_date
    rover {
      name
      status
    }
  }
}

Example Variables

{
  "sol": "1000",
  "earth_date": "2023-09-01"
}

Fetch a Specific Mars Photo by ID and Sol

query GetMarsPhoto($id: ID!, $sol: String) {
  marsPhoto(id: $id, sol: $sol) {
    id
    sol
    img_src
    earth_date
    camera {
      name
      full_name
    }
    rover {
      name
      landing_date
      launch_date
    }
  }
}

Example Variables

{
  "id": "m_1",
  "sol": "1000"
}

This query allows you to fetch a specific Mars photo by its ID and optionally filter it by the Martian sol.

Increment the View Count of a Mars Photo

mutation IncrementMarsPhotoViews($id: ID!) {
  incrementMarsPhotoViews(id: $id) {
    code
    success
    message
    marsPhoto {
      id
      number_of_views
    }
  }
}

This query allows you to filter Mars photos by either the Martian sol or the Earth date. You can provide one or both filters as needed.

Examples Sandbox UI GraphQL Server

🔮 Future Improvements

• Expand the API to include data from other NASA missions.
• Use a dedicated database (e.g., MongoDB) to store application-specific data.
• Add more filtering and sorting options for photos.
• Implement user authentication for personalized features.

📜 License

This project is licensed under the MIT License. See the LICENSE file for details.