Go REST API with MongoDB

A simple REST API built with Go (Golang) and MongoDB for performing CRUD operations on user data.

Prerequisites

• Go 1.16 or higher
• Docker and Docker Compose
• Postman (for testing the API)

Project Structure

testapi/
├── docker-compose.yml
├── .env
├── main.go
├── models/
│   └── user.go
└── handlers/
    └── user_handler.go

Setup and Installation

1. Clone the repository:

git clone <your-repo-url>
cd testapi

2. Start MongoDB using Docker:

docker-compose up -d

3. Run the application:

go run main.go

The server will start on http://localhost:8080

API Endpoints

1. Create User

• Method: POST
• URL: http://localhost:8080/users
• Headers:
  • Content-Type: application/json
• Request Body:

{
    "name": "John Doe",
    "email": "[email protected]",
    "age": 30
}

• Success Response:
  • Status: 200 OK
  • Returns the created user ID

2. Get All Users

• Method: GET
• URL: http://localhost:8080/users
• Success Response:
  • Status: 200 OK
  • Returns array of users

3. Get Single User

• Method: GET
• URL: http://localhost:8080/users/{id}
• URL Parameters: id=[string] (MongoDB ObjectID)
• Success Response:
  • Status: 200 OK
  • Returns user object

4. Update User

• Method: PUT
• URL: http://localhost:8080/users/{id}
• URL Parameters: id=[string] (MongoDB ObjectID)
• Headers:
  • Content-Type: application/json
• Request Body:

{
    "name": "John Updated",
    "email": "[email protected]",
    "age": 31
}

• Success Response:
  • Status: 200 OK
  • Returns update result

5. Delete User

• Method: DELETE
• URL: http://localhost:8080/users/{id}
• URL Parameters: id=[string] (MongoDB ObjectID)
• Success Response:
  • Status: 200 OK
  • Returns delete result

Testing with Postman

1. Open Postman
2. Create a new Collection called "User API"
3. Add new requests for each endpoint:

Create User Request

1. Create new POST request to http://localhost:8080/users
2. Go to Headers tab:
   • Add Content-Type: application/json
3. Go to Body tab:
   • Select "raw"
   • Choose "JSON" from dropdown
   • Add user JSON object

Get Users Request

1. Create new GET request to http://localhost:8080/users
2. No additional headers or body needed

Get Single User Request

1. Create new GET request to http://localhost:8080/users/{id}
2. Replace {id} with actual user ID from create response

Update User Request

1. Create new PUT request to http://localhost:8080/users/{id}
2. Add same headers as Create User
3. Add updated user JSON in body

Delete User Request

1. Create new DELETE request to http://localhost:8080/users/{id}
2. Replace {id} with actual user ID

Environment Variables

The application uses following environment variables (stored in .env):

• MONGODB_URI: MongoDB connection string
• DATABASE_NAME: Name of the database

Error Handling

The API returns appropriate HTTP status codes:

• 200: Success
• 404: Resource not found
• 500: Server error

MongoDB Connection

MongoDB runs in Docker container with following credentials:

• Host: localhost
• Port: 27017
• Username: admin
• Password: password

Stopping the Application

1. Stop the Go server with Ctrl+C
2. Stop MongoDB container:

docker-compose down

Data Model

User model structure:

type User struct {
    ID    primitive.ObjectID `json:"id,omitempty" bson:"_id,omitempty"`
    Name  string            `json:"name,omitempty" bson:"name,omitempty"`
    Email string            `json:"email,omitempty" bson:"email,omitempty"`
    Age   int               `json:"age,omitempty" bson:"age,omitempty"`
}