🚀 Building a REST API in Go: A Step-by-Step Guide

Table Of Contents

• Introduction
• Setting Up the Project
• Creating the Todo Model
• Implementing the CRUD Operations
  • Create Todo
  • Get Todos
  • Update Todo
  • Delete Todo
• Testing the API
• Conclusion

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Introduction

Building a REST API can seem daunting, but with Go, it’s straightforward. In this guide, we’ll create a simple Todo REST API that allows users to manage their tasks efficiently.

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Setting Up the Project

To start, make sure you have Go installed on your machine. Create a new directory for your project and initialize a new Go module:

mkdir todorest
cd todorest
go mod init todorest

Install the required packages:

go get github.com/gin-gonic/gin

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Creating the Todo Model

First, we need to define our Todo model. Create a new file called models.go:

package models

type Todo struct {
    ID     int    `json:"id"`
    Title  string `json:"title"`
    Status string `json:"status"`
}

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Implementing the CRUD Operations

Create Todo

To create a new todo item, add the following handler in your main file:

func CreateTodo(c *gin.Context) {
    var todo models.Todo
    if err := c.ShouldBindJSON(&todo); err != nil {
        c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid request"})
        return
    }

    result, err := config.DB.Exec("INSERT INTO todos (title, status) VALUES (?, ?)", todo.Title, todo.Status)
    if err != nil {
        c.JSON(http.StatusInternalServerError, gin.H{"error": "Unable to create todo"})
        return
    }

    id, _ := result.LastInsertId()
    todo.ID = int(id)
    c.JSON(http.StatusCreated, todo)
}

Get Todos

To fetch all todo items, implement the following handler:

func GetTodos(c *gin.Context) {
    rows, err := config.DB.Query("SELECT id, title, status FROM todos")
    if err != nil {
        c.JSON(http.StatusInternalServerError, gin.H{"error": "Unable to fetch todos"})
        return
    }
    defer rows.Close()

    var todos []models.Todo
    for rows.Next() {
        var todo models.Todo
        if err := rows.Scan(&todo.ID, &todo.Title, &todo.Status); err != nil {
            c.JSON(http.StatusInternalServerError, gin.H{"error": "Error scanning todo"})
            return
        }
        todos = append(todos, todo)
    }

    c.JSON(http.StatusOK, todos)
}

Update Todo

To update an existing todo item, you can use:

func UpdateTodo(c *gin.Context) {
    id := c.Param("id")

    var todo models.Todo
    if err := c.ShouldBindJSON(&todo); err != nil {
        c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid request"})
        return
    }

    _, err := config.DB.Exec("UPDATE todos SET title = ?, status = ? WHERE id = ?", todo.Title, todo.Status, id)
    if err != nil {
        c.JSON(http.StatusInternalServerError, gin.H{"error": "Unable to update todo"})
        return
    }

    c.JSON(http.StatusOK, todo)
}

Delete Todo

To delete a todo item, implement the following function:

func DeleteTodo(c *gin.Context) {
    id := c.Param("id")

    _, err := config.DB.Exec("DELETE FROM todos WHERE id = ?", id)
    if err != nil {
        c.JSON(http.StatusInternalServerError, gin.H{"error": "Unable to delete todo"})
        return
    }

    c.JSON(http.StatusOK, gin.H{"message": "Todo deleted"})
}

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Testing the API

To test your API, you can use tools like Postman or CURL. Make sure your server is running, and send requests to the appropriate endpoints.

View the Todo REST API on GitHub

Conclusion

You have successfully built a Todo REST API in Go! You can extend its functionality by adding more features like authentication, filtering, and pagination.

For further reading, check out the official Go documentation for more details on the Go language and its capabilities.

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