Fred

Posted on Nov 8 • Edited on Nov 9

Building a Simple RESTful API in Go for Managing Blog Posts

Introduction

We know the best way to learn is to build stuff while learning, so I got into building a RESTful API to manage blog posts. It’s a simple project that lets you create, read, update, and delete posts—basically, the classic CRUD operations. I chose Go because I'm familiar with it,😂😂😎😂! It's a great language for this kind of project, and it makes the whole process smoother since I already know my way around it. Plus, Go’s performance is top-notch, which makes it perfect for handling API requests quickly.

1. Overview

In this tutorial, we’ll walk through the entire process of creating a simple RESTful API in Go to manage blog posts. The API will allow us to perform the basic CRUD operations: Create, Read, Update, and Delete posts. We'll structure the application with a few simple files to keep things clear.

2. Our Entry Point

FILE: main.go

package main

import (
    "log"
    "net/http"

    "your_project/route" // import your route package
)

func main() {
    r := route.NewRouter() // initialize the router
    log.Fatal(http.ListenAndServe(":8080", r)) // start the server
}

In this file, we set up the HTTP server and the routes using the mux router. The server listens on port 8080, and we define all the routes inside the route.NewRouter() function.

3. Post Model

FILE: model.go

package model

type Post struct {
    Title   string
    Content string
    Tags    []string
    Author   string
}

This Post struct is our model, which represents a blog post. It contains fields for Title, Content, Tags, and Author. Each post will be stored in memory with these fields.

4. Setting Up Routes for CRUD Operations

FILE: route.go

package route

import (
    "github.com/gorilla/mux"

    "your_project/handler"
    "your_project/middleware"
)

func NewRouter() *mux.Router {
    r := mux.NewRouter()
// create a post
    r.HandleFunc("/create", handler.CreatePost).Methods("POST")
// list the titles of all posts
    r.HandleFunc("/list", handler.ListPosts).Methods("GET")
// get a post by the post title
    r.HandleFunc("/post", handler.GetPostByTitle).Methods("GET")
// edit a post
    r.HandleFunc("/edit", handler.UpdatePost).Methods("PUT")
// delete a blog post
    r.HandleFunc("/delete", middleware.RequireAuth(handler.DeletePost)).Methods("DELETE")
    return r
}

Here, we define all the routes for the CRUD operations:

Create Post: POST /create
List All Posts: GET /posts
Get Post by Title: GET /blogs
Update Post: PUT /edit
Delete Post: DELETE /delete

5. Implementing the Handlers

FILE: handler.go

package handler

import (
    "encoding/json"
    "fmt"
    "net/http"

    "your_project/model"
)
// a in-built memory database to store and retrieve our posts.
var allPosts = make(map[string]model.Post)

Create Post(POST)

func CreatePost(w http.ResponseWriter, r *http.Request) {
    var post model.Post
    // read content from request body into a new decoder
    decoder := json.NewDecoder(r.Body)
    // decode content into our Post struct
    err := decoder.Decode(&post)
    if err != nil {
        http.Error(w, "Failed to decode request body", http.StatusInternalServerError)
        return
    }
    // check for unique post title
    _, ok := allPosts[post.Title]
    if ok {
        http.Error(w, "Post title already exists", http.StatusBadRequest)
        return
    }

    // append post to our memory
    allPosts[post.Title] = post

    // prints out structs with field names
    fmt.Fprintf(w, "%+v", post)
}

Get Post(GET)

func ListPosts(w http.ResponseWriter, r *http.Request) {
    titles := []string{}

    for _, post := range allPosts {
        titles = append(titles, post.Title)
    }

    if len(titles) == 0 {
        http.Error(w, "no posts found", http.StatusNotFound)
    }

    json.NewEncoder(w).Encode(titles)
    // uncomment to print out structs with field names
    // fmt.Fprintf(w,"%+v",titles)
}

Get Post by Title(GET)

func GetPostByTitle(w http.ResponseWriter, r *http.Request) {
    // retrieve title of post
    title := r.URL.Query().Get("title")
    if title == "" {
        http.Error(w, "Title is required", http.StatusBadRequest)
        return
    }

    // check title is present
    post, ok := allPosts[title]
    if !ok {
        http.Error(w, "Post not found", http.StatusNotFound)
        return

    }

    // encode the contents
    if err := json.NewEncoder(w).Encode(post); err != nil {
        http.Error(w, "Post not found", http.StatusInternalServerError)
        return
    }
}

Update Post(PUT)

func UpdatePost(w http.ResponseWriter, r *http.Request) {
    // get title
    // check title is provided
    title := r.URL.Query().Get("title")
    if title == "" {
        http.Error(w, "Title is required", http.StatusBadRequest)
        return
    }

    // check if such post exists
    post, ok := allPosts[title]
    if !ok {
        http.Error(w, "BlogPost not found", http.StatusNotFound)
        return
    }
var updatedPost model.Post

    // read request body
    if err := json.NewDecoder(r.Body).Decode(&updatedPost); err != nil {
        http.Error(w, "Failed to decode request body", http.StatusBadRequest)
        return
    }

    // update post
    allPosts[title] = updatedPost
    post = updatedPost

    // return ok status
    w.WriteHeader(http.StatusOK)

    // return updated content
    json.NewEncoder(w).Encode(post)


}

Delete Post(Delete)

func DeletePost(w http.ResponseWriter, r *http.Request) {
    title := r.URL.Query().Get("title")

    // retrieve post
    _, ok := allPosts[title]
    if !ok {
        http.Error(w, "No post with such title", http.StatusNotFound)
    }
       // deletes the post from the map.
    delete(allPosts, title)

    w.WriteHeader(http.StatusOK)
}

These handler functions handle the logic for each CRUD operation. They read the request body (for POST and PUT requests), interact with the in-memory database (allPosts), and send responses accordingly.

6. Middleware (Authentication)

FILE: auth.go

package middleware

import "net/http"

func RequireAuth(f http.HandlerFunc) http.HandlerFunc {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        // check if user is authenticated
        token := r.Header.Get("Authorization")
        if token != "Bearer Secret" {
            http.Error(w,"Unathorized", http.StatusUnauthorized)
            return
        }
        f.ServeHTTP(w,r)
    })
}

This middleware function checks for a valid Authorization header. If the token isn’t Bearer Secret, it returns an unauthorized response.

7.Run the Aplication

Run the following commands to initialize and tidy up dependencies:
run to install.

cd your_project
go mod init your_project
go mod tidy

8. Testing our API

Once the API is up and running, you can test the endpoints using curl commands.

Run the server:

go run main.go

Using `curl`

Then, in another terminal window, use curl to test:

Create Post:

curl -X POST -H "Content-Type: application/json" -d '{"title":"My First Post", "content":"This is the content.", "author":"John Doe"}' http://localhost:8080/create

Get Post by Post Title:

curl -X GET 'http://localhost:8080/post?title=My%20First%20Post'

Get All Posts Titles:

curl http://localhost:8080/list

Update Post

curl -X PUT -H "Content-Type: application/json" -d '{"Title":"My First Post", "Content":"Updated content.", "Author":"John Doe"}' 'http://localhost:8080/edit?title=My%20Blog%20Post'

Delete Post

curl -X DELETE -H "Authorization: Bearer Secret" 'http://localhost:8080/delete?title=My%20First%20Post'

Using `Thunder Client`

Thunder Client is a lightweight and powerful API testing tool, typically used within Visual Studio Code (VS Code). It offers a user-friendly interface to make API requests.

Check out how to use Thunder Client to make API requests :

Conclusion

And there you have it—your very own RESTful API for managing blog posts, built with the power of Go! 🚀. From creating posts to updating, deleting, and viewing them.
But wait—Want to add user authentication, store data in a database, or make your API even more scalable? Go for it! 🔥