Build Simple REST API using Go with gin-gorm

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REST (Representational State Transfer) is an architectural method of communication that uses HTTP protocol for data exchange. Application programming interface (API) is a connection between computers or between computer programs. It is a type of software interface, offering a service to other pieces of software. In short, API can make other applications, whether it’s a mobile apps or something else, can communicate with our application.

In this post I want to share how to create a simple REST API in Go using gin and gorm in a simple way.

First, create new go project using go mod command

# Create folder
mkdir go-api
# Change dir into go-api
cd go-api
# Init go project
go mod init go-api

Install gin package

go get -u github.com/gin-gonic/gin

Install gorm package and db driver, db driver can be customized as needed or desired. For supported db driver you can check in here. In this post I will use postgreSQL.

go get -u gorm.io/gorm
go get -u gorm.io/driver/postgres

Since Go let us structure the project according to what we want and also go does not have a standard structure. This is structure I will use for this project or you can define your own.

Create a go file for set db connection in, I will create it in src/config
as db.go.

package database

import (
 "gorm.io/driver/postgres"
 "gorm.io/gorm"
)

func Connect() *gorm.DB {
 dsn := "host=localhost user=root password=root dbname=go-api port=9920 sslmode=disable TimeZone=Asia/Shanghai"
 db, err := gorm.Open(postgres.Open(dsn), &gorm.Config{})
 if err != nil {
  panic(err)
 }

 return db
}

Then create a struct for represent our data from database, in this I will create a simple src/apps/post/model.go

package post

type Post struct {
 ID    int    `json:"id"`
 Title string `json:"title"`
 Body  string `json:"body"`
}

Then create a controller or handler file src/apps/post/handler.go

Create a go file src/cmd/main/main.go, then add code to setup the router.

package main

import (
 "go-api/src/apps/post"
 "go-api/src/config/database"

 "github.com/gin-gonic/gin"
)

func main() {
 // Connect to database
 db := database.Connect()

 // Migrate database
 db.AutoMigrate(&post.Post{})

 // Create post handler
 postHandler := post.NewPostHandler(db)

 // Create router
 router := gin.Default()
 api := router.Group("/api")
 postRoute := api.Group("/post")
 postRoute.GET("", postHandler.GetPosts)
 postRoute.GET("/:id", postHandler.GetPost)
 postRoute.POST("", postHandler.CreatePost)
 postRoute.PUT("/:id", postHandler.UpdatePost)
 postRoute.DELETE("/:id", postHandler.DeletePost)

 // Run server
 router.Run()
}

Test
Run go run src/cmd/main/main.go, once our app is running we can test our API using apps such as postman, insomnia etc. I will use postman for testing our API.

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Thanks for reading my post, please feel free to leave comments for any suggestions or questions. Share this post if you find this post useful. See ya…

Repository
- https://github.com/awgst/go-api

References
- https://www.ibm.com/topics/rest-apis#:~:text=the%20next%20step-,What%20is%20a%20REST%20API%3F,representational%20state%20transfer%20architectural%20style.
- https://gorm.io/
- https://gin-gonic.com/