Auth-API

Creating an Authentication API with Golang

Installation (ref: Thanks to ==> Dijkhuizen)

You need to install Go on your PC or MacOS and set your Go workspace first

• The first need Go installed (Latest {stable} version is awesome)

Getting Started

• To get started, Create a new project then, Create a new file called main.go and enter the following starter code:

package main
import (
  "fmt"
  "net/http"
  "github.com/gin-gonic/gin"
)

POST and GET methods

• To be able to handle GET and POST requests, we create a GetMethod and PostMethod:

func PostMethod(c *gin.Context) {
  fmt.Println("\napi.go 'PostMethod' called")
  message := "PostMethod called"
  c.JSON(http.StatusOK, message)
}
func GetMethod(c *gin.Context) {
  fmt.Println("\napi.go 'GetMethod' called")
  message := "GetMethod called"
  c.JSON(http.StatusOK, message)
}

Main function

• We need to create a Gin router for handling all the requests:

func main() {
  router := gin.Default()
}

• Following this up, we add in the GetMethod and PostMethod:

func main() {
  router := gin.Default()
router.POST("/", PostMethod)
  router.GET("/", GetMethod)
}

• we add the port for the server to listen to and run the server: Just top the below code in Gin

func main() {
  router := gin.Default()
router.POST("/", PostMethod)
  router.GET("/", GetMethod)
listenPort := "4000"
router.Run(":"+listenPort)
}

• Now, run this code to test if your server is working.

Authentication

• Now that you’ve set up our basic web server, we can start adding in the elements for our authentication API.

• let's start with func main():

func main() {
  router := gin.Default()
subRouterAuthenticated := router.Group("/api/v1/PersonId", gin.BasicAuth(gin.Accounts{
    "admin": "adminpass",
  }))
listenPort := "1357"
router.Run(":"+listenPort)
}

• passing the query string parameters

func main() {
  router := gin.Default()
subRouterAuthenticated := router.Group("/api/v1/PersonId", gin.BasicAuth(gin.Accounts{
    "admin": "adminpass",
  }))
subRouterAuthenticated.GET("/:IdValue", GetMethod)
listenPort := "1357"
  router.Run(":"+listenPort)
}

Adjusting our GetMethod()

• It fetches and prints the Person IdValue from the query string parameter passed in the API URL:

func GetMethod(c *gin.Context) {
  fmt.Println("\n'GetMethod' called")
  IdValue := c.Params.ByName("IdValue")
  message := "GetMethod Called With Param: " + IdValue
  c.JSON(http.StatusOK, message)
ReqPayload := make([]byte, 1024)
  ReqPayload, err := c.GetRawData()
  if err != nil {
        fmt.Println(err)
        return
  }
  fmt.Println("Request Payload Data: ", string(ReqPayload))
}

For efficient practice check my main.go file

Testing With ngrok

• First, run your Go application

go run main.go

1. Download ngrok
2. Extract the ngrok executable in a folder on your server.
3. Start ngrok on port 1357 (which is the port you selected in your code).

• p.s you can configure your port

./ngrok http 1357

• The result:

ngrok by @emmyc                                               (Ctrl+C to quit)
Session Status                online                                                         
Session Expires               7 hours, 12 minutes                                            
Version                       2.3.35                                                         
Region                        Netherlands (nl)                                             
Web Interface                 http://127.0.0.1:4040                                          
Forwarding                    http://ca6d2c4cee3e.ngrok.io -> http://localhost:4000          
Forwarding                    https://ca6d2c4cee3e.ngrok.io -> http://localhost:4000

• This will generate a random dynamic URL where you can test your API and log in with your login details to test if it works.

• After you log in, it will show:

GetMethod Called With Param: Id456

• Great It works!