A quick Golang code sample for using ApproveAPI to send a magic login link.

magic_link_login.go

import (
    "crypto/rand"
    "encoding/base64"
    "github.com/approveapi/approveapi-go"
    "github.com/go-redis/redis"
    "time"
)

func GenerateRandomToken(n int) (string, error) {
    b := make([]byte, n)
    _, err := rand.Read(b)
    if err != nil {
        return nil, err
    }
    base64.URLEncoding.EncodeToString(b), err
}

func CreateAndSendMagicLink(emailAddress string) err {
    token, err := GenerateRandomToken(32)
    if err != nil {
        return err
    }
    
    expiresIn := time.Hour
    
    // Use a global redis instance or initialize one here
    err = redis.Set(token, emailAddress, expiresIn).Err()
    if err != nil {
        return err
    }
    
    magicLink := fmt.Sprintf(
        "https://bookface.com/login?code=%v", token
    )
    
    err = EmailMagicLink(magicLink, emailAddress)
} 

func EmailMagicLink(magicLink string, emailAddress string) error {
    // Get your API key at https://dashboard.approveapi.com
    client := approveapi.CreateClient("sk_test_yourapikeyhere")

    prompt := approveapi.CreatePromptRequest {
        User: emailAddress,
        Body: "Click the link below to sign into Bookface.com",
        ApproveText: "Login",
        ApproveRedirectUrl: magicLink,    
    }

    _, _, err := client.ApproveApi.CreatePrompt(prompt)
    return err   
}

// Invoke this when the user hits
// the login URL https://bookface.com/login?code=<token>
func AuthenticateToken(token string) {
    emailAddress, err := redis.Get(token)
    if err != nil {
        return err
    }

    // Done! The user with username emailAddress is now authenticated!
    LoginUser(emailAddress)
}