Go

Getting started guide for the Go SDK.

Introduction

The easiest way to set up licensing in your Go application is by using our Go SDK. It’s available on the link below:

• https://github.com/Cryptolens/cryptolens-golang/tree/go_mod

In addition to the SDK, we provide examples in the following repo:

• https://github.com/Cryptolens/cryptolens-golang-examples

Before reviewing the examples, we recommend going through the Getting Started tutorial.

Examples

In the examples below, you would need to replace the token, publicKey, product id and the license key. How they are found is described in the Getting Started tutorial.

Normal activation

package main

import (
	"fmt"
	"github.com/Cryptolens/cryptolens-golang/cryptolens"
	"time"
)

func main() {
	token := "WyI0NjUiLCJBWTBGTlQwZm9WV0FyVnZzMEV1Mm9LOHJmRDZ1SjF0Vk52WTU0VzB2Il0="
	publicKey := "<RSAKeyValue><Modulus>khbyu3/vAEBHi339fTuo2nUaQgSTBj0jvpt5xnLTTF35FLkGI+5Z3wiKfnvQiCLf+5s4r8JB/Uic/i6/iNjPMILlFeE0N6XZ+2pkgwRkfMOcx6eoewypTPUoPpzuAINJxJRpHym3V6ZJZ1UfYvzRcQBD/lBeAYrvhpCwukQMkGushKsOS6U+d+2C9ZNeP+U+uwuv/xu8YBCBAgGb8YdNojcGzM4SbCtwvJ0fuOfmCWZvUoiumfE4x7rAhp1pa9OEbUe0a5HL+1v7+JLBgkNZ7Z2biiHaM6za7GjHCXU8rojatEQER+MpgDuQV3ZPx8RKRdiJgPnz9ApBHFYDHLDzDw==</Modulus><Exponent>AQAB</Exponent></RSAKeyValue>"

	licenseKey, err := cryptolens.KeyActivate(token, cryptolens.KeyActivateArguments{
		ProductId:   3646,
		Key:         "MPDWY-PQAOW-FKSCH-SGAAU",
		MachineCode: "289jf2afs3",
	})
	if err != nil || !licenseKey.HasValidSignature(publicKey) {
		fmt.Println("License key activation failed!")
		return
	}

	fmt.Printf("License key for product with id: %d\n", licenseKey.ProductId)

	if time.Now().After(licenseKey.Expires) {
		fmt.Println("License key has expired")
		return
	}

	if licenseKey.F1 {
		fmt.Println("Welcome! Pro version enabled!")
	} else {
		fmt.Println("Welcome!")
	}
}

Offline activation

package main

import (
	"errors"
	"fmt"
	"github.com/Cryptolens/cryptolens-golang/cryptolens"
	"io/ioutil"
	"time"
)

func ActivateAndSaveLicenseKey() (string, error) {
	token := "WyI0NjUiLCJBWTBGTlQwZm9WV0FyVnZzMEV1Mm9LOHJmRDZ1SjF0Vk52WTU0VzB2Il0="
	publicKey := "<RSAKeyValue><Modulus>khbyu3/vAEBHi339fTuo2nUaQgSTBj0jvpt5xnLTTF35FLkGI+5Z3wiKfnvQiCLf+5s4r8JB/Uic/i6/iNjPMILlFeE0N6XZ+2pkgwRkfMOcx6eoewypTPUoPpzuAINJxJRpHym3V6ZJZ1UfYvzRcQBD/lBeAYrvhpCwukQMkGushKsOS6U+d+2C9ZNeP+U+uwuv/xu8YBCBAgGb8YdNojcGzM4SbCtwvJ0fuOfmCWZvUoiumfE4x7rAhp1pa9OEbUe0a5HL+1v7+JLBgkNZ7Z2biiHaM6za7GjHCXU8rojatEQER+MpgDuQV3ZPx8RKRdiJgPnz9ApBHFYDHLDzDw==</Modulus><Exponent>AQAB</Exponent></RSAKeyValue>"

	licenseKey, err := cryptolens.KeyActivate(token, cryptolens.KeyActivateArguments{
		ProductId:   3646,
		Key:         "MPDWY-PQAOW-FKSCH-SGAAU",
		MachineCode: "289jf2afs3",
	})
	if err != nil || !licenseKey.HasValidSignature(publicKey) {
		return "", errors.New("Initial license key activation failed")
	}

	serialized, err := licenseKey.ToBytes()
	if err != nil {
		return "", err
	}

	f, err := ioutil.TempFile("", "cryptolens_example_offline_")
	if err != nil {
		return "", err
	}
	defer f.Close()

	_, err = f.Write(serialized)
	if err != nil {
		return "", err
	}

	return f.Name(), nil
}

func main() {
	publicKey := "<RSAKeyValue><Modulus>khbyu3/vAEBHi339fTuo2nUaQgSTBj0jvpt5xnLTTF35FLkGI+5Z3wiKfnvQiCLf+5s4r8JB/Uic/i6/iNjPMILlFeE0N6XZ+2pkgwRkfMOcx6eoewypTPUoPpzuAINJxJRpHym3V6ZJZ1UfYvzRcQBD/lBeAYrvhpCwukQMkGushKsOS6U+d+2C9ZNeP+U+uwuv/xu8YBCBAgGb8YdNojcGzM4SbCtwvJ0fuOfmCWZvUoiumfE4x7rAhp1pa9OEbUe0a5HL+1v7+JLBgkNZ7Z2biiHaM6za7GjHCXU8rojatEQER+MpgDuQV3ZPx8RKRdiJgPnz9ApBHFYDHLDzDw==</Modulus><Exponent>AQAB</Exponent></RSAKeyValue>"

	filename, err := ActivateAndSaveLicenseKey()
	if err != nil {
		fmt.Println("Failed to activate or save license key")
		return
	}

	fmt.Printf("License key saved to file %s\n\n", filename)

	savedKeyBytes, err := ioutil.ReadFile(filename)
	if err != nil {
		fmt.Println("Failed to read saved license key")
		return
	}

	licenseKey, err := cryptolens.KeyFromBytes(savedKeyBytes)
	if err != nil || !licenseKey.HasValidSignature(publicKey) {
		fmt.Println("Error in saved license key")
		return
	}

	fmt.Printf("License key sucessfully loaded from file!\n")

	if time.Now().After(licenseKey.Expires) {
		fmt.Println("License key has expired")
		return
	}

	if licenseKey.F1 {
		fmt.Println("Welcome! Pro version enabled!")
	} else {
		fmt.Println("Welcome!")
	}

}