User token

User token generation in Go for the Tanker SDK.

Installation

go get github.com/TankerHQ/user-token-go/usertoken

This library depends on libsodium and libsodium-go.

As a setup example, you can check the ci/install.sh script we use to run tests in Travis.

Usage

The server-side code below demonstrates a typical flow to safely deliver user tokens to your users:

import (
    "github.com/TankerHQ/user-token-go/usertoken"
)

config := usertoken.Config {
    TrustchainID: "<trustchain-id>",
    TrustchainPrivateKey: "<trustchain-private-key>",
}

// Example server-side function in which you would implement checkAuth(),
// retrieveUserToken() and storeUserToken() to use your own authentication
// and data storage mechanisms:
func getUserToken(string userID) (string, error) {
    isAuthenticated := checkAuth(userID)

    // Always ensure userID is authenticated before returning a user token
    if ! isAuthenticated {
      return "", error.New("Unauthorized")
    }

    // Retrieve a previously stored user token for this user
    userToken := retrieveUserToken(userID)

    // If not found, create a new user token
    if userToken == "" {
        userToken, err = usertoken.Generate(config, userID)
        if err != nil {
            return "", err
        }

        // Store the newly generated user token
        storeUserToken(userID, userToken)
    }

    // From now, the same user token will always be returned to a given user
    return userToken, nil
}

Read more about user tokens in the Tanker guide.

Development

Run tests:

go test ./... -test.v

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/TankerHQ/user-token-go.