Sample Java Backend for Nexmo

This repository contains a sample backend code that demonstrates how to generate a Virgil JWT using the Java/Android SDK

Do not use this authentication in production. Requests to a /virgil-jwt endpoint must be allowed for authenticated users. Use your application authorization strategy.

Prerequisites

• Java Development Kit (JDK) 8+

For IntelliJ IDEA Ultimate run:

• IntelliJ IDEA Ultimate 2018.3.3+

If you have Community version of IDEA - go to Building a Jar section.

For building a jar:

• Maven 3+

IntelliJ IDEA Ultimate run

• git clone https://github.com/VirgilSecurity/demo-nexmo-chat-backend-java
• Open IntelliJ IDEA -> File -> New -> Project from Existing Sources, locate demo-nexmo-chat-backend-java and click open
• Select Import project from external model -> Maven, go next till Please select project SDK page
• Select in list of available JDKs 1.8.xxx version or greater. If you haven't JDK of 1.8.xxx version install it. Finish setup.
• Fill in your credentials into the demo-nexmo-chat-backend-java/src/main/resources/application.properties file.
• Run application

If server started successfully you will see in the end of logs:

: Tomcat started on port(s): 3000 (http)
: Started ServerApplication

If you get error Error:java: javacTask: source release 8 requires target release 1.8 go to IntelliJ IDEA -> Preferences -> Build, Execution, Deployment -> Compiler -> Java Compiler and select 8 in Project bytecode version field.

Get Virgil Credentials

If you don't have an account yet, sign up for one using your e-mail.

• Create new E2EEv5 application;
• Create new API Key and copy given private key;

To generate a JWT the following values are required from the steps above:

Variable Name	Description
virgil.app.id	ID of your Virgil Application.
virgil.app.private_key	Private key of your APP key that is used to sign the JWTs.
virgil.app.key_id	ID of your APP key. A unique string value that identifies your account in the Virgil Cloud.

• Replace credentials in application.properties with yours.

Get Nexmo Credentials

• Register on https://developer.nexmo.com/
• Create Nexmo Application and remember your generated private.key path
• Replace the <YOUR_APP_ID> in application.properties with your app id from the created app above:

Application created: aaaaaaaa-bbbb-cccc-dddd-0123456789ab

• Rename your Nexmo private.key to virgilnexmodemo_private.key
• Put it near application.properties file to the resourses folder

Building a Jar

Possibly, you want to build a Jar to deploy it on a remote server (e.g. Now, Heroku).

Clone

Clone the repository from GitHub.

$ git clone https://github.com/VirgilSecurity/e3kit-kotlin.git

Build sources

$ mvn clean package -DskipTests

JAR file will be build in target directory.

Run the Server

Run this command from the project's root folder:

$ java -jar target/server.jar

Now, use your client code to make a request to get a JWT from the sample backend that is working on http://localhost:3000.

You can verify the server with a command:

$ curl -X POST -H "Content-Type: application/json" \
  -d '{"identity":"my_identity"}' \
  http://localhost:3000/authenticate

The response should looks like:

{"authToken":"my_identity-b5ba1680-4d5c-4b2e-9890-a0500d3c9bfe"}

Specification

/auth/authenticate endpoint

This endpoint is an example of users authentication. It takes user identity and responds with unique token.

POST https://localhost:3000/authenticate HTTP/1.1
Content-type: application/json;

{
    "identity": "string"
}

Response:

{
    "authToken": "string"
}

/auth/virgil-jwt endpoint

This endpoint checks whether a user is authorized by an authorization header. It takes user's authToken, finds related user identity and generates a virgilToken (which is JSON Web Token) with this identity in a payload. Use this token to make authorized api calls to Virgil Cloud.

GET https://localhost:3000/virgil-jwt HTTP/1.1
Content-type: application/json;
Authorization: Bearer <authToken>

Response:

{
    "virgilToken": "string"
}

/auth/nexmo-jwt endpoint

This endpoint checks whether a user is authorized by an authorization header. It takes user's authToken, finds related user identity and generates a nexmoToken (which is JSON Web Token) with this identity in a payload. Use this token to make authorized api calls to Nexmo services.

Current implementation provides only /v1/sessions/** and /v1/conversations/** ACLs (It's enough for text chat). You can modify this server to suit your needs for example passing ACLs as a query parameters to GET request and then add requested ACLs to you JWT.

GET https://localhost:3000/virgil-jwt HTTP/1.1
Content-type: application/json;
Authorization: Bearer <authToken>

Response:

{
    "nexmoToken": "string"
}

/users/create endpoint

This endpoint checks whether a user is authorized by an authorization header. It creates a user on the Nexmo service and returns user's id and reference.

POST https://localhost:3000/authenticate HTTP/1.1
Content-type: application/json;
Authorization: Bearer <authToken>

{
    "name": "string",
    "display_name": "string"
}

Response:

{
    "id": "string",
    "href": "string"
}

Virgil JWT Generation

To generate JWT, you need to use the JwtGenerator class from the SDK.

public JwtGenerator jwtGenerator() throws CryptoException {
    VirgilCrypto crypto = new VirgilCrypto();
    PrivateKey privateKey = crypto.importPrivateKey(ConvertionUtils.base64ToBytes(this.appKey));
    AccessTokenSigner accessTokenSigner = new VirgilAccessTokenSigner();

    JwtGenerator jwtGenerator = new JwtGenerator(appId, privateKey, appKeyIdentifier,
        TimeSpan.fromTime(1, TimeUnit.HOURS), accessTokenSigner);

    return jwtGenerator;
}

Then you need to provide an HTTP endpoint which will return the JWT with the user's identity as a JSON.

For more details take a look at the AuthenticationService.java file.

License

This library is released under the 3-clause BSD License.

Support

Our developer support team is here to help you. Find out more information on our Help Center.

You can find us on Twitter or send us email support@VirgilSecurity.com.

Also, get extra help from our support team on Slack.