$\textcolor{#890000}{\text{THIS SDK IS IN DEVELOPMENT AND NOT READY FOR PRODUCTION USE YET!!!}}$

About the FIT-Connect Java SDK

The Java SDK for FIT-Connect enables to build clients for senders and subscribers without directly interacting with any REST-Endpoints. It provides a simple fluent API that guides through the creation and sending of a submission, as well as receiving submissions as a subscriber.

For further information, check out the official docs: FIT-Connect Documentation as well as the:

• Self-Service-Portal (Testing Environment)
• FITKO project website

Outline

• About the FIT-Connect Java SDK
• Outline
• Getting Started
  • Build Dependencies
  • Prerequisites
  • Add FIT-Connect SDK to your build
• Modules
• Setup
• API Usage for Routing
  • Finding Areas
  • Finding Destinations by service identifier and region
• API Usage for Sender
  • Hand in already encrypted submission (e.g. from frontend)
    • 1. Retrieve public encryption key:
    • 2. Send encrypted data
  • Hand in a new submission with unencrypted data
  • Read the Event-Log
  • Read the latest status of a submission
  • Validating callbacks
• API Usage for Subscriber
  • Retrieving submissions
    • List with pagination
    • List without pagination
    • Receive single submission
  • Sending events to the event-log
    • Accepting a submission
    • Rejecting a submission
  • Read the Event-Log
  • Validating callbacks
• Integration Tests
• Roadmap
• Contact
• License

Getting Started

How to set up the SDK project locally.

Build Dependencies

This section lists major frameworks/libraries used in the SDK.

• Java 11 (LTS)
• Maven 3.x
• Junit 5

FIT-Connect dependencies:

• JWKValidator 1.4.0

Further 3rd party dependencies:

• Nimbus-Jose JWT
• Spring Web/HTTP
• Jackson FasterXMl
• JCommander
• Snakeyaml
• OpenCSV

Prerequisites

• Java Runtime >= 11, check your current setup in your commandline

  java --version 

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Add FIT-Connect SDK to your build

To add a dependency on FIT-Connect using Maven, use the following:

<dependency>
  <groupId>dev.fitko.fitconnect.sdk</groupId>
  <artifactId>client</artifactId>
  <version>[Latest Version]</version>
</dependency>

With [Latest Version] of the last stable build or snapshot.

If you use a snapshot version, please add the maven snapshot repo to your pom.

<distributionManagement>
  <snapshotRepository>
  <id>ossrh</id>
  <url>https://s01.oss.sonatype.org/content/repositories/snapshots</url>
  </snapshotRepository>
</distributionManagement>

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Modules

See the projects' module documentation for more specific information:

• API Module
• Core Module
• Client Module

Setup

The following steps show how to get the SDK running

1. Create and account on the self-service portal

2. Get your sender/subscriber API-key credentials

3. Clone the sdk repo

   git clone https://git.fitko.de/fit-connect/sdk-java

4. Build the project with the included maven wrapper (no separate maven installation needed)

   ./mvnw clean install -DskipTests

5. Configure your config.yml (see template)

   • add Sender OAuth credentials from the self-service portal to SENDER section
   • add Subscriber OAuth credentials from the self-service portal to SUBSCRIBER section
   • add reference to private decryption key (JWK) to SUBSCRIBER section
   • add reference to private signature key (JWK) to SUBSCRIBER section

6. Provide config via environment variable FIT_CONNECT_CONFIG or load the config with

     final var config = ApplicationConfigLoader.loadConfig("absolute/path/to/config.yml");
     final var senderClient = ClientFactory.senderClient(config);

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API Usage for Routing

The Routing-Client allows to retrieve data about areas and services as well as their service destination. A typical workflow using the RoutingClient and SenderClient would be:

1. Find the areaId for an area via routing
2. Find the destination for a leikaKey and an areaId via routing
3. Submit a new submission to the destination using the SenderClient

Finding Areas

Areas can be searched with one or more search criteria:

final RoutingClient routingClient = ClientFactory.routingClient(config);

final var citySearchCriterion = "Leip*";
final var zipCodeSearchCriterion = "04229";

// get first 5 area results
final List<Area> areas = routingClient.findAreas(List.of(citySearchCriterion, zipCodeSearchCriterion), 0, 5);

LOGGER.info("Found {} areas", areas.size());
for (final Area area : areas){
    LOGGER.info("Area {} with id {} found", area.getName(), area.getId());
}

Finding Destinations by service identifier and region

For searching a destination the DestinationSearch.Builder is used pass a search request to the routing client. The leikaKey is mandatory, as well as (max.) one other search criterion for the area/region, like one of:

• ars amtlicher regionalschlüssel
• ags amtlicher gemeindeschlüssel
• areaId identifier of an area that can be retrieved via finding areas

final RoutingClient routingClient = ClientFactory.routingClient(config);

final DestinationSearch search = DestinationSearch.Builder()
        .withLeikaKey("99123456760610")
        .withArs("064350014014")
        .withLimit(5)
        .build();

// get first 5 route results
final List<Route> routes = routingClient.findDestinations(search);

LOGGER.info("Found {} routes for service identifier {}", routes.size(), leikaKey);
for (final Route route : routes){
    LOGGER.info("Route {} with destinationId {} found", route.getName(), route.getDestinationId());
}

API Usage for Sender

For sending submission and already encrypted submissions builder are provided to construct the necessary payload to be sent. Builders allow method chaining and guide through all necessary steps.

The examples below expect a loaded configuration via the ApplicationConfigLoader.

Hand in already encrypted submission (e.g. from frontend)

If all data, metadata and attachments are encrypted outside the SDK the sender client allows to retrieve the public key for encryption as well as sending of already encrypted payloads.

For further information on how to implement end-2-end encryption please check the FIT-Connect documentation.

1. Retrieve public encryption key:

final var destinationId = UUID.fromString("d2d43892-9d9c-4630-980a-5af341179b14");
final Optional<String> publicJwk =  ClientFactory.senderClient(config).getPublicKey(destinationId);

2. Send encrypted data

To send an encrypted submission the builder EncryptedSubmissionBuilder is needed to construct an EncryptedSubmissionPayload object. The payload can be submitted as shown below via the ClientFactory.

If optional attachments are added, the UUID needs to be provided for each attachment to be able to announce them before the submission is actually sent. This is necessary because the SDK does not have access to the already encrypted metadata that, which contains that information.

// The constructed client can be reused to send multiple submissions
final SenderClient senderClient = ClientFactory.senderClient(config);

final EncryptedSubmissionPayload frontendEncryptedPayload = EncryptedSubmissionBuilder.Builder()
        .withEncryptedAttachment(UUID.fromString("d2d43892-9d9c-4630-980a-5af341179b14"), "$encrpyt€ed @tt@chment")  // optional
        .withEncryptedData("{$encrpyt€ed json}")
        .withEncryptedMetadata("$encrpyt€ed metadata")
        .withDestination(UUID.fromString("d2d43892-9d9c-4630-980a-5af341179b14"))
        .withServiceType("Führerscheinummeldung", "urn:de:fim:leika:leistung:99400048079000")
        .build();

final SentSubmission sentSubmission = senderClient.submit(frontendEncryptedPayload);

Hand in a new submission with unencrypted data

If all data, metadata and attachments are encrypted in the sender using the SDK, the client automatically handles the encryption.

Be aware that this example is not end-2-end encrypted, see FIT-Connect documentation for details.

To send a submission the builder SubmissionBuilder is needed to construct a SubmissionPayload object. The payload can be submitted as shown below via the ClientFactory.

// The constructed client can be reused to send multiple submissions
final SenderClient senderClient = ClientFactory.senderClient(config);

final SubmissionPayload submissionPayload = SubmissionBuilder.Builder()
        .withAttachment(Path.of("path/to/attachment.txt").toFile()) // optional
        .withJsonData("{ \"foo\" : \"bar\"}")
        .withDestination(UUID.fromString("d2d43892-9d9c-4630-980a-5af341179b14"))
        .withServiceType("Führerscheinummeldung", "urn:de:fim:leika:leistung:99400048079000")
        .build();

final SentSubmission sentSubmission = senderClient.submit(submissionPayload);

Read the Event-Log

To read the event-log, destinationId and caseId are needed.

final var caseId = UUID.fromString("d2d43892-9d9c-4630-980a-5af341179b14");
final var destinationId = UUID.fromString("d2d43892-9d9c-4630-980a-5af341179b14");

final List<EventLogEntry> eventLog = ClientFactory.senderClient(config).getEventLog(caseId, destinationId);

for(EventLogEntry logEntry: eventLog) {
    LOGGER.info("Event: {}", logEntry.getEvent());
    LOGGER.info("EventId: {}", logEntry.getEventId());
    LOGGER.info("Issued at: {}", logEntry.getIssueTime());
    LOGGER.info("Issuer: {}", logEntry.getIssuer());
    LOGGER.info("CaseId: {}", logEntry.getCaseId());
    LOGGER.info("SubmissionId: {}", logEntry.getSubmissionId());
    LOGGER.info("Problems: {}", logEntry.getProblems());
}

The log contains the event, issuer and occurred problems like shown in the example output below:

 Event: https://schema.fitko.de/fit-connect/events/submit-submission
 EventId: 659bcbe7-fd53-4313-a1c3-192bccc95f94
 Issued at: Thu Dec 15 10:23:51 CET 2022
 Issuer: https://submission-api-testing.fit-connect.fitko.dev
 CaseId: cb9a5a78-0ec6-492c-b652-0d7aa5e488b0
 SubmissionId: 7502200b-f12d-4fc5-9669-ad3e3337396b
 Problems: []

Read the latest status of a submission

Instead of the entire log, the latest status for a submission can be retrieved as well.

final SentSubmission sentSubmission =  ... // persisted sent submission by sender client
final EventStatus eventStatus = ClientFactory.senderClient(config).getStatusForSubmission(sentSubmission);

LOGGER.info("Current status for submission {} => {}", sentSubmission.getSubmissionId(), eventStatus.getStatus());

The example output shows the current state of the submission after being created, following the transitions in the diagram below:

Current status for submission 43cf7163-5163-4bc8-865e-be96e271ecc3 => incomplete

Validating callbacks

When receiving callbacks from the FIT-Connect system, sender (and subscriber) of submissions have to check if the received data is valid to prevent unauthorized calls from messing with the business processes and user data. The values needed for this validation are transmitted within the received HTTP requests. FIT-Connect uses the HMAC mechanism to proof the validity of its calls.

More details on how this method works can be found here:

• https://docs.fitko.de/fit-connect/docs/details/callbacks/#callback-validation
• https://www.rfc-editor.org/rfc/rfc2104

The Java SDK provides a convenient method for validating callbacks, its usage could look like this:

final SenderClient senderClient = ClientFactory.senderClient(config);

final ValidationResult validationResult = senderClient.validateCallback("hmac", 0L, "body", "secret");

if(validationResult.hasError()){
    LOGGER.error(validationresult.getError().getMessage());
}

API Usage for Subscriber

Retrieving submissions

Submissions can be fetched by id or as a list of submissions for a specific case.

List with pagination

Limit and offset parameters allow to page through the result.

final int offset = 0;
final int limit = 100;
final var destinationId = UUID.fromString("d2d43892-9d9c-4630-980a-5af341179b14");
final Set<SubmissionForPickup> firstOneHundredSubmissions = ClientFactory.subscriberClient(config).getAvailableSubmissions(destinationId), limit, offset);

List without pagination

Listing available submissions without pagination pulls the first 500 entries.

final var destinationId= UUID.fromString("d2d43892-9d9c-4630-980a-5af341179b14");
final Set<SubmissionForPickup> submissions = ClientFactory.subscriberClient(config).getAvailableSubmissions(destinationId);

Receive single submission

final submissionId = UUID.fromString("d2d43892-9d9c-4630-980a-5af341179b14");
final ReceivedSubmission receivedSubmission =  ClientFactory.subscriberClient(config).requestSubmission(submissionId);

Now, the received submission allows access to the decrypted data, attachments, metadata and ids

 // access data
final String data = receivedData.getData();
final URI dataSchemaUri = receivedData.getDataSchemaUri();
final MimeType mimeType = receivedData.getDataMimeType();

// access metadata
final Metadata  = receivedData.getSubmissionMetdata();

// access attachments
for(final ReceivedAttachment attachment : receivedSubmission.getAttachments()){
    final byte[] attachmentRawData = attachment.getData();
    final String originalFilename = attachment.getFilename();
    final UUID attachmentId = attachment.getAttachmentId();
}

// access further ids of submission
final UUID caseId  = receivedData.getCaseId();
final UUID submissionId  = receivedData.getSubmissionId();
final UUID destinationId  = receivedData.getDestinationId();

Sending events to the event-log

In order to accept or reject a submission, the subscriber client can send events (security-event-tokens) to the event-log. For more details please see the documentation on events and the creation of set-events.

Accepting a submission

If the functional review by the subscriber was positive, the submission can be accepted with an accept-submission event.

final var submissionId = UUID.fromString("d2d43892-9d9c-4630-980a-5af341179b14");

ClientFactory.subscriberClient(config)
        .requestSubmission(submissionId)
        .acceptSubmission();

After the accept event was sent the submission transitions into the state deleted and is removed.

Rejecting a submission

If the functional or technical review by the subscriber was negative, e.g. there is a discrepancy within the semantics of the data, the submission can be rejected with an reject-submission event. The rejection takes a list of dev.fitko.fitconnect.api.domain.model.event.problems.* as parameter to specify the problem. See the Fit-Connect documentation for more details on available (technical) problems.

final var submissionId = UUID.fromString("d2d43892-9d9c-4630-980a-5af341179b14");

final var rejectionProblems = List.of(new DataSchemaViolation());

ClientFactory.subscriberClient(config)
        .requestSubmission(submissionId)
        .rejectSubmission(rejectionProblems);

After the rejection event was sent the submission transitions into the state deleted and is removed.

Read the Event-Log

To read the event-log, destinationId and caseId are needed.

final var caseId = UUID.fromString("d2d43892-9d9c-4630-980a-5af341179b14");
final var destinationId = UUID.fromString("d2d43892-9d9c-4630-980a-5af341179b14");

final List<EventLogEntry> eventLog = ClientFactory.subscriberClient(config).getEventLog(caseId, destinationId);

for(EventLogEntry logEntry: eventLog) {
    LOGGER.info("Event: {}", logEntry.getEvent());
    LOGGER.info("EventId: {}", logEntry.getEventId());
    LOGGER.info("Issued at: {}", logEntry.getIssueTime());
    LOGGER.info("Issuer: {}", logEntry.getIssuer());
    LOGGER.info("CaseId: {}", logEntry.getCaseId());
    LOGGER.info("SubmissionId: {}", logEntry.getSubmissionId());
    LOGGER.info("Problems: {}", logEntry.getProblems());
}

The log contains the event, issuer and occurred problems like shown in the example output below:

 Event: https://schema.fitko.de/fit-connect/events/create-submission
 EventId: 659bcbe7-fd53-4313-a1c3-192bccc95f94
 Issued at: Thu Dec 15 10:23:51 CET 2022
 Issuer: https://submission-api-testing.fit-connect.fitko.dev
 CaseId: cb9a5a78-0ec6-492c-b652-0d7aa5e488b0
 SubmissionId: 7502200b-f12d-4fc5-9669-ad3e3337396b
 Problems: []

For more details please see the event-log documentation.

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Validating callbacks

The validation of callbacks works similar to the sender side (see Sender Callback Validation), but instead of the SenderClient, we use the SubscriberClient:

final SubscriberClient subscriberClient = ClientFactory.subscriberClient(config);

final ValidationResult validationResult = subscriberClient.validateCallback("hmac", 0L, "body", "secret");

if(validationResult.hasError()){
    LOGGER.error(validationresult.getError().getMessage());
}

Integration Tests

Integration tests in dev.fitko.fitconnect.client.ClientIntegrationTest run only on the CI-Server and are ignored by default locally. To run them on a local machine the following environment variables have to be set in the run-configuration of the IDE:

• SENDER_CLIENT_ID
• SENDER_CLIENT_SECRET
• SUBSCRIBER_CLIENT_ID
• SUBSCRIBER_CLIENT_SECRET
• TEST_DESTINATION_ID

Submit submissions are cleaned on every test run, please be aware that this might affect the present submissions on the destination that is configured. Currently, the tests are set up for the test-environment with:

var authBaseUrl = "https://auth-testing.fit-connect.fitko.dev";
var routingBaseUrl = "https://routing-api-testing.fit-connect.fitko.dev";
var selfServicePortalUrl = "https://portal.auth-testing.fit-connect.fitko.dev";
var submissionBaseUrl = "https://submission-api-testing.fit-connect.fitko.dev";

Roadmap

• Add auto-reject on technical errors
• Maven central release of 1.0.0

See the open issues for a full list of proposed features (and known issues).

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Contact

FIT-Connect Contact Page for further information

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License

Source code is licensed under the EUPL.

Rechtlicher Hinweis: Dieses Software Development Kit (SDK) ist dazu bestimmt, die Anbindung einer Software an die FIT-Connect-Infrastruktur zu ermöglichen. Hierfür kann das SDK in die anzubindenden Software integriert werden. Erfolgt die Integration des SDK in unveränderter Form, liegt keine Bearbeitung im Sinne der EUPL bzw. des deutschen Urheberrechts vor. Die Art und Weise der Verlinkung des SDK führt insbesondere nicht zur Schaffung eines abgeleiteten Werkes. Die unveränderte Übernahme des SDK in eine anzubindende Software führt damit nicht dazu, dass die anzubindende Software unter den Bedingungen der EUPL zu lizenzieren ist. Für die Weitergabe des SDK selbst - in unveränderter oder bearbeiteter Form, als Quellcode oder ausführbares Programm - gelten die Lizenzbedingungen der EUPL in unveränderter Weise.

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