LBDS ANDROID MESSAGING

Set of Android objects to have a Intent based asynchronous communication between SORMAS and LBDS

Requirements

• java 8 +
• maven 3.6 +
• Android platform level 24

Build

The component is built with maven

AAR build to make use in android

'mvn clean install -PyourProfile'

Location of your SDK

There is a profile for each operating system in the pom.xml. You may add a profile for your needs. Or you modify the path matching the exact location of your Android SDK

Using Messaging Lib to communicate with LBDS

Configuration steps needed

TODO: verify client side configuration

Program steps needed

Inside an Activity or Service

Instantiate your http call

HttpMethod method = new HttpMethod(HttpMethod.MethodType.GET, "http://www.google.com");

A very simple abstraction of the HttpMethods can be found in the lbds-http module. See https://github.com/crowdcode-de/lbds-http for details.

Create a send intent

LbdsSendIntent sendIntent = new LbdsSendIntent(method);

Fire the intent

startService(sendIntent);

Receiving Data from LBDS

After a request has been processed, the LBDS-Subsystem will emit an Intent for Sormas. This intent is named LbdsResponseIntent and it is also the location where the phsyical receiver configuration - like package and app name - is configured.

Preconfiguration

android-manifest.xml

A receiver for the intent must be implemented.

<service android:name=".LbdsRecevierComponent" android:enabled="true" android:exported="true"> <intent-filter> <action android:name="android.intent.action.SEND" /> <category android:name="android.intent.category.DEFAULT" /> </intent-filter> <service>

The current package for SORMAS has been taken from github and was set to de.symeda.sormas.app - this may be subject to change The current Receiver Component was set to de.symeda.sormas.app.LbdsRecevierComponent - this also may be subject of a change

Receiver implementation

A receiver implementation must be located in the a.m. package and it must implement an IntentService

public class LbdsRecevierComponent extends IntentService ...

Key Exchange Functionality

In order to exchange public Keys for encrypting transport data between SORMAS and LBDS there is a key exchange functionality (kex).

• Every KEX Intent will contain ONE key when emitted towards a partner
• Every KEX Reply intent will containt BOTH keys when sent by the requested partner

Example:

• SORMAS emits a LbdsPropagateKexToLbdsIntent will soleley contain the SORMAS public key
• This intent is consumed by LBDS, the current public key will be replaced
• LBDS emits a LbdsPropagateKexToSormasIntent, which will contain both keys; the new SORMAS key plus the current LBDS key

A response intent always has both keys!

Useful to know

• You may use the Constants package to differ the Intent Type

final String intentType = intent.getStringExtra(Constants.INTENT_TYPE);
   if (intentType != null && !intentType.trim().isEmpty()) {
     IntentType type = IntentType.valueOf(intentType);
       switch (type) {
         case HTTP_SEND_INTENT:
           final String httpContainer = intent.getStringExtra(Constants.HTTP_CONTAINER);
             HttpContainer container = HttpContainer.deserializePackedHttpContainer(httpContainer);
             final HighLevelService highLevelService = ApplicationContext.getBean(HighLevelService.class);
             final String responder = "192.168.178.23:8080";
             final TransmissionSession session = highLevelService.submitHttpMethod(container.getMethod(), responder);
             // ...
             break;
         case KEX_TO_LBDS_INTENT:
           final String publicKey = intent.getStringExtra(Constants.SORMAS_KEY);
           final PublicKey key = KeySerializationUtil.deserializePublicKey(publicKey);
           //....
           break;
                  case HTTP_RESPONSE_INTENT:
                      break;
                  case KEX_TO_SORMAS_INTENT:
                      break;
              }
          }
        ....

To be done