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The contents below is a brief description of the functionality of the NDN Gateway. Any example mentioned will be based around the ABS Address Coder. This description of the NDN Gateway consists of two main features:

Preparation for the NDN Gateway ( org.ndn.web.services.axis.gateway.request.RequestNDNGatewayHandler); and Activity at the NDN Gateway ( org.ndn.web.services.axis.gateway.NDNGateway)

Preparation for the NDN Gateway

Movement into the gateway is taken care of by a handler, the RequestNDNGatewayHandler . Here, information is extracted to be placed into the message header later on. The GUID is the first to be extracted, and is set as the SERVICE_GUID property in the MessageContext object. The username is then extracted from the MessageContext and checked whether it is null or an empty String. Should the username be null or an empty String, both the username and password are replaced by the String "anonymous". Otherwise, no action is taken. The message is now ready to be moved through the NDN Gateway.

NDN Gateway

Three main functions occur at the Gateway:

Authentication - is the user who they claim to be and a registered user? Authorization - does the user possess the required access permissions to access this particular function/resource? Re-routing - re-direction to the requested end-point once authentication and authorization have occured and are satisfied.

Movement within the NDN Gateway:

The NDN Gateway executes a chain of commands in order to fulfill the three main functions of the gateway (as stated above). Movement within the NDN Gateway occurs as illustrated below:

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Fig 1.1: Movement through the NDN Gateway.

Authentication:

Authentication, in the NDN Gateway code, is done by checking that the Member is valid (i.e. the profile exists in the system). In the case of the Address Coder, the member is required to have logged into the NDN Rich Client before being able to access the Address Coder. As a post-login procedure, the Member's user details including their username and password are recorded as a part of a "dummy Member". These details are then extracted and fed to the method, checkMemberIsValid(String, String), which makes a call to the NodeActivationFacadeRemote class. Here, a simple login is executed with the username and password as provided. Successful login here indicates that the provided details is valid. A Member object for the valid member is then returned.

Authorization:

Immediately after the member is validated, a check for the appropriate access permissions is carried out. A call to check for valid permissions is executed with the username and GUID (representing the requested resource or service) previously extracted. Here, a series of calls are made resulting a test for whether the logged in user has access permissions to resource specified (specified through use of the GUID). The Web Service object (also known as the resource) is only retrieved if the user passes this test. Should the object be "not null", the new URI will be extracted and returned as a string.

Re-directing:

The user is re-directed through the callWebService(String, Message) method. Here, a SOAP connection is established and a call to the endpoint (using the new URI) is made. This call returns a Message object which goes through a final check for any faults before it is set as the response message.

NDN Gateway - Integration

Movement in and out of the NDN Gateway occurs with the assistance of request and response handlers. These handlers are configured in a .wsdd file as shown below:

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Fig 1.2: .wsdd file specifying request handler for NDN Gateway.

As illustrated in the code above, request handlers are specified within the tags using the tag. The handler specified here is the RequestNDNGatewayHandler (as mentioned above).

Similarly, the response handler is specified within tags. Where response handlers exist, the .wsdd file will generally have the following format:

• ...
• ...

Development/Dev_NDNdataWeb Web Utilities