Programming patterns and development guidelines for Semantic Sensor Grids (SemSorGrid4Env)

The web of Linked Data holds great potential for the creation of semantic applications that can combine self-describing structured data from many sources including sensor networks. Such applications build upon the success of an earlier generation of 'rapidly developed' applications that utilised RESTful APIs. This deliverable details experience, best practice, and design patterns for developing high-level web-based APIs in support of semantic web applications and mashups for sensor grids. Its main contributions are a proposal for combining Linked Data with RESTful application development summarised through a set of design principles; and the application of these design principles to Semantic Sensor Grids through the development of a High-Level API for Observations. These are supported by implementations of the High-Level API for Observations in software, and example semantic mashups that utilise the API

Towards property-based testing of RESTful web services

Developing APIs as Web Services over HTTP implies adding an extra layer to software, compared to the ones that we would need to develop an API distributed as, for example, a library. This additional layer must be included in testing too, but this implies that the software under test has an additional complexity due both to the need to use an intermediate protocol in tests and to the need to test compliance with the constraints imposed by that protocol: in this case the constraints defined by the REST architectural style. On the other hand, these requirements are common to all the Web Services, and because of that, we should be able to abstract this aspect of the testing model so that we can reuse it in testing any Web Service. In this paper, as a first step towards automating the testing of Web Services over HTTP, we describe a practical mechanism and model for testing RESTful Web Services without side effects and give an example of how we successfully adapted that mechanism to test two different existing Web Services: Storage Room by Thriventures and Google Tasks by Google. For this task we have used Erlang together with state machine models in the property-based testing tool Quviq QuickCheck, implemented using the statem module. 1

Taming the interoperability challenges of complex IoT systems

of communication protocols and data formats; hence ensuring diverse devices can interoperate with one another remains a significant challenge. Model-driven development and testing solutions have been proposed as methods to aid software developers achieve interoperability compliance in the face of this increasing complexity. However, current approaches often involve complicated and domain specific models (e.g. web services described by WSDL). In this paper, we explore a lightweight, middleware independent, model-driven development framework to help developers tame the challenges of composing IoT services that interoperate with one another. The framework is based upon two key contributions: i) patterns of interoperability behaviour, and ii) a software framework to monitor and reason about interoperability success or failure. We show using a case-study from the FI-WARE Future Internet Service domain that this interoperability framework can support non-expert developers address interoperability challenges. We also deployed tools built atop the framework and made them available in the XIFI large-scale FI-PPP test environment

RESTful Web Services Development with a Model-Driven Engineering Approach

A RESTful web service implementation requires following the constrains inherent to Representational State Transfer (REST) architectural style, which, being a non-trivial task, often leads to solutions that do not fulfill those requirements properly. Model-driven techniques have been proposed to improve the development of complex applications. In model-driven software development, software is not implemented manually based on informal descriptions, but partial or completely generated from formal models derived from metamodels. A model driven approach, materialized in a domain specific language that integrates the OpenAPI specification, an emerging standard for describing REST services, allows developers to use a design first approach in the web service development process, focusing in the definition of resources and their relationships, leaving the repetitive code production process to the automation provided by model-driven engineering techniques. This also allows to shift the creative coding process to the resolution of the complex business rules, instead of the tiresome and error-prone create, read, update, and delete operations. The code generation process covers the web service flow, from the establishment and exposure of the endpoints to the definition of database tables.A implementação de serviços web RESTful requer que as restrições inerentes ao estilo arquitetónico “Representational State Transfer” (REST) sejam cumpridas, o que, sendo usualmente uma tarefa não trivial, geralmente leva a soluções que não atendem a esses requisitos adequadamente. Técnicas orientadas a modelos têm sido propostas para melhorar o desenvolvimento de aplicações complexas. No desenvolvimento de software orientado a modelos, o software não é implementado manualmente com base em descrições informais, mas parcial ou completamente gerado a partir de modelos formais derivados de meta-modelos. Uma abordagem orientada a modelos, materializada através de uma linguagem específica do domínio que integra a especificação OpenAPI, um padrão emergente para descrever serviços REST, permite aos desenvolvedores usar uma primeira abordagem de design no processo de desenvolvimento de serviços da Web, concentrando-se na definição dos recursos e das suas relações, deixando o processo de produção de código repetitivo para a automação fornecida por técnicas de engenharia orientadas a modelos. Isso também permite focar o processo de codificação criativo na resolução e implementação das regras de negócios mais complexas, em vez de nas operações mais repetitivas e propensas a erros: criação, leitura, atualização e remoção de dados. O processo de geração de código abrange o fluxo do serviço web desde o estabelecimento e exposição dos caminhos para os serviços disponíveis até à definição de tabelas de base de dados

Model-based Role Based Access Control for RESTful Spring applications

Mudelipõhine tarkvaraarendus on kaasaegse tarkvara arendamise metoodika, mille eesmärk on lahendada konkreetseid probleeme, luues domeeni mudelid ja pakkudes lahendust kontseptuaalsel viisil. Domeenipõhine keel (DSL) on arvuti keel, mis võimaldab lahendada probleeme konkreetses domeenis. Käesoleva lõputöö eesärgiks on arendada tarkvaraline vahend, mis aitab luua automaatselt tarkvarakoodi rolli-põhise ligipääsu kontrolli abil RESTful rakendustele. Selle jaoks soovime pakkuda spetsifikatsiooni, mis läbi DSL-i sisendi kirjeldaks andmebaasi kihtide komponente (näiteks klassid ja hoidlad), vahekihtide komponente (st Resources/Assemblers, Controllers), ja rolli-põhise ligipääsu kontrolli mudelit koos sihtrakendusega. Tuginedes reeglitele, genereerib meie vahend koodi, mis sisaldab RBAC autentimisega / autoriseerimisega seotud konfiguratsiooni ja abiklasse. See on kogu RESTful Spring Boot rakenduse tuumik koos kommentaaride ning baaskoodiga, mille sisendiks on etteantud RBAC mudel.Model-driven software development is the modern software development methodology that aims at solving a specific problem by creating the domain models and providing the solution in a conceptual way. Domain-Specific Language (DSL) is the computer language that allows solving a problem in a specific domain. The goal of this thesis is to develop a software tool that helps to generate the software codes automatically with Role Based Access Control for a RESTful application. In this context, we want to provide a resource specification as an input to the software tool through DSL for describing the database layer components (i.e. Entity classes and Repositories), the integration layer components (i.e. Resources/Assemblers, Controllers), and a Role-Based Access Control model to be associated with a target application. Based on the definitions, our tools will generate code, including RBAC authentication/authorization related configuration and helper classes. Thus, the skeleton for the RESTful Spring Boot application with the annotations and basic code to enforce the RBAC model provided as input