Representational State Transfer Architectural Style Research Articles

Automated black‐box testing of nominal and error scenarios in RESTful APIs

AbstractRESTful APIs (or REST APIs for short) represent a mainstream approach to design and develop web APIs using the REpresentational State Transfer architectural style. Black‐box testing, which assumes only the access to the system under test with a specific interface, is the only viable option when white‐box testing is impracticable. This is the case for REST APIs: their source code is usually not (or just partially) available, or a white‐box analysis across many dynamically allocated distributed components (typical of a micro‐services architecture) is computationally challenging. This paper presentsRestTestGen, a novel black‐box approach to automatically generate test cases for REST APIs, based on their interface definition (an OpenAPI specification). Input values and requests are generated for each operation of the API under test with the twofold objective of testing nominal execution scenarios and error scenarios. Two distinct oracles are deployed to detect when test cases reveal implementation defects. While this approach is mainly targeting the research community, it is also of interest to developers because, as a black‐box approach, it is universally applicable across different programming languages, or in the case external (compiled only) libraries are used in a REST API. The validation of our approach has been performed on more than 100 of real‐world REST APIs, highlighting the effectiveness of the approach in revealing actual faults in already deployed services.

REST4Mobile: A framework for enhanced usability of REST services on smartphones

SummaryConsidering end‐user research and proliferation of smartphones and REpresentational State Transfer (REST) interfaces, we envisage that smartphone owners can innovate to compose applications on the small screen. This paper presents the design and evaluation of a REST service development framework (viz, REST4Mobile) with the aim to enhance the usability when consuming on smartphones. Our design process uses the usability factors identified in our previous work as primary constraints for modeling the framework and a corresponding composition tool. Thus, sample REST services are developed with and then without the framework, and usability of composing the services on smartphones is evaluated. Evaluation was conducted by deploying the component REST services, the composition tool, and the resulting composite apps on a local machine. As the task of service composition is conducted directly on the smartphone's screen, the evaluation process is designed to be repeatable on remote servers and on the cloud. Results showed that constraints can be added into the REST architectural style on the basis of the influences of domain specific terms and human cognitive capabilities on the naming and size of the Uniform Resource Identifiers (URIs). In addition, the principles embodying the framework are found to be influential factors in enhancing the usability of REST services on smartphones.

Roy T. Fielding: Understanding the REST Style

Roy T. Fielding reminisces about his PhD dissertation, which defined the Representational State Transfer architectural style. The first Web extra at http://youtu.be/w5j2KwzzB-0 is a video in which Roy T. Fielding talks with Charles Severance about his PhD dissertation, which defined the Representational State Transfer architectural style. The second Web extra at http://youtu.be/Bwvpuef79lY is an audio recording in which author Charles Severance reads his Computing Conversations column that discusses his interview with Roy T. Fielding about his PhD dissertation, which defined the Representational State Transfer architectural style.

Cloud-Sea Computing Systems: Towards Thousand-Fold Improvement in Performance per Watt for the Coming Zettabyte Era

We are entering a new era of computing, characterized by the need to handle over one zettabyte (1021 bytes, or ZB) of data. The world’s capacities to sense, transmit, store, and process information need to grow three orders of magnitude, while maintain an energy consumption level similar to that of the year 2010. In other words, we need to produce thousand-fold improvement in performance per watt. To face this challenge, in 2012 the Chinese Academy of Sciences launched a 10-year strategic priority research initiative called the Next Generation Information and Communication Technology initiative (the NICT initiative). A research thrust of the NICT program is the Cloud-Sea Computing Systems project. The main idea is to augment conventional cloud computing by cooperation and integration of the cloud-side systems and the sea-side systems, where the "sea-side" refers to an augmented client side consisting of human facing and physical world facing devices and subsystems. The Cloud-Sea Computing Systems project consists of four research tasks: a new computing model called REST 2.0 which extends the REST (representational state transfer) architectural style of Web computing to cloud-sea computing, a three-tier storage system architecture capable of managing ZB of data, a billion-thread datacenter server with high energy efficiency, and an elastic processor aiming at energy efficiency of one trillion operations per second per watt. This special section contains 12 papers produced by the Cloud-Sea Computing Systems project team, presenting research results relating to sensing and REST 2.0, the elastic processor, the hyperparallel server, and the cloud-sea storage.

Distributed applications and interoperable systems (Extended papers from DAIS’10)

This special issue contains selected papers from the 10th IFIP International Conference on Distributed Applications and Interoperable Systems (DAIS ’10), held in Amsterdam in the Netherlands on June 7–9 in 2010. For the 10th anniversary, the conference was organized for the first time in cooperation with ACM SIGSOFT and ACM SIGAPP. Furthermore, the program co-chairs Frank Eliassen and Rüdiger Kapitza initiated this special issue. The presented works address various aspects of distributed applications, including their design, implementation and operation, the supporting middleware, appropriate software engineering methodologies and tools. The selection of papers was compiled by inviting 8 out of the 17 full conference papers that were originally presented at the conference. In a three-stage review process 5 out of the 8 papers were finally accepted for this special issue. Walraven et al. 1 propose a coordination architecture for flexible and policy-driven composition of cross-organizational features in distributed service systems. The underlying approach of this architecture is to specify the features and their composition at a higher level that abstracts the internal implementation mechanisms of the organizations involved. Felber et al. 2 present a collaborative search companion system, CoFeed, that collects user search queries and that considers feedback to build user-centric and document-centric profiling information. Over time, the system constructs ranked collections of elements that maintain the required information diversity and enhance the user search experience by presenting additional results tailored to the user's interest space. Zaplata et al. 3 propose a concept for the development of future context-aware applications based on the novel approach of structured context prediction. As a framework, this approach allows integration of domain-specific knowledge and facilitates the application, combination and implementation of suitable prediction methods. Romero et al. 4 focus on home environments and propose a middleware solution, called DigiHome, that applies the Service Component Architecture (SCA) component model to integrate data and events generated by heterogeneous devices in such environments. DigiHome exploits the extensibility of SCA to incorporate the representational state transfer architectural style and, in this way, leverages on the integration of multiscale systems of systems (from wireless sensor networks to the Internet). Additionally, the platform applies complex event processing technology that detects application-specific situations. Careton et al. 5 extend the ambient-oriented programming paradigm to program radio frequency identification (RFID) applications. They considered RFID tags as intermittently connected mutable proxy objects hosted on mobile-distributed computing devices and detail their prototype implementation. We thank the editors of Software – Practice and Experience for hosting this special issue, the authors for their excellent work of extending and improving their original conference publications and especially the DAIS program committee members who served for the special issue for taking the time and providing high value feedback during the three review rounds.

Defining a call control interface for browser-based integrations using representational state transfer

While integrating telephony call control signaling into a desktop application is not a new concept, the emergence of web browser-based applications drives the need for feature parity between desktop and browser-based telephony call control applications. Desktop call control applications typically have the advantage of being able to use local protocol stacks or API libraries. A browser-based application does not have the same capabilities by default, especially when running on a constrained device. Traditional telephony call control APIs and architectures do not currently lend themselves for use with web browser-based applications without requiring some form of download which is not desirable. Is it possible to design a call control interface that can be consumed in browser-based applications natively without requiring additional downloads? Representational State Transfer (REST) is a resource oriented architectural style which, when used with HTTP as a uniform interface offers the possibility to use an existing defined set of interfaces to manipulate state transitions for resources. We propose that the REST architectural style can be used with an identified interface design methodology to define an interface for telephony call control capable of being consumed by browser-based applications. Furthermore by utilizing existing industry standards as an example, we suggest that existing standards can be extended to support browser-based integrations using REST.