Francisco Ferreira

Valdemar Vicente Graciano Neto, Bruno Gabriel Araújo Lebtag, Paulo Gabriel Teixeira et al.

System-of-Systems (SoS) has consolidated itself as a special type of software-intensive systems. As such, subtypes of SoS have also emerged, such as Cyber-Physical SoS (CPSoS) that are formed essentially of cyber-physical constituent systems and Systems-of-Information Systems (SoIS) that contain information systems as their constituents. In contrast to CPSoS that have been investigated and covered in the specialized literature, SoIS still lack critical discussion about their fundamentals. The main contribution of this paper is to present those fundamentals to set an understanding of SoIS. By offering a discussion and examining literature cases, we draw an essential settlement on SoIS definition, basics, and practical implications. The discussion herein presented results from research conducted on SoIS over the past years in interinstitutional and multinational research collaborations. The knowledge gathered in this paper arises from several scientific discussion meetings among the authors. As a result, we aim to contribute to the state of the art of SoIS besides paving the research avenues for the forthcoming years.

Anson Miu, Francisco Ferreira, Nobuko Yoshida et al.

Modern web programming involves coordinating interactions between browser clients and a server. Typically, the interactions in web-based distributed systems are informally described, making it hard to ensure correctness, especially communication safety, i.e. all endpoints progress without type errors or deadlocks, conforming to a specified protocol. We present STScript, a toolchain that generates TypeScript APIs for communication-safe web development over WebSockets, and RouST, a new session type theory that supports multiparty communications with routing mechanisms. STScript provides developers with TypeScript APIs generated from a communication protocol specification based on RouST. The generated APIs build upon TypeScript concurrency practices, complement the event-driven style of programming in full-stack web development, and are compatible with the Node.js runtime for server-side endpoints and the React.js framework for browser-side endpoints. RouST can express multiparty interactions routed via an intermediate participant. It supports peer-to-peer communication between browser-side endpoints by routing communication via the server in a way that avoids excessive serialisation. RouST guarantees communication safety for endpoint web applications written using STScript APIs. We evaluate the expressiveness of STScript for modern web programming using several production-ready case studies deployed as web applications.

Anson Miu, Francisco Ferreira, Nobuko Yoshida et al.

Advancements in mobile device computing power have made interactive web applications possible, allowing the web browser to render contents dynamically and support low-latency communication with the server. This comes at a cost to the developer, who now needs to reason more about correctness of communication patterns in their application as web applications support more complex communication patterns. Multiparty session types (MPST) provide a framework for verifying conformance of implementations to their prescribed communication protocol. Existing proposals for applying the MPST framework in application developments either neglect the event-driven nature of web applications, or lack compatibility with industry tools and practices, which discourages mainstream adoption by web developers. In this paper, we present an implementation of the MPST framework for developing interactive web applications using familiar industry tools using TypeScript and the React.js framework. The developer can use the Scribble protocol language to specify the protocol and use the Scribble toolchain to validate and obtain the local protocol for each role. The local protocol describes the interactions of the global communication protocol observed by the role. We encode the local protocol into TypeScript types, catering for server-side and client-side targets separately. We show that our encoding guarantees that only implementations which conform to the protocol can type-check. We demonstrate the effectiveness of our approach through a web-based implementation of the classic Noughts and Crosses game from an MPST formalism of the game logic.