Specifying Web Interfaces for Command-Line Applications Based on OpenAPI

Abstract

Command-line applications help to deal with various different tasks, reaching from automation, text manipulation or document conversion to administrating databases or firewalls. Powerful orchestrations of those applications can be created, e.g., to build Continuous Delivery or decision support pipelines. If the functionality of those applications and their orchestrations shall be used within a service-oriented architecture or as a backend of a web application, a web-compatible interface is necessary, which is usually not provided. Thus, those applications need to be retrofitted with a web interface. In this paper, we present CL2HTTP, an approach to map command-line interfaces to HTTP interfaces using an extended form of the OpenAPI service description format. The extensions specify how HTTP requests are mapped to command-line invocations and how the command-line responses are mapped back to HTTP responses. Our approach does not require any programming to specify a web interface for command-line applications, is available for public use and supports deployment as a container or lambda function in cloud environments.