This book takes a deep dive into RESTful services and APIs. Despite being simple, REST is a fully-featured architectural style. Producing, exposing, and sustaining high-quality RESTful APIs to achieve smooth functional integration is a crucial yet challenging job for IT professionals. Predominantly, REST is implemented with the HTTP protocol. However, REST is not tied to HTTP alone. REST APIs are implemented for a resource, and the resource can be an entity or a service. These APIs provide a way to identify a resource by its URI. URIs can be used to transfer the current state of a resource representation. APIs can be represented as a set of endpoints stuffed with verbs and nouns. A verb typically represents an action, such as get, put, or delete, while the nouns indicate arguments appropriate to the action. It's always a good practice to have a mechanism to communicate error messages and successful execution. APIs have to clearly articulate their services and parameters in order to lessen developer errors. The error messages also have to be comprehensive in order to unambiguously convey what's happening to the end users.
With the widespread usage of the service paradigm, there has been a surge popularity for RESTful services, which are quite lightweight compared to SOAP services. Service-oriented application development and assembly have become the de facto standard in software engineering. For developing and deploying internet applications, leveraging RESTful services as application components has grown sharply. RESTful applications and services are fitted with compatible and competent APIs. RESTful services bring up the much-needed agility, adaptability, and simplicity for application development. APIs have become so common across IT services and business workloads. In addition, APIs are the most common elements for software infrastructure, middleware solutions, integration servers, containerization platforms, and backend database systems. APIs come as a standardization mechanism for enterprise applications to interact in a consistent and cognitive manner.
Due to the phenomenal growth of cloud-native and enabled applications, there is a need to establish a seamless and spontaneous link between enterprise and personal applications with cloud-hosted applications and data sources. Here, the REST paradigm scores well over other options. We have a bevy of programming and scripting languages for the client- and server-side applications. Not only desktop and laptop computers, but also handhelds, wearable, portables, nomadic, wireless, and mobile devices are becoming integrated with web applications. The environments become highly complicated and heterogeneous. Also, many devices and services have to collaborate to fulfill business processes. The REST paradigm comes to the rescue here. The REST concept is an abstraction for running web applications on different environments, such as Windows or Linux.
RESTful services guarantee the much-needed flexibility to host and run applications coded using different programming languages and platforms. Heterogeneous applications are being enabled to interoperate with one another through the power of RESTful services. Devices are being exposed as device services, which are being frontended with a RESTful API. Another widespread trend is that cloud applications are REST API-driven. Not only resource-intensive systems, but also resource-constraint embedded devices, are benefitting from the RESTful services paradigm in order to be connected. There are several device-centric communication and data transmission protocols, and the REST phenomenon is using them to become the favorite of service developers and users. There are several constraints imposed on this service implementation concept in order to be hugely benevolent for a number of usage scenarios.