API Tutorial Lesson 00 - Introduction

This section explains how VersaCloud can be operated in practice: its only public interface is designed as an API (Application Program Interface) available to front-end software plus callbacks to back-end servers.

In order to explain how all API elements and sub-elements can be combined to implement common tasks that are part of any multi-tier software solution for the cloud-computing environment, we proceed to describe VersaCloud's operation with source code examples following a Visual Basic-like syntax (because we consider it easy to read by any programmer). Note, however, that VersaCloud's API is available to any programming environment which has access to one of the communication protocols that have a front-end connector implemented.

It is also important to consider the calling and returning process depicted in Fig. 10 (which is the same for all and each API call, except for the inclusion of callbacks that apply only to specific API sets), which clearly states that each call might have a maximum of fourteen parameters (including compulsory and optional ones) and always returns a single value.

Finally, it is important to state that the operations described in the next paragraphs have been selected for a better understanding of the design and operation of VersaCloud, and just scratch the surface of possibilities its API provides (hence, this set of examples is much more like an introductory API tutorial text than a complete handbook or specification): our sequence of fourteen examples, detailed over the next pages, leads from basic type values to running a complete transaction with callbacks – which must be defined by a user who is a software developer.

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