The simplest answer to this question is that a resource (aka web resource) is digital content returned by a server that is referenced by a URL.
If we want to dig a little deeper, there is a practical and academic answer to this question. Both are important.
The Practical Answer
Given that this question is being asked within the context of using OpenInsight as a source for RESTful APIs and that OpenInsight is primarily a database that is exposed through procedures that enforce business rules, a resource is most often derived from a database row. The specific column data contained in the resource will vary based on other factors. Likewise, the format of the resource (e.g., JSON, XML, etc.) can change based on the requirements of the client and the capability of the server.
It is a mistake to relate resources to database tables too closely. Doing so will restrict your ability to expose resources in ways that might not fit well within your database model. Resources and databases should be loosely coupled so each one can evolve freely without breaking how the APIs work.
Because resources are the most significant content returned from an API, we have provided the HTTP_Resource_Services module to help. By default, the SRP HTTP Framework returns resources in JSON format.
The Academic Answer
Let's also answer another question, "Why do we use the word resource?" The answer is because our method for referencing a resource, i.e., a URL, stands for Uniform Resource Locator. Since we are building web APIs that rely upon the standards for URIs (the generic of URL) and HTTP, we want to use the terms already employed.
The HTTP standards state that "a resource could be anything". The URI standards tell us that the term "is used in a general sense for whatever might be identified by a URI". While these might not seem overly helpful, they really are important because they caution us against preconceived notions of what a resource is or is not.
In our practical answer above, there is a warning about tightly binding resources to database tables. Resources can be abstractions of anything meaningful. They are often aggregates of digital information pulled from multiple sources (which is why one-to-one relationships between resources and tables is discouraged). OpenInsight developers already have some experience with this concept: Calculated Columns. A calculated column provides a way for tables to draw information from other sources, such as other OpenInsight tables, OS files, or even data stored in other database technologies.
