Connect Overview

Connect is a feature of Hub which acts as a bridge or a gateway that sits between NDL products and Web APIs A Web API is an application programming interface (API) for either a web server or a web browser, and consists of publicly exposed endpoints to a defined request-response message system, typically expressed in JSON or XML by means of an HTTP-based web server., and which accesses those Web APIs on the products’ behalf. Web APIs are configured for use using Connect Manager (see the Connect Manager topic within the separate Hub Online Help for more information) and Connect itself runs on whichever Hub agent has been set up to be the default.

Hub Server will automatically start/stop the Connect service on the appropriate agent if/when the default agent changes. To find out more about configuring Hub agents, see the Hub Agents Screen topic within the separate Hub Online Help.

Web APIs interact with applications and remote resources by transferring data back and forth between them across the web. This transferring of data involves the application sending a request An HTTP 'Request' is sent from a client to a host located on a server in order to receive the resource that it needs to build content. to the Web API for data to be retrieved from a remote resource, and when a response An HTTP 'Response' is sent by a server to a client with the aim of providing the client with the resource it requested. has been received back from it, the Web API then sends that data to the application. Requests can often be quite complex in nature due to the fact that they require headers and other parameters to be populated in a specific way. Responses can likewise be complicated as they include response codes and schemas An outline, diagram, or model used to describe the structure of different types of data. which need to be interpreted in order for data to be used.

With Connect, no direct interaction between NDL products and Web APIs is needed. Connect handles all of the prerequisites for sending and receiving data to and from Web APIs on the products’ behalf, which means that data obtained from Web APIs can be integrated into NDL projects in a simple, straightforward manner.

Connect can work with both Web APIs running on internal networks, or Web APIs which are available across the internet. Once Connect has been configured to access a particular Web API, it will contain information such as URLs The acronym for 'Unique Resource Locator' which is the address of a web page., request, and response schemas etc. The available operations An operation is a unit of a REST API which can be called and which comprises of an HTTP verb and a URL path. for that service will then be listed and will be available for selection.

Within NDL products, operations are referred to as 'Connectors'.

Applications such as Digitise Forms generate their own Datasources and Datasets after requesting operation schema information from Connect. Where data is passed to Connect from within an NDL project, Connect formats the data to send to the Web API then returns any response data that has been defined. Web APIs send data in their native format to Connect which then translates that data into a standardised row set format which is returned to the respective NDL project.

In order to use a Web API, the Connectors associated with it are imported into Digitise Forms as separate Datasources. Once the required Datasets have been retrieved, they can be mapped to fields and used alongside data acquired from other sources, if required.

If you are familiar with SQL Datasources within Digitise Forms, when Web API Connectors have been imported into your Forms project you will notice the similarity between the two in terms of the appearance of the dataset tables and how the fields contained with them are defined and laid out etc.

The advantage of using Connect for sending and retrieving data is that no complex coding or detailed configuration is required. Connect also handles Web API security (including OAuth An open standard for access delegation, commonly used as a way for internet users to grant websites or applications access to their information on other websites, but without giving them passwords.) on behalf of clients, and by storing the required security-related information on Hub Server, it allows projects to be deployed without the need for details to be re-keyed or re-submitted each time a resource needs to be accessed.