This is a quick start guide to get the RESTful Lens up and running in the quickest and simplest possible way so you can start ingesting and transforming data straight away. For a more in-depth set of instructions go to the User Guide.
In this guide we will be setting up and running the Lens as a docker image deployed to your local machine, however we support a number of cloud deployments technologies, including full support of AWS. The RESTful Lens supports the standard endpoints that supply JSON or XML and also has an additional mode that works with endpoints that conform to the JsonApi specification (Ref. JSON:API Specification). A separate JSON config file is required depending on which mode is used. All files presented in this Quick Guide are available in our example files repository.
...
The first step in configuring the RESTful Lens is to create a mapping file. The mapping file is what creates the links between your source database and your target model (ontology). This can be created using our online Data Lens Mapping Tool utilising an intuitive web-based UI. Log in hereto get started, and select the option for RESTful Lens. Alternatively, if you wish you create your RML mapping files manually, there is a detailed step by step guide on creating one from scratch, along with a number of examples.
...
There are two types of JSON configuration files that can be used with the RESTful Lens, this depends on whether it is being used to work with a standard RESTful Endpoint, or with one that conforms to the JSON:API specification. The endpoint mode is set by specifying either json-api or rest-api under the ENDPOINT_MODE config option. By default the Lens is set to JSON:API mode, and is this approach we will take in this Quick Start Guide. Specifying a JSON config file is a mandatory requirement, and is done by providing a value for the JSON_API_CONFIG_URL or JSON_REST_CONFIG_URL configurable variables respectively.
More information about the RESTful modes can be found in the full User Guide. In addition, if you would prefer to try the Lens with ready-made example files, we have created a repository for them which you are able to clone to your local file system. In the example provided below, we have used these files pulled to the local directory /opt/Projects/DataLens/.
...
License -
LICENSEThis is the license key required to operate the Lens, request your new unique license key here.
Mapping Directory URL -
MAPPINGS_DIR_URLThis is the directory where your mapping file(s) is located. As with all directories, this can be either local or on a remote S3 bucket. Mapping files for the RESTful Lens can be created using our Mapping Config Web App and can be pushed directly to a running Lens.
For this quick start, we will use a local directory.
Output Directory URL -
OUTPUT_DIR_URLThis is the directory where all generated RDF files are saved to. This also supports local and remote URLs.
For this quick start, we will use a local directory.
Configuration JSON file URL -
JSON_API_CONFIG_URLorJSON_REST_CONFIG_URLDepending on the mode in which the Lens is set to, either one of these two variables is required to be set.
For the purposes of this quick start guide, we will be using the default mode and therefore set the
JSON_API_CONFIG_URLvariable to a value of a URL referring to the JSON configuration file.
Run Standalone Mode -
LENS_RUN_STANDALONEEach of the Lenses are designed to be run as part of a larger end-to-end system, with the end result of data being uploaded into Semantic Knowledge Graphs or Property Graphs. As part of this process, Apache Kafka message queues are used for communicating between services.
For this quick start guide, we are going to enable standalone mode by setting this value to
true, so that the Lens won't attempt to connect to external services.
Record Provenance -
RECORD_PROVOandPROV_OUTPUT_DIR_URLIn the Lenses, time-series data is supported as standard, so every time a Lens ingests some data, we add provenance information. This means that you have a full record of data over time. Allowing you to see what the state if the data was at any moment.
For this quick start, we can take two approaches. One would be to turn provenance off by setting
RECORD_PROVOtofalse, or the other is to leave it on (true by default) and set thePROV_OUTPUT_DIR_URLto a directory for your provenance RDF files to be saved to. The latter is the approach we will take in the following examples.
...
The process to trigger the ingestion of your RESTful data can be done in two ways; in addition to the RESTful service, there is also a built-in Quartz Time Scheduler. This uses a user-configurable Cron Expression to set up a time-based job scheduler which will schedule the Lens to ingest your specified data from your JSON:API or REST:API remote service periodically at fixed times, dates, or intervals. More information on this can be found in the full User Guide.