GRLC_fork

This project is a fork of the project GRLC.
The GRLC project is available at: https://github.com/CLARIAH/grlc

What is GRLC ?
GRLC is a lightweight server that takes SPARQL queries (stored in a GitHub repository, in your local filesystem, or listed in a URL), and translates them to Linked Data Web APIs.
This enables universal access to Linked Data. Users are not required to know SPARQL to query their data, but instead can access a web API.

Fork improvements
This fork brings 2 major improvements:

• SPARQL UPDATE request are supported
• Access to queries stored in a GitLab repository

Usage details
For more details on using GRLC, see the original GRLC project and the additional examples provided below.

Table of content

• Quick start
• API configuration
  • local_api
  • url_api
  • github_api
  • gitlab_api
• Queries examples
  • Queries
  • UI
• Citation (original work)
• Contribute
• License
• Maintainer

Quick start

1. Install this package
   1. clone the repository
   2. build package: in the base folder, execute python3 setup.py build
   3. install package: in the pase folder, execute python3 setup.py install
2. Write the file config.ini
3. In the same directory of the config.ini, execute: python3 -m grlc_fork

Then you can access the GRLC UI from a Web browser (e.g. http://127.0.0.1:8088), or the GRLC API with HTTP query tools (e.g. cURL, see details provided in the GRLC Web UI).

API configuration

This application can reach SPARQL queries stored in one of this 4 locations:

• Local file system
• URL
• GitHub
• GitLab

Configuration examples for each of these are provided below.

local_api

An example of a config.ini:

[server]
host = 127.0.0.1                         ; host of the api
port = 8088                              ; port of the api
    
[endpoint]    
url = http://127.0.0.1:8890/sparql       ; url of the endpoint
user = none                              ; user of the endpoint
password = none                          ; password of the endpoint
    
[log]    
level = critical                         ; possible values: critical | error | warning | info | debug | notset
    
[api_local]    
sparql_dir = /path/to/my/queries         ; path to the folder which contains the queries

The URL for accessing the Web interface follows this schema: http://<host>:<port>/api-local
With this config.ini it gives: http://127.0.0.1:8088/api-local

url_api

An example of a config.ini:

[server]
host = 127.0.0.1                         ; host of the api
port = 8088                              ; port of the api
    
[endpoint]    
url = http://127.0.0.1:8890/sparql       ; url of the endpoint
user = none                              ; user of the endpoint
password = none                          ; password of the endpoint
    
[log]    
level = critical                         ; possible values: critical | error | warning | info | debug | notset

The URL for accessing the Web interface follows this schema: http://<host>:<port>/api-url
With this config.ini, it gives: http://127.0.0.1:8088/api-url

github_api

An example of a config.ini:

[server]
host = 127.0.0.1                         ; host of the api
port = 8088                              ; port of the api
    
[endpoint]    
url = http://127.0.0.1:8890/sparql       ; url of the endpoint
user = none                              ; user of the endpoint
password = none                          ; password of the endpoint
    
[log]    
level = critical                         ; possible values: critical | error | warning | info | debug | notset
    
[auth]    
git_access_token = xxx                   ; github token

The URL for accessing the Web interface follows this schema: http://<host>:<port>/api-github
With this config.ini, it gives: http://127.0.0.1:8088/api-github

gitlab_api

An example of a config.ini:

[server]
host = 127.0.0.1                         ; host of the api
port = 8088                              ; port of the api

[endpoint]
url = http://127.0.0.1:8890/sparql       ; url of the endpoint
user = none                              ; user of the endpoint
password = none                          ; password of the endpoint

[log]
level = critical                         ; possible values: critical | error | warning | info | debug | notset

[auth]
git_access_token = xxx                   ; github token

[api_gitlab]
gitlab_url = https://gitlab.xxx          ; gitlab url

The URL for accessing the Web interface follows this schema: http://<host>:<port>/api-gitlab
With this config.ini, it gives: http://127.0.0.1:8088/api-gitlab
You can reach a specific branch and a specific subdir: http://<host>:<port>/api-gitlab/<user-or-group>/<repository>/branch/<branch>/subdir/<subdir>

Queries examples

Queries examples provided below illustrate how both SPARQL UPDATE and typical SPARQL SELECT can be declared. The resulting GRLC UI is shown in the UI section below.

We assume the following directory structure:

|
└───my_delete.rq
└───my_insert.rq
└───my_select.rq

Queries

my_delete.rq

#+ summary: Delete A and B of ex:myGraph
#+ method: POST
#+ tags:
#+   - tag2

PREFIX ex: <http://example.org/>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>

DELETE DATA {
    GRAPH ex:myGraph {
        
        ex:ali a foaf:Person ;
               foaf:name "Alice" .
        
        ex:bob a foaf:Person ;
               foaf:name "Bob" .
    }
}

my_insert.rq

#+ summary: Insert A, B, C and D in ex:myGraph
#+ method: POST
#+ tags:
#+   - tag2

PREFIX ex: <http://example.org/>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>

INSERT DATA {
    GRAPH ex:myGraph {
        
        ex:ali a foaf:Person ;
               foaf:name "Alice" .
        
        ex:bob a foaf:Person ;
               foaf:name "Bob" .
        
        ex:car a foaf:Person ;
               foaf:name "Carl" .
        
        ex:dyl a foaf:Person ;
               foaf:name "Dylan" .
    }
}

my_select.rq

#+ summary: Get all triples from ex:myGraph
#+ method: GET
#+ tags:
#+   - tag1

PREFIX ex: <http://example.org/> 

SELECT ?s ?p ?o
FROM ex:myGraph
WHERE {
    ?s ?p ?o .
}

UI

The following screenshot shows the resulting GRLC UI with above-mentioned queries examples. Focus is set on a query involving SPARQL UPDATE features.

Citation (original work)

authors:
  -
    affiliation: "King's College London"
    family-names: Meroño-Peñuela
    given-names: Albert
    orcid: "https://orcid.org/0000-0003-4646-5842"
  -
    affiliation: "Netherlands eScience Center"
    family-names: Martinez
    given-names: Carlos
    orcid: "https://orcid.org/0000-0001-5565-7577"
cff-version: "1.0.3"
doi: 10.5281/zenodo.1064391
license: MIT
message: "If you use this software, please cite it as below."
repository-code: "https://github.com/CLARIAH/grlc"
title: "grlc: the git repository linked data API constructor"
abstract: grlc, the git repository linked data API constructor, automatically builds Web APIs using SPARQL queries stored in git repositories.
keywords:
  - "swagger-ui"
  - sparql
  - "linked-data"
  - "semantic-web"
  - "linked-data-api"
version: "1.3.7"
date-released: 2021-11-03

Contribute

Generally speaking, we aim at including the Orange-OpenSource/grlc features into the original GRLC project through pull requests. For contributions specific to Orange-OpenSource/grlc, please select one of the following:

👉 Create an issue or a [Merge Request].

👉 See TODO tags in code for things to develop or think about.

License

MIT

Maintainer

• Mihary RANAIVOSON
• Lionel TAILHARDAT
• Yoan CHABOT