Running a Sample

4.1 - Temperature Conversion Sample

• The sample below represent a self-contained SQLite database with some sample data from temperature and relative humidity, a business model to convert temperature from Celsius to Fahrenheit, also data can be passed via endpoint parameters to be converted by the example business model.

---

For simplification the following files can be found under the following repo folder: https://github.com/JCGCosta/OntologyToAPI/tree/master/example

• Ontology file with triples to a weather use case extending the OntologyToAPI framework:

# ./metadata_example.ttl

@prefix rdf:  <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix owl:  <http://www.w3.org/2002/07/owl#> .

@prefix md:  <http://www.cedri.com/OntologyToAPI-Metadata#> .
@prefix comm:  <http://www.cedri.com/OntologyToAPI-Communications#> .

@prefix ex:   <http://example.org/> .

# Class Definitions

ex:Temperature_C rdf:type owl:Class ;
          rdfs:subClassOf md:Metadata ;
          rdfs:comment "A measure of the average kinetic energy of the particles within a substance, which corresponds to its hotness or coldness." .

ex:Relative_Humidity rdf:type owl:Class ;
          rdfs:subClassOf md:Metadata ;
          rdfs:comment "The ratio of the amount of water vapor currently in the air to the maximum amount the air could hold at that specific temperature, expressed as a percentage." .

# Individuals for Metadata and Communication

ex:SQLITE_DB rdf:type owl:NamedIndividual ,
                      comm:DatabaseCommunication ;
             comm:hasConnectionString "sqlite+aiosqlite:///example.db" ;
             comm:usesTechnology "SQLITE" .

ex:Temperature_C_Source rdf:type owl:NamedIndividual ,
                      md:Source ;
             md:hasCommunicationTechnology ex:SQLITE_DB ;
             md:hasDescription "Retrieves the temperature data from a local SQLite database." ;
             md:hasQuery "SELECT temperature_c FROM weather;" .

ex:Temperature_C_MD rdf:type owl:NamedIndividual ,
                           ex:Temperature_C ;
                  md:hasSource ex:Temperature_C_Source ;
                  md:hasType "float" .

ex:Relative_Humidity_Source rdf:type owl:NamedIndividual ,
                      md:Source ;
             md:hasCommunicationTechnology ex:SQLITE_DB ;
             md:hasDescription "Retrieves the relative humidity data from a local SQLite database." ;
             md:hasQuery "SELECT r_humidity FROM weather;" .

ex:Relative_Humidity_MD rdf:type owl:NamedIndividual ,
                           ex:Relative_Humidity ;
                  md:hasSource ex:Relative_Humidity_Source ;
                  md:hasType "float" .

• Ontology file with triples to represent temperature convertion sample in the OntologyToAPI framework:

# ./bm_example.ttl

@prefix rdf:  <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix owl:  <http://www.w3.org/2002/07/owl#> .

@prefix md:  <http://www.cedri.com/OntologyToAPI-Metadata#> .
@prefix comm:  <http://www.cedri.com/OntologyToAPI-Communications#> .
@prefix bm:  <http://www.cedri.com/OntologyToAPI-BusinessModel#> .
@prefix excode:  <http://www.cedri.com/OntologyToAPI-ExternalCode#> .

@prefix ex:   <http://example.org/> .

# Class Definitions

ex:CelsiusToFahrenheitBM rdf:type owl:Class ;
                       rdfs:subClassOf bm:BusinessModel ;
                       rdfs:comment "This business model allows the convertion from Celsius to Fahrenheit." .

# Individuals for Business Models

ex:CelsiusToFahrenheit.py rdf:type owl:NamedIndividual ,
                                   excode:ExternalCode ;
                          excode:hasFunction "convert_temperature_c_to_f" ;
                          excode:hasPythonFile "bm.py" ;
                          excode:requiresLib "requests" .

ex:Temperature_P rdf:type owl:NamedIndividual ,
                          bm:Parameter ;
                 bm:hasParameterLabel "temperature_c" ;
                 bm:hasParameterType "float" .

ex:CelsiusToFahrenheit rdf:type owl:NamedIndividual ,
                                ex:CelsiusToFahrenheitBM ;
                         bm:requiresMetadata ex:Temperature_C_MD;
                         bm:hasExternalCode ex:CelsiusToFahrenheit.py ;
                         bm:hasParameter ex:Temperature_P .

• Code to have the business model implementation:

# ./bm.py

async def convert_temperature_c_to_f(data):
    if not data.metadata and data.params["temperature_c"] is None:
        return {"error": "No temperature was provided from Metadata or from the endpoint Parameters."}
    if data.params["temperature_c"] is not None:
        return {
            "original": data.params["temperature_c"],
            "converted": data.params["temperature_c"] * 9 / 5 + 32
        }
    else:
        return {
            "original": [t["temperature_c"] for t in data.metadata["Temperature_C_MD"]],
            "converted": [t["temperature_c"] * 9 / 5 + 32 for t in data.metadata["Temperature_C_MD"]]
        }

• Code to generate the API:

# ./main.py

import uvicorn
import sqlite3
from pathlib import Path
from OntologyToAPI.core.APIGenerator import APIGenerator

def configuring_a_sample_sqlite_database():
    if not Path('example.db').exists():
        with sqlite3.connect('example.db') as conn:
            cursor = conn.cursor()
            cursor.execute('''
                CREATE TABLE IF NOT EXISTS weather (
                    id INTEGER PRIMARY KEY AUTOINCREMENT,
                    temperature_c FLOAT NOT NULL,
                    r_humidity FLOAT NOT NULL
                );
            ''')
            cursor.execute("INSERT INTO weather (temperature_c, r_humidity) VALUES ('21.5', '60');")
            cursor.execute("INSERT INTO weather (temperature_c, r_humidity) VALUES ('22.0', '58');")
            cursor.execute("INSERT INTO weather (temperature_c, r_humidity) VALUES ('20.8', '65');")
            conn.commit()

if __name__ == "__main__":
    configuring_a_sample_sqlite_database()
    APIGen = APIGenerator(showLogs=True)
    APIGen.load_ontologies(paths=[
        "metadata_example.ttl",
        "bm_example.ttl"
    ])
    APIGen.serialize_ontologies()
    api_app = APIGen.generate_api_routes()
    uvicorn.run(api_app, host="127.0.0.1", port=5000)

• Your project structure should look something like this:

├── metadata_example.ttl
├── bm_example.ttl
├── bm.py
├── main.py

• Then you should be able to run the example as follows:

# To run the example, then execute:
python main.py

# You can access the API documentation at: http://localhost:5000