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51Degrees Geo-Location Node.js  4.2

51Degrees Geo-Location for Node.js

gettingStarted.js

Getting started example of using the 51Degrees geo-location Cloud to determine the country for a given longitude and latitude.This example is available in full on GitHub.

To run this example, you will need to create a resource key. The resource key is used as short-hand to store the particular set of properties you are interested in as well as any associated license keys that entitle you to increased request limits and/or paid-for properties.

You can create a resource key using the 51Degrees Configurator.

Firstly require the fiftyone.geolocation modules which contain all of the pipeline specific classes we will be using in this example.

const FiftyOneDegreesGeoLocation = require('fiftyone.geolocation')

Build the geo-location pipeline using the builder that comes with the fiftyone.geolocation module and pass in the desired settings. Additional flowElements / engines can be added before the build() method is called if needed.

let pipeline = new FiftyOneDegreesGeoLocation.geoLocationPipelineBuilder({
'resourceKey': localResourceKey
}).build();

Each pipeline has an event emitter attached you can listen to to catch messages. Valid log types are info, debug, warn and error.

pipeline.on('error', console.error);

A pipeline can create a flowData element which is where evidence is added (for example from a device web request). This evidence is then processed by the pipeline through the flowData's process() method (which returns a promise to work with both syncronous and asyncronous pipelines).

Here is an example of a function that gets the country from a longitude and latidude. In some cases the country value is not meaningful so instead of returning a default, a .hasValue() check can be made. Please see the failureToMatch example for more information.

let getCountry = async function (latitude, longitude) {
// Create a flow data element and process the latitude and longitude.
let flowData = pipeline.createFlowData();
// Add the longitude and latitude as evidence
flowData.evidence.add('location.latitude', latitude);
flowData.evidence.add('location.longitude', longitude);
await flowData.process();
let country = flowData.location.country;
if (country.hasValue) {
console.log(`Country: ${country.value}`);
} else {
// Echo out why the value isn't meaningful
console.log(country.noValueMessage);
}
}
/* *********************************************************************
* This Original Work is copyright of 51 Degrees Mobile Experts Limited.
* Copyright 2019 51 Degrees Mobile Experts Limited, 5 Charlotte Close,
* Caversham, Reading, Berkshire, United Kingdom RG4 7BY.
*
* This Original Work is licensed under the European Union Public Licence (EUPL)
* v.1.2 and is subject to its terms as set out below.
*
* If a copy of the EUPL was not distributed with this file, You can obtain
* one at https://opensource.org/licenses/EUPL-1.2.
*
* The 'Compatible Licences' set out in the Appendix to the EUPL (as may be
* amended by the European Commission) shall be deemed incompatible for
* the purposes of the Work and the provisions of the compatibility
* clause in Article 5 of the EUPL shall not apply.
*
* If using the Work as, or as part of, a network application, by
* including the attribution notice(s) required under Article 5 of the EUPL
* in the end user terms of the application under an appropriate heading,
* such notice(s) shall fulfill the requirements of that article.
* ********************************************************************* */
const FiftyOneDegreesGeoLocation = require((process.env.directory || __dirname) + '/../');
let localResourceKey;
// Check if there is a resource key in the global variable and use it if
// there is one.
try {
localResourceKey = resourceKey;
} catch (e) {
if (e instanceof ReferenceError) {}
}
// You need to create a resource key at https://configure.51degrees.com and
// paste it into the code, replacing !!YOUR_RESOURCE_KEY!!.
if (typeof localResourceKey === 'undefined' ||
localResourceKey.substr(0, 2) === '!!') {
localResourceKey = process.env.RESOURCE_KEY || '!!YOUR_RESOURCE_KEY!!';
}
if (localResourceKey.substr(0, 2) === '!!') {
console.log('You need to create a resource key at ' +
'https://configure.51degrees.com and paste it into the code, ' +
'replacing !!YOUR_RESOURCE_KEY!!.');
} else {
const pipeline = new FiftyOneDegreesGeoLocation.GeoLocationPipelineBuilder({
resourceKey: localResourceKey
}).build();
// Logging of errors and other messages. Valid logs types are info, debug, warn, error
pipeline.on('error', console.error);
const getCountry = async function (latitude, longitude) {
// Create a flow data element and process the latitude and longitude.
const flowData = pipeline.createFlowData();
// Add the longitude and latitude as evidence
flowData.evidence.add('query.51D_Pos_latitude', latitude);
flowData.evidence.add('query.51D_Pos_longitude', longitude);
await flowData.process();
const country = flowData.location.country;
if (country.hasValue) {
console.log(`Which country is the location [${latitude},${longitude}] in? ${country.value}`);
} else {
// Echo out why the value isn't meaningful
console.log(country.noValueMessage);
}
};
getCountry('51.458048', '-0.9822207999999999');
}