Geopoint Loopback 3 - JavaScript

Geopoint loopback 3 is a JavaScript module that provides the necessary tools for working with geographical locations in a Loopback-based application. This module extends the Loopback framework by adding geolocation support to models and APIs.

Features

• Add geolocation attributes to any model
• Support for GeoJSON and WKT data types
• Create custom remote methods for geolocation queries
• Perform geospatial queries using MongoDB
• Provide geolocation verification for API endpoints

Installation

You can install Geopoint Loopback 3 using Node Package Manager (NPM). Simply run the following command:

npm install loopback-component-geopoint

Usage

Adding Geolocation Attributes to a Model

To add geolocation attributes to a model, you need to define them in your model's JSON configuration file. For example:

{
  "name": "Location",
  "properties": {
    "name": {
      "type": "string"
    },
    "latitude": {
      "type": "number",
      "required": true
    },
    "longitude": {
      "type": "number",
      "required": true
    },
    "coordinates": {
      "type": "geopoint"
    }
  }
}

In this example, we have added a "coordinates" attribute of type "geopoint" to our Location model.

Querying for Geolocation Data

Geopoint Loopback 3 provides the tools for working with geolocation data in your APIs. You can perform geospatial queries on your data to find locations within a certain radius, for example.

To create a custom remote method for querying for geolocation data, you can use the module's GeopointQuery function. Here's an example:

module.exports = function(Location) {
  const GeopointQuery = require('loopback-component-geopoint').GeopointQuery;

  Location.remoteMethod('nearby', {
    accepts: {
      arg: 'coordinates',
      type: 'geopoint',
      required: true
    },
    returns: {
      arg: 'locations',
      type: 'array',
      root: true
    },
    http: {
      verb: 'get'
    }
  });

  Location.nearby = GeopointQuery(Location, 'coordinates', 'locations');
};

In this example, we have defined a new remote method called "nearby" that accepts a geopoint as input and returns an array of locations within a certain distance of that point.

Verifying Geolocation Data

Geopoint Loopback 3 also provides the tools to verify geolocation data in your APIs. You can ensure that geolocation data is correctly formatted and within a certain range, for example.

To add geolocation verification to an API endpoint, you can use the module's GeopointValidator function. Here's an example:

module.exports = function(Location) {
  const GeopointValidator = require('loopback-component-geopoint').GeopointValidator;

  Location.beforeRemote('create', GeopointValidator(Location, {
    lat: 'latitude',
    lng: 'longitude',
    required: true,
    within: {
      lat: [90, -90],
      lng: [180, -180]
    }
  }));
};

In this example, we have added geolocation verification to our "create" API endpoint for our Location model. We are ensuring that the latitude and longitude are required fields, and that they fall within the range of acceptable latitudes and longitudes.

Conclusion

Geopoint Loopback 3 is a powerful tool for working with geolocation data in your Loopback-based applications. With its support for geospatial queries, custom remote methods, and geolocation verification, you can easily add geolocation functionality to your APIs.