@awarns/wifi

This module includes tasks to obtain information regarding nearby Wi-Fi access points (APs). This is useful to assess the existence of concrete access points nearby. Also, to build custom indoor localization and positioning systems based on Wi-Fi.

This plugin acts as a wrapper on top of the nativescript-context-apis plugin (from the same authors), offering Wi-Fi scanning tasks. Scan for nearby Wi-Fi APs even in background.

Install the plugin using the following command line instruction:

ns plugin add @awarns/wifi

Usage

After installing and setting up this plugin, you'll have access to two different tasks to scan for Wi-Fi APs seen nearby. The result, will be a WifiScan record, described below.

Tasks

Task name	Description
acquirePhoneWifiScan	Allows to perform a single Wi-Fi scan for a given amount of time
acquireMultiplePhoneWifiScan	Allows to repeatedly perform Wi-Fi scans. Scans will happen for as long as there is execution time remaining (3 minutes max. or shortly before the next time-scheduled task execution, whatever occurs earlier)

Note: All the tasks require fine location permission and active Wi-Fi radio for their execution. Each task will automatically request what is missing during framework's initialization

Acquire a single Wi-Fi scan

To register this task for its use, you just need to import it and call its generator function inside your application's task list:

import { Task } from '@awarns/core/tasks';
import { acquirePhoneWifiScanTask } from '@awarns/wifi';

export const demoTasks: Array<Task> = [
    acquirePhoneWifiScanTask(/* optional */ { ensureIsNew: true, timeout: 15000 }),
];

Task generator parameters:

Name	Type	Description
ensureIsNew	boolean	Make sure that the resulting Wi-Fi scan is up-to-date. A value of true ensures Android Wi-Fi scanning restrictions are met, thus the reported value is always new. The default value is true
timeout	number	The maximum time, in milliseconds, to be spent scanning for nearby Wi-Fi APs. The default value is 15000 (15s)

Task output events:

• wifiScanAcquired

Example usage in the application task graph:

on(
  'startEvent',
  run('acquirePhoneWifiScan')
    .every(1, 'minutes')
    .cancelOn('stopEvent')
);

on('wifiScanAcquired', run('writeRecords'));

Note: To use the writeRecords task, the persistence package must be installed and configured. See persistence package docs.

Acquire Wi-Fi scans in batch

To register this task for its use, you just need to import it and call its generator function inside your application's task list:

import { Task } from '@awarns/core/tasks';
import { acquireMultiplePhoneWifiScanTask } from '@awarns/wifi';

export const demoTasks: Array<Task> = [
  acquireMultiplePhoneWifiScanTask(/* optional */ { ensureIsNew: true, timeout: 15000 }),
];

Task generator parameters:

Name	Type	Description
ensureIsNew	boolean	Make sure that the resulting Wi-Fi scans are up-to-date. A value of true ensures Android Wi-Fi scanning restrictions are met, thus the reported values are always new. The default value is true
timeout	number	The maximum time to be spent performing each individual Wi-Fi scan. The default value is 15000 (15s)

Task output events:

• wifiScanAcquired

Example usage in the application task graph:

on(
  'startEvent',
  run('acquireMultiplePhoneWifiScan', { 
     maxInterval: 25000 
     /* 
        (Optional, mandatory if ensureIsNew=true) Maximun interval between scans, unlimited by default. 
        
        If ensureIsNew=true, the value must ensure that a maximum of 2 scans are being collectd every minute. 
        
        For example, here the task will be executed every 1 minute, which means it will have ~55s to run. 
        With 25s between scans we meet the OS restrictions and have enought time to collect 2 Wi-Fi fingerprints. 
     */ 
  })
    .every(1, 'minutes')
    .cancelOn('stopEvent')
);

on('wifiScanAcquired', run('writeRecords'));

Note: To use the writeRecords task, the persistence package must be installed and configured. See persistence package docs.

Events

Name	Payload	Description
wifiScanAcquired	WifiScan | Array<WifiScan>	Indicates that one or more new Wi-Fi scan results have been acquired

Records

WifiScan

Property	Type	Description
id	string	Record's unique id
type	string	Always wifi-scan
change	Change	Always none. Scan results are returned as a whole. Intermediate results are not reported
timestamp	Date	The local time when the scan was completed
isNew	boolean	Indicates if the results of the scan are cached. This can only be false when using ensureIsNew=false option during the scans
seen	Array<WifiApInfo>	The Wi-Fi APs seen during the scan. The list can be empty. For details on the properties of the WifiApInfo object, see context-apis API docs section on Wi-Fi

License

Apache License Version 2.0