BackgroundGeolocation.onHttp(httpEvent => {
  console.log("[http] ", httpEvent.success, httpEvent.status);
});

The BackgroundGeolocation SDK hosts its own flexible and robust native HTTP & SQLite persistence services. To enable the HTTP service, simply configure the SDK with an Config.url:

// Listen for HTTP responses.
BackgroundGeolocation.onHttp(response => {
  console.log("[http] response: ", response.success, response.status, response.responseText);
});

BackgroundGeolocation.ready({
  url: "https://my-server.com/locations",
  autoSync: true,
  autoSyncThreshold: 5,
  batchSync: true,
  maxBatchSize: 50,
  headers: {
    AUTHENTICATION_TOKEN: "23kasdlfkjlksjflkasdZIds"
  },
  params: {
    user_id: 1234
  },
  extras: {
    route_id: 8675309
  },
  locationsOrderDirection: "DESC",
  maxDaysToPersist: 14
}, state => {
  console.log("[ready] success: ", state);
});

The SDK immediately inserts each recorded location into its SQLite database. This database is designed to act as a temporary buffer for the HTTP service and the SDK strongly desires an empty database. The only way that locations are destroyed from the database are:

• Successful HTTP response from your server (200, 201, 204).
• Executing BackgroundGeolocation.destroyLocations.
• maxDaysToPersist elapses and the location is destroyed.
• maxRecordsToPersist destroys oldest record in favor of latest.

The SDK's HTTP service operates by selecting records from the database, locking them to prevent duplicate requests then uploading to your server.

• By default, the HTTP Service will select a single record (oldest first; see locationsOrderDirection) and execute an HTTP request to your Config.url.
• Each HTTP request is synchronous — the HTTP service will await the response from your server before selecting and uploading another record.
• If your server returns an error or doesn't respond, the HTTP Service will immediately halt.
• Configuring batchSync true instructs the HTTP Service to select all records in the database and upload them to your server in a single HTTP request.
• Use maxBatchSize to limit the number of records selected for each batchSync request. The HTTP service will execute synchronous HTTP batch requests until the database is empty.

The SDK's HTTP Service will upload recorded locations as JSON to your Config.url (See Location for the JSON schema) with Content-Type application/json. The data can be found by your server in the "HTTP request body".

<?php
 $json = file_get_contents('php://input');
 $data = json_decode($json);
 echo "POST /locations: " . $data;
?>

import express from 'express';
import bodyParser from 'body-parser';

const app = express();

app.use(bodyParser.json());  // <-- use body-parser

app.post('/locations', (req, res) => {
  console.log('POST /locations: ', req.body);
});

class LocationsController < ApplicationController
  def create
    data = params
    puts "POST /locations: #{data}"
  end
end

If your server does not return a 20x response (eg: 200, 201, 204), the SDK will UNLOCK that record. Another attempt to upload will be made in the future (until maxDaysToPersist) when:

• When another location is recorded.
• Application pause / resume events.
• Application boot.
• onHeartbeat events.
• onConnectivityChange events.
• [iOS] Background fetch events.

You can capture the HTTP response from your server by listening to the onHttp event.

By default, the SDK is configured for autoSync:true and will attempt to immediately upload each recorded location to your configured Config.url.

• Use autoSyncThreshold to throttle HTTP requests. This will instruct the SDK to accumulate that number of records in the database before calling upon the HTTP Service. This is a good way to conserve battery, since HTTP requests consume more energy/second than the GPS.

The SDK's HTTP Service can be summoned into action at any time via the method BackgroundGeolocation.sync.

Config.params, headers and extras

• The SDK's HTTP Service appends configured Config.params to root of the JSON data of each HTTP request.
• headers are appended to each HTTP Request.
• extras are appended to each recorded location and persisted to the database record.

Custom JSON Schema: locationTemplate and geofenceTemplate

The default HTTP JSON schema for both Location and Geofence can be overridden by the configuration options locationTemplate and geofenceTemplate, allowing you to create any schema you wish.

If you're concerned with Cellular data-usage, you can configure the plugin's HTTP Service to upload only when connected to Wifi:

BackgroundGeolocation.ready({
  autoSync: true,
  disableAutoSyncOnCellular: true
});

You can observe the plugin performing HTTP requests in the logs for both iOS and Android (See Wiki Debugging):

╔═════════════════════════════════════════════
║ LocationService: location
╠═════════════════════════════════════════════
╟─ 📍 Location[45.519199,-73.617054]
✅ INSERT: 70727f8b-df7d-48d0-acbd-15f10cacdf33
╔═════════════════════════════════════════════
║ HTTP Service
╠═════════════════════════════════════════════
✅ Locked 1 records
🔵 HTTP POST: 70727f8b-df7d-48d0-acbd-15f10cacdf33
🔵 Response: 200
✅ DESTROY: 70727f8b-df7d-48d0-acbd-15f10cacdf33

The SDK has a "Remote Procedure Call" (RPC) mechanism, allowing you to invoke commands upon the SDK's API by returing a JSON response from the server containing the key "background_geolocation": [...].

Within the returned [...], you may return one or more commands to invoke upon the SDK. Each command takes the form of an [], with a required first element String command, along with an optional second element Argument:string|boolean|number|Object depending upon the context of the command.

{
  "background_geolocation": [
    ["command1", argument:string|boolean|number|Object],
    ["command2"]
    .
    .
    .
  ]
}

The SDK will run each of these commands synchronously upon itself.

Your server could return a response telling the SDK to BackgroundGeolocation.stop:

{
  "background_geolocation": [
    ["stop"]
  ]
}

When returning just a single command, you can optionally omit the root [ ]:

{
  "background_geolocation": ["stop"]
}

The 2nd param to each action is optional but depends upon the context of the command. For example, #changePace requires a boolean argument:

{
  "background_geolocation": [
    ["changePace", true]
  ]
}

Some commands receive an { } argument, like #setConfig:

{
  "background_geolocation": ["setConfig", {"distanceFilter": 0, "locationUpdateInterval": 1000}]
}

You could tell the plugin to both #start and #changePace:

{
  "background_geolocation": [
    ["start"],
    ["changePace", true]
  ]
}