Background HTTP

@nativescript/background-http #

ns plugin add @nativescript/background-http

Usage #

The below attached code snippets demonstrate how to use @nativescript/background-http to upload single or multiple files.

Note #

Call init before the app starts to initialize the http background service

import { init } from '@nativescript/background-http'
init()

Uploading files #

Sample code for configuring the upload session. Each session must have a unique id, but it can have multiple tasks running simultaneously. The id is passed as a parameter when creating the session (the image-upload string in the code below):

// file path and url
var file = '/some/local/file/path/and/file/name.jpg'
var url = 'https://some.remote.service.com/path'
var name = file.substr(file.lastIndexOf('/') + 1)

// upload configuration
var bghttp = require('@nativescript/background-http')
var session = bghttp.session('image-upload')
var request = {
  url: url,
  method: 'POST',
  headers: {
    'Content-Type': 'application/octet-stream'
  },
  description: 'Uploading ' + name
}

For a single file upload, use the following code:

var task = session.uploadFile(file, request);

For multiple files or to pass additional data, use the multipart upload method. All parameter values must be strings:

var params = [
   { name: "test", value: "value" },
   { name: "fileToUpload", filename: file, mimeType: "image/jpeg" }
];
var task = session.multipartUpload(params, request);

In order to have a successful upload, the following must be taken into account:

• the file must be accessible from your app. This may require additional permissions (e.g. access documents and files on the device). Usually this is not a problem - e.g. if you use another plugin to select the file, which already adds the required permissions.
• the URL must not be blocked by the OS. Android Pie or later devices require TLS (HTTPS) connection by default and will not upload to an insecure (HTTP) URL.

Upload request and task API #

The request object parameter has the following properties:

Note :- Android Notification titles/messages can be constructed with one of the following placeholder which will be replaced by the system .

Replaced with the current upload rate/speed [upload_rate]

Replaced with the current upload progress [upload_progress]

Replaced with the elapsed time [upload_elapsed_time]

The task object has the following properties and methods, that can be used to get information about the upload:

Handling upload events #

After the upload task is created you can monitor its progress using the following events:

task.on("progress", progressHandler);
task.on("error", errorHandler);
task.on("responded", respondedHandler);
task.on("complete", completeHandler);
task.on("cancelled", cancelledHandler); // Android only

Each event handler will receive a single parameter with event arguments:

// event arguments:
// task: Task
// currentBytes: number
// totalBytes: number
function progressHandler(e) {
    alert("uploaded " + e.currentBytes + " / " + e.totalBytes);
}

// event arguments:
// task: Task
// responseCode: number
// error: java.lang.Exception (Android) / NSError (iOS)
// response: net.gotev.uploadservice.ServerResponse (Android) / NSHTTPURLResponse (iOS)
function errorHandler(e) {
    alert("received " + e.responseCode + " code.");
    var serverResponse = e.response;
}


// event arguments:
// task: Task
// responseCode: number
// data: string
function respondedHandler(e) {
    alert("received " + e.responseCode + " code. Server sent: " + e.data);
}

// event arguments:
// task: Task
// responseCode: number
// response: net.gotev.uploadservice.ServerResponse (Android) / NSHTTPURLResponse (iOS)
function completeHandler(e) {
    alert("received " + e.responseCode + " code");
    var serverResponse = e.response;
}

// event arguments:
// task: Task
function cancelledHandler(e) {
    alert("upload cancelled");
}

Testing the plugin #

In order to test the plugin, you must have a server instance to accept the uploads. There are online services that can be used for small file uploads - e.g. http://httpbin.org/post However, these cannot be used for large files. The plugin repository comes with a simple server you can run locally. Here is how to start it:

cd demo-server
npm i
node server 8080

The above commands will start a server listening on port 8080. Remember to update the URL in your app to match the address/port where the server is running.

License #

Apache License Version 2.0