Site icon Flutter Packages | Pub dev Packages – Flutter Mobile App World

Cross-platform ‘dart:html’

Flutterappworld

Introduction

A cross-platform dart:html:

The project is licensed under the Apache License 2.0. Some of the source code was adopted from the original dart:html in Dart SDK, which is documented in the relevant files.

Documentation

Similar projects

Getting started

1. Add dependency

In pubspec.yaml:

dependencies:
  universal_html: ^2.2.2

2. Use

import "package:universal_html/html.dart";

void main() {
  // Create a DOM tree
  final div = DivElement();
  div.append(Element.tag("h1")
    ..classes.add("greeting")
    ..appendText("Hello world!"));

  // Print outer HTML
  print(div.outerHtml);
  // --> <div><h1>Hello world</h1></div>

  // Do a CSS query
  print(div.querySelector("div > .greeting").text);
  // --> Hello world
}

Examples

Parsing HTML

Use parseHtmlDocument:

import 'package:universal_html/parsing.dart';

void main() {
  final htmlDocument = parseHtmlDocument('<html>...</html>');
}

Parsing XML

Use parseXmlDocument:

import 'package:universal_html/parsing.dart';

void main() {
  final xmlDocument = parseXmlDocument('<xml>...</xml>');
}

Scraping a website

Load a Window with WindowController:

import 'dart:io' show Cookie;
import 'package:universal_html/controller.dart';

Future main() async {
  // Load a document.
  final controller = WindowController();
  controller.defaultHttpClient.userAgent = 'My Hacker News client';
  await controller.openHttp(
    method: 'GET',
    uri: Uri.parse("https://news.ycombinator.com/"),
    onRequest: (HttpClientRequest request) {
      // Add custom headers
      request.headers.set('Authorization', 'headerValue');
      request.cookies.add(Cookie('cookieName', 'cookieValue'));
    },
    onResponse: (HttpClientResponse response) {
      print('Status code: ${response.statusCode}');
    },
  );

  // Select the top story using a CSS query
  final titleElements = controller.document.querySelectorAll(".athing > .title");
  final topStoryTitle = titleElements.first.text;

  // Print result
  print("Top Hacker News story is: $topStoryTitle");
}

EventSource

EventSource (see mozilla.org) is a browser API for reading “application/event-stream” streams. It has been supported by browsers for a long time.

import 'package:universal_html/html.dart';

Future<void> main() async {
  final eventSource = EventSource('http://example.com/events');
  await for (var message in event.onMessage) {
    print('Event type: ${message.type}');
    print('Event data: ${message.data}');
  }
}

EventSource requests from real browsers are typically authenticated using cookies. If you want to add cookies or customize other HTTP headers, you need to use EventSourceOutsideBrowser:

import 'package:universal_html/universal_html.dart';
import 'dart:io' show Cookie;

Future<void> main() async {
  final eventSource = EventSource('http://example.com/events');
  
  // The following block will NOT be executed in browsers.
  // Because compiler can infer instances of EventSourceOutsideBrowser are never constructed,
  // it will not appear in Javascript either.
  if (eventSource is EventSourceOutsideBrowser) {
    eventSource.onHttpClientRequest = (eventSource, request) {
      request.headers.set('Authorization', 'example');
      request.cookies.add(Cookie('name', 'value'));
    };
    eventSource.onHttpClientResponse = (eventSource, request, response) {
      // ...
    };
  }
  
  await for (var message in eventSource.onMessage) {
    print('Event:');
    print('  type: ${message.type}');
    print('  data: ${message.data}');
  }
}

Testing

import 'package:universal_html/controller.dart';
import 'package:test/test.dart';

void main() {
  setUp(() {
    WindowController.instance = WindowController();
  });
  
  test('test #1', () {
    // ...
  });
  
  test('test #2', () {
    // ...
  });
}

Download source code on GitHub

Cross-platform 'dart:html'.
https://github.com/dint-dev/universal_html
63 forks.
201 stars.
27 open issues.

Recent commits:

Exit mobile version