http requests with dart

Question

I am trying to learn dart, experimenting with http requests from this blog.

So I installed dart on Windows but for whatever reason I cant seem to run this script:

import 'dart:html';
import 'dart:convert';



void main() {
  var data = { 'title' : 'My first post' };
  HttpRequest.request(
    'https://jsonplaceholder.typicode.com/posts',
    method: 'POST',
    sendData: json.encode(data),
    requestHeaders: {
      'Content-Type': 'application/json; charset=UTF-8'
    }
  )
  .then((resp) {
    print(resp.responseUrl);
    print(resp.responseText);           
  });
}


// Response
// https://jsonplaceholder.typicode.com/posts
// { "title": "My first post", "id": "101" }

When I run this from Windows terminal $dart run script.dart this will error:

script.dart:1:8: Error: Not found: 'dart:html'
import 'dart:html';
       ^
script.dart:8:3: Error: Undefined name 'HttpRequest'.
  HttpRequest.request(
  ^^^^^^^^^^^

But in the blog post there is a link to dart pad where the code runs just fine. Any ideas to try? Thanks for any incite

$dart --version
Dart SDK version: 2.15.1 (stable) (Tue Dec 14 13:32:21 2021 +0100) on "windows_x64"

Answer 1

Using the http package, is the preferred approach since it will work consistently on all platforms.

The same request can be made by doing the following:

import 'dart:convert';
import 'package:http/http.dart' as http;

void main() {
  var data = {'title': 'My first post'};
  http.post(
    Uri.parse('https://jsonplaceholder.typicode.com/posts'),
    headers: {'Content-Type': 'application/json; charset=UTF-8'},
    body: json.encode(data),
  ).then((resp) {
    print(resp.body);
  });
}

Although typically async/await syntax is used instead:

import 'dart:convert';
import 'package:http/http.dart' as http;

void main() async {
  var data = {'title': 'My first post'};
  var resp = await http.post(
    Uri.parse('https://jsonplaceholder.typicode.com/posts'),
    headers: {'Content-Type': 'application/json; charset=UTF-8'},
    body: json.encode(data),
  );
  print(resp.body);
}