Learn What Happens When Flutter Calls an API | REST Fundamentals in Flutter

Definition

HTTP status codes are numbers returned by the server to indicate the outcome of a request. A status code of 200 means the request was successful and the server returned the expected data. Other codes, such as 404 or 500, indicate errors or issues with the request or server.

Understanding how Flutter communicates with REST APIs is essential for building responsive, data-driven apps. The process begins when your app initiates an HTTP request—such as fetching a list of items from a server. This request is sent over the internet using the HTTP protocol. The server then processes the request and sends back an HTTP response, which contains both a status code and, usually, some data. In Flutter, handling these operations is done asynchronously, allowing your app to remain responsive while waiting for the server to reply. This asynchronous handling is achieved using Dart's async and await keywords, which let you write code that waits for a result without freezing the user interface.

main.dart


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

void main() async {
  final url = Uri.parse('https://jsonplaceholder.typicode.com/posts/1');
  try {
    final response = await http.get(url);
    if (response.statusCode == 200) {
      print('Success! Data: [32m${response.body}[0m');
    } else {
      print('Failed with status: ${response.statusCode}');
    }
  } catch (e) {
    print('Error: $e');
  }
}

In this code, you use the http package to perform a GET request. The function is marked as async, which allows you to use await when calling http.get(url). This means the program pauses at that line until the response arrives, but the rest of your app stays responsive. Once the response is received, you check the statusCode property. If the status code is 200, the request was successful and you print the data. If not, you print an error message with the status code. This pattern is fundamental for handling API responses in Flutter applications.

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Section 1. Chapter 1

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Definition

main.dart


              123456789101112131415
            
import 'package:http/http.dart' as http;

void main() async {
  final url = Uri.parse('https://jsonplaceholder.typicode.com/posts/1');
  try {
    final response = await http.get(url);
    if (response.statusCode == 200) {
      print('Success! Data: [32m${response.body}[0m');
    } else {
      print('Failed with status: ${response.statusCode}');
    }
  } catch (e) {
    print('Error: $e');
  }
}

Everything was clear?

Thanks for your feedback!

Section 1. Chapter 1