Flutter web http request xmlhttprequest error

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Flutter Web HTTP Request XMLHttpRequest Error

When making HTTP requests in a Flutter web application using XMLHttpRequest, you may encounter an error due to CORS (Cross-Origin Resource Sharing) restrictions. This error occurs because XMLHttpRequest enforces the same-origin policy, which means that the request can only be made to the same domain as the web page.

To overcome this error, you need to enable CORS on the server-side to allow the browser to make cross-origin requests. CORS can be enabled by adding the appropriate headers to the server’s response.

Here is an example of how to enable CORS in various server-side technologies:

Node.js with Express

    
const express = require('express');
const app = express();

app.use((req, res, next) => {
  res.setHeader('Access-Control-Allow-Origin', '*');
  res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS');
  res.setHeader('Access-Control-Allow-Headers', 'Content-Type');
  next();
});

// Rest of your routes and logic

app.listen(3000, () => {
  console.log('Server running on port 3000');
});

PHP with Apache

    
header('Access-Control-Allow-Origin: *');
header('Access-Control-Allow-Methods: GET, POST, OPTIONS');
header('Access-Control-Allow-Headers: Content-Type');

Python with Django

    
# In your Django settings.py file
CORS_ORIGIN_ALLOW_ALL = True
CORS_ALLOW_METHODS = ['GET', 'POST', 'OPTIONS']
CORS_ALLOW_HEADERS = ['Content-Type']

After enabling CORS on the server, you should be able to make XMLHttpRequests without encountering any errors related to CORS restrictions.

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