Flutter web can't load network image from another domain - flutter

Question

I can't load network images in flutter web from other domains with API calls. getting this error
Trying to load an image from another domain? Find answers at:
https://flutter.dev/docs/development/platform-integration/web-images
ImageCodecException: Failed to load network image.
any help?

Answer 1

For being able to display your images from any other Domain or from Firebase Storage on a Flutter web page you have to configure your data for CORS.
Open the GCP console, select your project and start a cloud terminal session by clicking the >_ icon button in the top navbar.
Click the open editor button (pencil icon), then create the cors.json file.
The cors.json file should look like this:
[
{
"origin": ["*"],
"method": ["GET"],
"maxAgeSeconds": 3600
}
]
I set the origin to * which means that every website can display your images. But you can also insert the domain of your website there to restrict access.
Run gsutil cors set cors.json gs://your-bucket
If you need more information: https://cloud.google.com/storage/docs/configuring-cors

Answer 2

There are two ways to resolve this either run your app using HTML renderer or set up the CORS configuration.
1. Using HTML renderer
Taken from the docs
CORS is a mechanism that browsers use to control how one site accesses the resources of another site. It is designed such that, by default, one web-site is not allowed to make HTTP requests to another site using XHR or fetch. This prevents scripts on another site from acting on behalf of the user and from gaining access to another site’s resources without permission
When using <img>, <picture>, or <canvas>, the browser automatically blocks access to pixels when it knows that an image is coming from another site and the CORS policy disallows access to data.
Flutter has two renderers for web, canvaskit and html
When you run/build app on the flutter web it uses renderers based on the device where its running.
HTML renderer: when the app is running in a mobile browser.
CanvasKit renderer: when the app is running in a desktop browser.
auto (default) - automatically chooses which renderer to use.
The HTML renderer can load cross-origin images without extra configuration.
so you could use these commands to run and build the app.
flutter run -d chrome --web-renderer html // to run the app
flutter build web --web-renderer html --release // to generate a production build
source: https://docs.flutter.dev/development/tools/web-renderers
2. Setup CORS Configuration
Download the Google-cloud-sdk which contains a tool called gsutil
In your flutter project create a file called cors.json and add this json file which will remove all domain restrictions.
[
{
"origin": ["*"],
"method": ["GET"],
"maxAgeSeconds": 3600
}
]
Run gcloud init (located in google-cloud-sdk/bin)
Authenticate yourself by clicking the link and choose the project in the console.
finally execute gsutil cors set cors.json gs://<your-bucket-name>.appspot.com You can find your bucket name in firebase storage.
I have documented this entire process in github gists

Answer 3

i solve this issue by using html renderer
flutter build web --release --web-renderer html
or
flutter run --web-renderer html

Answer 4

for me flutter run -d chrome --web-renderer html worked.

Answer 5

Simply.. in your flutter (web/index.html) add this:

Answer 6

If you use firebase storage just follow these steps:
Open Google Cloud Console at your project
Click on console icon in top right corner
Click Open editor
Click File->New->cors.json
Place code below
[
{
"origin": ["*"],
"method": ["GET"],
"maxAgeSeconds": 3600
}
]
Then Run in console
**
gsutil cors set cors.json gs://bucket-name
**
bucket-name is the name of the storage bucket which you can find on your firebase project above the folders in the storage section

Answer 7

Add this code in your web/index.html file
<script type="text/javascript">
window.flutterWebRenderer = "html";
</script>

Answer 8

To debug quickly, instead of flutter run -d chrome --web-renderer html running from the terminal you can also add the arguments --web-renderer html on your run config. On the menu bar, navigate through Run > Edit Configurations

Answer 9

If you can't update CORS settings or add proxy, prefer CanvasKit (has better performance) over HTML renderer - could display image with platform view:
import 'dart:html';
import 'package:flutter/material.dart';
import 'dart:ui' as ui;
class MyImage extends StatelessWidget {
#override
Widget build(BuildContext context) {
String imageUrl = "image_url";
// https://github.com/flutter/flutter/issues/41563
// ignore: undefined_prefixed_name
ui.platformViewRegistry.registerViewFactory(
imageUrl,
(int _) => ImageElement()..src = imageUrl,
);
return HtmlElementView(
viewType: imageUrl,
);
}
}

Answer 10

just add cors.json in web folder
[
{
"origin": ["*"],
"method": ["GET"],
"maxAgeSeconds": 3600
}
]

Answer 11

After creating cors.json and running the commands, nothing worked!
Finally what worked was adding a script into index.html inside your web folder.
<script type="text/javascript">window.flutterWebRenderer = "html";</script>
Reference Image:

Answer 12

it seems it solved my issue by running flutter run --web-renderer html

Answer 13

This official solution worked for me on Chrome only (Source). But I had to run it first every time.
flutter run -d chrome --web-renderer html
And disabling web security also worked (Source). But the browsers will show a warning banner.
But In case you are running on a different browser than Chrome (e.g. Edge) and you want to keep 'web security' enabled.
You can change the default web renderer in settings in VS Code
File ==> Preferences ==> Settings ==> Enter 'Flutter Web' in the Search Bar ==> Set the default web renderer to html

Answer 14

For someone who uses Slim Framework, just create a .htaccess file on that folder for storing images and put this line of code
Header set Access-Control-Allow-Origin *

Answer 15

There is a two way to solve this issue :
1- Just run your flutter web with flutter run -d chrome --web-renderer html
But there is one problem when you renderer your canvas view to HTML view. So your all views like images, text, etc gone blurry(bad quality). If you sacrifice the quality so go on with the first solution.
If you don't sacrifice quality so you need to add some code to your backend site I have done with node js you can use with yours.
app.use(function(req, res, next) {
res.header("Access-Control-Allow-Origin", "*");
res.header("Access-Control-Allow-Headers",
"Origin, X-Requested-With, Content-Type, Accept"
);
next();
});
So, I chose the second solution because I don't sacrifice quality. So I provide you with my backend screenshot for better understanding hope you found your solution.

Answer 16

I had an issue while loading content from other domains which I don't have control over to change the cors settings from the server-side. I have found a work around for this problem.
STEP 1: go to C:\src\flutter\packages\flutter_tools\lib\src\web or navigate from your flutter root directory to flutter\packages\flutter_tools\lib\src\web.
STEP 2: open chrome.dart in your text editor.
STEP 3: add '--disable-web-security' under the like '--disable-extensions' as save the file.
STEP 4: run flutter clean in your project folder and run the app.
Hope this works for you.
I haven't tested my application in production yet. Adding this flag might also cause some security issues.

Answer 17

The Ultimate Solution
Use this package instead of flutter's NetworkImage.
https://pub.dev/packages/image_network
Tested on Flutter web with Canvas renderer and it works like a charm!

Answer 18

Verified answer is correct, Upvoted you man. Here's how I did it