Allow CORS

Bug description: Unable to configure CORS.

To Reproduce:

App.js

import React, { Component } from 'react';
import { StyleSheet, Text, View } from 'react-native';
import { WebView } from 'react-native-webview';

// ...
class MyWebComponent extends Component {
  render() {
    return (
      <WebView
        source={{uri:"file:///android_asset/index.html"}}
        allowFileAccess={true}
        originWhitelist={["*"]}
      />
    );
  }
}

android/app/src/main/assets/index.html

<script>
fetch("test.json")
.then(() => alert("got response"))
.catch(error => alert(error.message))
</script>

android/app/src/main/assets/test.json

{
    "success": true
}

Expected behavior:

Able to request cross origin resource.

Environment:

• OS: Windows
• OS version: 10 Pro (1809)
• react-native version: 0.59
• react-native-webview version: 5.8.1

[gorvinsky]

Some more details for my case. I followed this guide to load a local React web app bundled with the React Native app.

It works fine on Android but on iOS, it encountered CORS error when the React web app tried to call a cross origin API. The error is as follow:

Failed to load resource: Cross-origin redirection to https://somedomain.com/login denied by Cross-Origin Resource Sharing policy: Origin null is not allowed by Access-Control-Allow-Origin.

And this is what the code looks like:

<WebView
    source={{ uri: indexUrl }}
    onLoadProgress={e => console.log(e.nativeEvent.progress)}
    allowsBackForwardNavigationGestures={true}
    originWhitelist={['*']}
    mixedContentMode="always"
    domStorageEnabled={true}
    allowFileAccess={true}
    allowUniversalAccessFromFileURLs={true}
    onError={syntheticEvent => {
        const { nativeEvent } = syntheticEvent;
        console.warn('WebView error: ', nativeEvent);
    }}
/>

[anjaneyulukinnara]

if anyone comes here, here is the code that worked for me allowUniversalAccessFromFileURLs= {true} for IOS