How to pass headers in html string's urls (eg: src = "google.com") in webview_flutter 4.2.2

Question

I have a requirement where I need to display HTML string in webview_flutter (https://pub.dev/packages/webview_flutter) Plugin. The issue is that the html contains some urls that are not loaded because they require authorization token in header. I am using the method post controller.postRequest(HTMLString,headers: {"authToken": "value"}) but it is not working as in my understanding it is only passing header for the single request. I would really appreciate any help in resolving this.

here is the example html:

<p style=\"margin: 0px\">Hi Team,<br /></p>


    <p style=\"margin: 0px\">&nbsp;<br /></p>

        <p style=\"margin: 0px\">Kindly create new Subcategory as TNA360 under

            Systems<span class=\"font\" style=\"font-family: Wingdings\">à</span> Business Application.<br /></p>

            <p style=\"margin: 0px\">

                <img width=\"11.2333in\" height=\"3in\" style=\"width: 11.2333in; height: 3in\" id=\"Picture_x0020_4\" src=\"url of the image\" />

Answer 1

I finally managed to do it using this package https://pub.dev/packages/flutter_inappwebview

here is the full example code

import 'dart:convert';

import 'package:flutter/material.dart';

import 'package:flutter_inappwebview/flutter_inappwebview.dart';

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

class CustomWebView extends StatefulWidget {

  CustomWebView();

  @override
  _CustomWebViewState createState() => _CustomWebViewState();

}

class _CustomWebViewState extends State<CustomWebView> {
  late InAppWebViewController _webViewController;

  String htmlContent = '''    your html string with images
  ''';

  @override
  Widget build(BuildContext context) {
    return InAppWebView(
      initialData: InAppWebViewInitialData(data: htmlContent),
      onWebViewCreated: (controller) {
        _webViewController = controller;
        _loadHtmlContent();
      },
    );
  }

  Future<void> _loadHtmlContent() async {
    final String contentBase64 =
    base64Encode(const Utf8Encoder().convert(htmlContent));
    final String dataUri = 'data:text/html;base64,$contentBase64';

    await _webViewController.loadUrl(urlRequest: URLRequest(url: Uri.parse(dataUri)));

    // Fetch the image URLs and pass authentication headers
    final RegExp imgRegex = RegExp(r'<img [^>]*src="([^"]+)"');
    final Iterable<Match> imgMatches = imgRegex.allMatches(htmlContent);

    for (final match in imgMatches) {
      final imageUrl = match.group(1);
      if (imageUrl != null && imageUrl.startsWith('http')) {
        final response = await http.get(Uri.parse(imageUrl), headers: {
          'Authorization': 'Bearer token', // Replace with your auth token
        });

        if (response.statusCode == 200) {
          final imageDataBase64 = base64Encode(response.bodyBytes);
          final imageDataUri = 'data:image/*;base64,$imageDataBase64';
          await _webViewController.evaluateJavascript(
            source:  'document.querySelector("img[src=\'$imageUrl\']").src = "$imageDataUri"');
        }
      }
    }
  }
}