mime fixes

Author: hrishikeshrajwade

packages/devtools_app/lib/src/shared/http/http_request_data.dart

@@ -102,12 +102,14 @@ class DartIOHttpRequestData extends NetworkRequest {
             );
         _request = updated;
         final fullRequest = _request as HttpProfileRequest;
-        final responseMime =
+        var responseMime =
             responseHeaders?['content-type']?.toString().split(';').first;
         final requestMime =
             requestHeaders?['content-type']?.toString().split(';').first;
 
         if (fullRequest.responseBody != null) {
+          responseMime = normalizeContentType(responseHeaders?['content-type']);
+
           if (isTextMimeType(responseMime)) {
             _responseBody = utf8.decode(fullRequest.responseBody!);
           } else {
@@ -130,6 +132,16 @@ class DartIOHttpRequestData extends NetworkRequest {
     }
   }
 
+  //TODO check if all cases are handled correctly
+  String? normalizeContentType(dynamic header) {
+    if (header is List && header.isNotEmpty) {
+      return header.first.toString().split(';').first.trim().toLowerCase();
+    } else if (header is String) {
+      return header.split(';').first.trim().toLowerCase();
+    }
+    return null;
+  }
+
   static List<Cookie> _parseCookies(List<String>? cookies) {
     if (cookies == null) return [];
     return cookies.map((cookie) => Cookie.fromSetCookieValue(cookie)).toList();

packages/devtools_app/lib/src/shared/primitives/utils.dart

@@ -1135,9 +1135,12 @@ String devtoolsAssetsBasePath({required String origin, required String path}) {
 /// human-readable text.
 bool isTextMimeType(String? mimeType) {
   if (mimeType == null) return false;
-  return mimeType.startsWith('text/') ||
-      mimeType == 'application/json' ||
-      mimeType == 'application/javascript' ||
-      mimeType == 'application/xml' ||
-      mimeType == 'application/x-www-form-urlencoded';
+
+  // Strip charset if present
+  final cleanedMime = mimeType.split(';').first.trim().toLowerCase();
+
+  return cleanedMime.startsWith('text/') ||
+      cleanedMime == 'application/json' ||
+      cleanedMime == 'application/javascript' ||
+      cleanedMime == 'application/xml';
 }