Frontend first draft

frontend/pshared/lib/utils/http/client/io.dart

@@ -0,0 +1,55 @@
+import 'dart:io' as io show HttpClient, HttpHeaders;
+
+import 'package:http/http.dart' as http;
+import 'package:http/io_client.dart';
+
+
+const _sessionCookie = 'session_id';
+
+@override
+http.Client buildHttpClient() => _SessionClient(IOClient(io.HttpClient()));
+
+class _SessionClient extends http.BaseClient {
+  final http.Client _inner;
+  String? _sessionId;
+
+  _SessionClient(this._inner);
+
+  @override
+  Future<http.StreamedResponse> send(http.BaseRequest request) async {
+    if (_sessionId != null) {
+      request.headers[io.HttpHeaders.cookieHeader] = '$_sessionCookie=$_sessionId';
+    }
+
+    request.followRedirects = false;
+    request.maxRedirects = 0;
+
+    http.StreamedResponse response = await _inner.send(request);
+
+    _captureCookie(response.headers[io.HttpHeaders.setCookieHeader]);
+
+    while (response.isRedirect) {
+      final location = response.headers['location'];
+      if (location == null) break;
+
+      final redirected = http.Request(request.method, Uri.parse(location))
+        ..headers.addAll(request.headers)
+        ..bodyBytes = await response.stream.toBytes()
+        ..followRedirects = false
+        ..maxRedirects = 0;
+
+      response = await _inner.send(redirected);
+      _captureCookie(response.headers[io.HttpHeaders.setCookieHeader]);
+    }
+
+    return response;
+  }
+
+  void _captureCookie(String? setCookieHeader) {
+    if (setCookieHeader == null) return;
+    final match = RegExp('$_sessionCookie=([^;]+)',
+            caseSensitive: false)
+        .firstMatch(setCookieHeader);
+    if (match != null) _sessionId = match.group(1);
+  }
+}