Add flutter request button

Author: pimterry

.idea/compiler.xml

@@ -7,7 +7,7 @@ def keyStorePassword = System.getenv('KEYSTORE_PASSWORD')
 def keyAvailable = !!keyStorePassword
 
 android {
-    compileSdkVersion 33
+    compileSdkVersion 35
 
     defaultConfig {
         applicationId "tech.httptoolkit.pinning_demo"
@@ -64,4 +64,6 @@ dependencies {
     implementation 'androidx.preference:preference-ktx:1.1.1'
     implementation 'com.appmattus.certificatetransparency:certificatetransparency-android:2.5.18'
     implementation 'org.chromium.net:cronet-embedded:119.6045.31'
+
+    implementation project(':flutter')
 }

.idea/gradle.xml

@@ -20,6 +20,9 @@ import com.appmattus.certificatetransparency.certificateTransparencyInterceptor
 import com.appmattus.certificatetransparency.certificateTransparencyTrustManager
 import com.appmattus.certificatetransparency.installCertificateTransparencyProvider
 import com.datatheorem.android.trustkit.TrustKit
+import io.flutter.embedding.engine.FlutterEngine
+import io.flutter.embedding.engine.dart.DartExecutor
+import io.flutter.plugin.common.MethodChannel
 import kotlinx.coroutines.DelicateCoroutinesApi
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.GlobalScope
@@ -49,6 +52,9 @@ const val LETS_ENCRYPT_R3_INTERM_PK_SHA256 = "jQJTbIh0grw0/1TkHSumWb+Fs0Ggogr621
 @Suppress("UNUSED_PARAMETER")
 @DelicateCoroutinesApi
 class MainActivity : AppCompatActivity() {
+
+    private var flutterEngine: FlutterEngine? = null
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
@@ -62,6 +68,17 @@ class MainActivity : AppCompatActivity() {
             -"*.badssl.com"
             +"rsa4096.badssl.com"
         }
+
+        // Prepare the flutter engine:
+        flutterEngine = FlutterEngine(this)
+        flutterEngine!!.dartExecutor.executeDartEntrypoint(
+            DartExecutor.DartEntrypoint.createDefault()
+        )
+    }
+
+    override fun onDestroy() {
+        super.onDestroy()
+        flutterEngine?.destroy()
     }
 
     private fun onStart(@IdRes id: Int) {
@@ -478,6 +495,29 @@ class MainActivity : AppCompatActivity() {
         }
     }
 
+    fun sendFlutterRequest(view: View) {
+        onStart(R.id.flutter_request)
+
+        val channel = MethodChannel(flutterEngine!!.dartExecutor.binaryMessenger, "tech.httptoolkit.pinning_demo.flutter_channel")
+
+        println("Calling Dart method from Kotlin...")
+        channel.invokeMethod("sendRequest", "https://ecc384.badssl.com/", object : MethodChannel.Result {
+            override fun success(result: Any?) {
+                println("Success from Dart: $result")
+                onSuccess(R.id.flutter_request)
+            }
+
+            override fun error(errorCode: String, errorMessage: String?, errorDetails: Any?) {
+                println("Error: $errorCode - $errorMessage")
+                onError(R.id.flutter_request, errorMessage ?: "Unknown error")
+            }
+
+            override fun notImplemented() {
+                println("Method not implemented on Dart side.")
+            }
+        })
+    }
+
     // Manually pinned at the lowest level: creating a raw TLS connection, disabling all checks,
     // and then directly analysing the certificate that's received after connection, before doing
     // HTTP by just writing & reading raw strings. Not a good idea, but the hardest to unpin!

app/build.gradle

@@ -121,6 +121,13 @@
                 android:layout_marginBottom="10dp"
                 android:background="@android:color/darker_gray"/>
 
+            <Button
+                android:id="@+id/flutter_request"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:onClick="sendFlutterRequest"
+                android:text="Flutter request" />
+
             <Button
                 android:id="@+id/custom_raw_socket_pinned"
                 android:layout_width="match_parent"

app/src/main/java/tech/httptoolkit/pinning_demo/MainActivity.kt

@@ -0,0 +1,49 @@
+.DS_Store
+.dart_tool/
+
+.pub/
+
+.idea/
+.vagrant/
+.sconsign.dblite
+.svn/
+
+migrate_working_dir/
+
+*.swp
+profile
+
+DerivedData/
+
+.generated/
+
+*.pbxuser
+*.mode1v3
+*.mode2v3
+*.perspectivev3
+
+!default.pbxuser
+!default.mode1v3
+!default.mode2v3
+!default.perspectivev3
+
+xcuserdata
+
+*.moved-aside
+
+*.pyc
+*sync/
+Icon?
+.tags*
+
+build/
+.android/
+.ios/
+.flutter-plugins
+.flutter-plugins-dependencies
+
+# Symbolication related
+app.*.symbols
+
+# Obfuscation related
+app.*.map.json

app/src/main/res/layout/activity_main.xml

@@ -0,0 +1,10 @@
+# This file tracks properties of this Flutter project.
+# Used by Flutter tool to assess capabilities and perform upgrades etc.
+#
+# This file should be version controlled and should not be manually edited.
+
+version:
+  revision: "fcf2c11572af6f390246c056bc905eca609533a0"
+  channel: "stable"
+
+project_type: module

flutter_module/.gitignore

@@ -0,0 +1,11 @@
+# flutter_module
+
+A new Flutter module project.
+
+## Getting Started
+
+For help getting started with Flutter development, view the online
+[documentation](https://flutter.dev/).
+
+For instructions integrating Flutter modules to your existing applications,
+see the [add-to-app documentation](https://flutter.dev/to/add-to-app).

flutter_module/.metadata

@@ -0,0 +1,4 @@
+include: package:flutter_lints/flutter.yaml
+
+# Additional information about this file can be found at
+# https://dart.dev/guides/language/analysis-options

flutter_module/README.md

@@ -0,0 +1,46 @@
+import 'dart:developer' as developer;
+import 'package:flutter/services.dart';
+import 'package:flutter/widgets.dart';
+import 'package:http/http.dart' as http;
+
+void main() {
+  const MethodChannel channel = MethodChannel('tech.httptoolkit.pinning_demo.flutter_channel');
+  WidgetsFlutterBinding.ensureInitialized();
+
+  channel.setMethodCallHandler((call) async {
+    if (call.method == 'sendRequest') {
+      final urlString = call.arguments as String?;
+      if (urlString == null || urlString.isEmpty) {
+        throw PlatformException(
+          code: 'INVALID_ARGUMENT',
+          message: 'URL argument is null or empty.',
+        );
+      }
+
+      developer.log('Dart attempting to send request to: $urlString', name: 'Flutter SendRequest');
+
+      try {
+        final url = Uri.parse(urlString);
+        final response = await http.get(url);
+        developer.log('Got 200 response: ${response.statusCode}', name: 'Flutter SendRequest');
+        return 'success';
+      } on http.ClientException catch (e) {
+        developer.log('Request completed with a non-2xx status code.', name: 'Flutter SendRequest', error: e);
+        return 'success'; // We don't care about status codes
+      } catch (e, stackTrace) {
+        // Any other error:
+        developer.log(
+          'A network or parsing error occurred.',
+          name: 'Flutter SendRequest',
+          error: e,
+          stackTrace: stackTrace,
+        );
+        throw PlatformException(
+          code: 'NETWORK_ERROR',
+          message: 'Failed to send request: ${e.toString()}',
+        );
+      }
+    }
+    developer.log('Unknown method call ${call.method}', name: 'Flutter');
+  });
+}