feat(android): allow custom OkHttpClient via factory

.changeset/afraid-buttons-go.md

@@ -0,0 +1,5 @@
+---
+"@callstack/repack": minor
+---
+
+Allow customizing the native HTTP client used to download remote scripts: `RemoteScriptLoader.okHttpClientFactory` on Android and `ScriptManager.urlSessionFactory` on iOS (for SSL pinning, interceptors, custom headers, timeouts, etc.)

packages/repack/android/src/main/java/com/callstack/repack/RemoteScriptLoader.kt

@@ -15,7 +15,19 @@ import java.util.concurrent.TimeUnit
 
 class RemoteScriptLoader(val reactContext: ReactContext, private val nativeLoader: NativeScriptLoader) {
     private val scriptsDirName = "scripts"
-    private val client = OkHttpClient()
+    private val client: OkHttpClient by lazy(okHttpClientFactory)
+
+    companion object {
+        /**
+         * Factory used to create the [OkHttpClient] for downloading remote scripts.
+         *
+         * Set this before any remote script is loaded (e.g. in your Application's
+         * onCreate) to provide a custom client - for SSL pinning, interceptors,
+         * proxies, timeouts, etc. Defaults to a plain `OkHttpClient()`. This is the
+         * Android counterpart of `ScriptManager.urlSessionFactory` on iOS.
+         */
+        var okHttpClientFactory: () -> OkHttpClient = { OkHttpClient() }
+    }
 
     private fun getScriptFilePath(scriptUniqueId: String): String {
         return "${scriptsDirName}/$scriptUniqueId.script.bundle"

packages/repack/ios/ScriptManager.h

@@ -8,4 +8,15 @@
 @interface ScriptManager : NSObject <RCTBridgeModule>
 #endif
 
+/**
+ * Factory used to create the `NSURLSession` for downloading remote scripts.
+ *
+ * Set this before any remote script is loaded (e.g. in your AppDelegate) to
+ * provide a custom session - for SSL pinning, custom headers, proxies, timeouts,
+ * etc. Defaults to `[NSURLSession sharedSession]`. Assign `nil` to restore the
+ * default. This is the iOS counterpart of `RemoteScriptLoader.okHttpClientFactory`
+ * on Android.
+ */
+@property (class, nonatomic, copy, null_resettable) NSURLSession * (^urlSessionFactory)(void);
+
 @end

packages/repack/ios/ScriptManager.mm

@@ -23,12 +23,42 @@ @interface RCTBridge (RCTTurboModule)
 @end
 #endif
 
+static NSURLSession * (^_urlSessionFactory)(void) = nil;
+static NSURLSession *_cachedURLSession = nil;
+
 @implementation ScriptManager
 
 RCT_EXPORT_MODULE()
 
 @synthesize bridge = _bridge;
 
++ (NSURLSession * (^)(void))urlSessionFactory
+{
+  if (_urlSessionFactory == nil) {
+    _urlSessionFactory = ^NSURLSession * {
+      return [NSURLSession sharedSession];
+    };
+  }
+  return _urlSessionFactory;
+}
+
++ (void)setUrlSessionFactory:(NSURLSession * (^)(void))urlSessionFactory
+{
+  _urlSessionFactory = [urlSessionFactory copy];
+  // Invalidate the cached session so the next download picks up the new factory.
+  _cachedURLSession = nil;
+}
+
+// Lazily build (and cache) the session from the factory, mirroring Android's
+// `OkHttpClient by lazy(okHttpClientFactory)`.
+- (NSURLSession *)urlSession
+{
+  if (_cachedURLSession == nil) {
+    _cachedURLSession = ScriptManager.urlSessionFactory();
+  }
+  return _cachedURLSession;
+}
+
 #ifdef RCT_NEW_ARCH_ENABLED
 RCT_EXPORT_METHOD(loadScript
                   : (nonnull NSString *)scriptId scriptConfig
@@ -235,7 +265,7 @@ - (void)downloadAndCache:(ScriptConfig *)config completionHandler:(void (^)(NSEr
     [request setValue:@"text/plain" forHTTPHeaderField:@"content-type"];
   }
 
-  NSURLSessionDataTask *task = [[NSURLSession sharedSession]
+  NSURLSessionDataTask *task = [self.urlSession
       dataTaskWithRequest:request
         completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
           NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;

website/src/latest/api/runtime/script-manager.md

@@ -305,6 +305,83 @@ ScriptManager.shared.hooks.errorLoad(async (args) => {
 });
 ```
 
+## Customizing the native HTTP client
+
+Remote scripts are downloaded by the native side of Re.Pack - `OkHttpClient` on Android and `NSURLSession` on iOS. By default a plain client is used, but you can provide your own to customize networking behavior such as **SSL/certificate pinning**, **interceptors**, **proxies**, **custom headers**, or **timeouts**.
+
+The factory must be set **before any remote script is loaded** - the earliest app lifecycle hook is the safest place (Android `Application.onCreate`, iOS `application:didFinishLaunchingWithOptions:`). The client is created lazily and reused for all subsequent downloads.
+
+:::warning Native customization only
+
+This applies to the native HTTP client used for downloading scripts. Per-request options exposed to JavaScript (such as `headers`, `method`, `body`, `timeout` and `retry`) are still configured through the [resolver](#addresolver).
+
+:::
+
+### Android
+
+Assign a factory to `RemoteScriptLoader.okHttpClientFactory`:
+
+```kotlin
+// MainApplication.kt
+import com.callstack.repack.RemoteScriptLoader
+import okhttp3.OkHttpClient
+import java.util.concurrent.TimeUnit
+
+class MainApplication : Application(), ReactApplication {
+  override fun onCreate() {
+    super.onCreate()
+
+    RemoteScriptLoader.okHttpClientFactory = {
+      OkHttpClient.Builder()
+        .connectTimeout(30, TimeUnit.SECONDS)
+        .addInterceptor(MyAuthInterceptor())
+        // .certificatePinner(...) for SSL pinning
+        .build()
+    }
+    // ...
+  }
+}
+```
+
+### iOS
+
+Assign a factory to `ScriptManager.urlSessionFactory`. Assign `nil` to restore the default `[NSURLSession sharedSession]`.
+
+```swift
+// AppDelegate.swift
+import callstack_repack
+
+func application(
+  _ application: UIApplication,
+  didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
+) -> Bool {
+  ScriptManager.urlSessionFactory = {
+    let configuration = URLSessionConfiguration.default
+    configuration.timeoutIntervalForRequest = 30
+    configuration.httpAdditionalHeaders = ["X-Custom-Header": "value"]
+    // Pass a delegate for SSL pinning if needed.
+    return URLSession(configuration: configuration)
+  }
+  // ...
+}
+```
+
+```objc
+// AppDelegate.mm
+#import <callstack_repack/callstack_repack-Swift.h> // or "ScriptManager.h"
+
+- (BOOL)application:(UIApplication *)application
+    didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
+{
+  ScriptManager.urlSessionFactory = ^NSURLSession * {
+    NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];
+    configuration.timeoutIntervalForRequest = 30;
+    return [NSURLSession sessionWithConfiguration:configuration];
+  };
+  // ...
+}
+```
+
 ## Related
 
 - [Script](/api/runtime/script) - Utility class for generating script URLs used with resolvers