Re-implement request body previews on Android

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/modules/network/NetworkEventUtil.kt

@@ -17,16 +17,21 @@ import com.facebook.react.bridge.WritableMap
 import com.facebook.react.bridge.buildReadableArray
 import com.facebook.react.common.build.ReactBuildConfig
 import com.facebook.react.internal.featureflags.ReactNativeFeatureFlags
+import java.io.IOException
 import java.net.SocketTimeoutException
 import okhttp3.Headers
 import okhttp3.Protocol
 import okhttp3.Request
+import okhttp3.RequestBody
 import okhttp3.Response
+import okio.Buffer
 
 /**
  * Utility class for reporting network lifecycle events to JavaScript and InspectorNetworkReporter.
  */
 internal object NetworkEventUtil {
+  private const val MAX_BODY_PREVIEW_SIZE = 512 * 1024 // 512KB
+
   @JvmStatic
   fun onCreateRequest(devToolsRequestId: String, request: Request) {
     if (ReactNativeFeatureFlags.enableNetworkEventReporting()) {
@@ -35,9 +40,7 @@ internal object NetworkEventUtil {
 
       if (ReactBuildConfig.DEBUG) {
         // Debug build: Process request body for preview (CDP only)
-        requestBody =
-            (request.body() as? ProgressRequestBody)?.getBodyPreview()
-                ?: request.body()?.toString().orEmpty()
+        request.body()?.let { body -> requestBody = getRequestBodyPreview(body) }
       }
 
       InspectorNetworkReporter.reportRequestStart(
@@ -306,4 +309,25 @@ internal object NetworkEventUtil {
     }
     return responseHeaders
   }
+
+  private fun getRequestBodyPreview(requestBody: RequestBody): String {
+    if (requestBody.isOneShot()) {
+      return "[Preview unavailable]"
+    }
+
+    return try {
+      val buffer = Buffer()
+      requestBody.writeTo(buffer)
+
+      val size = buffer.size()
+      if (size <= MAX_BODY_PREVIEW_SIZE) {
+        buffer.readUtf8()
+      } else {
+        buffer.readUtf8(MAX_BODY_PREVIEW_SIZE.toLong()) + "... (truncated, ${size} bytes total)"
+      }
+    } catch (e: IOException) {
+      // Fallback
+      "[Preview unavailable]"
+    }
+  }
 }

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/modules/network/ProgressRequestBody.kt

@@ -78,9 +78,4 @@ internal class ProgressRequestBody(
         }
     )
   }
-
-  fun getBodyPreview(): String {
-    // TODO: Safely implement request body previews
-    return "[Preview unavailable]"
-  }
 }