dio_curl_interceptor

A Flutter package providing a Dio interceptor that logs HTTP requests as cURL commands—perfect for debugging, sharing, and reproducing requests. Includes a modern Flutter UI for viewing, filtering, exporting, and managing cached cURL logs.

Features

• 🔍 Converts Dio HTTP requests to cURL commands for easy debugging and sharing.
• 💾 Caches cURL commands and responses with filtering, search, and export options.
• 🖥️ Modern Flutter widget for viewing and managing cURL logs (search, filter by status/date, export, clear, copy, etc).
• 📝 Utility methods for custom interceptors and direct use.

This package is actively maintained with ❤️ and updated regularly with improvements, bug fixes, and new features

_{Simultaneous (print the curl immediately after the request is made)}

_{Chronological (log the curl and response (error) together)}

Terminal Compatibility

Below is a compatibility table for different terminals and their support for printing and ANSI colors:

-- currently being tested

Terminal/Console	print/debugPrint	log (dart:developer)	ANSI Colors Support
VS Code Debug Console	✅	✅	✅
Android Studio Logcat	--	--	--
Android Studio Debug Tab	--	--	--
IntelliJ IDEA Console	--	--	--
Flutter DevTools Console	--	--	--
Terminal/CMD	--	--	--
PowerShell	--	--	--
Xcode Console	--	--	--

Usage

Option 1: Using the CurlInterceptor

Simple add the interceptor to your Dio instance, all done for you:

final dio = Dio();
dio.interceptors.add(CurlInterceptor()); // Simple usage with default options
// or
dio.interceptors.add(CurlInterceptor.allEnabled()); // Enable all options

You can customize the interceptor with CurlOptions and CacheOptions:

dio.interceptors.add(CurlInterceptor(
  curlOptions: CurlOptions(
    status: true, // Show status codes + name in logs
    responseTime: true, // Show response timing
    convertFormData: true, // Convert FormData to JSON in cURL output
    behavior: CurlBehavior.chronological,
    onRequest: RequestDetails(
      visible: true,
      ansi: Ansi.yellow, // ANSI color for request
    ),
    onResponse: ResponseDetails(
      visible: true,
      requestHeaders: true, // Show request headers
      requestBody: true, // Show request body
      responseBody: true, // Show response body
      responseHeaders: true, // Show response headers
      limitResponseBody: null, // Limit response body length (characters), default is null (no limit)
      ansi: Ansi.green, // ANSI color for response
    ),
    onError: ErrorDetails(
      visible: true,
      requestHeaders: true,
      requestBody: true,
      responseBody: true,
      responseHeaders: true,
      limitResponseBody: null,
      ansi: Ansi.red, // ANSI color for errors
    ),
    // Configure pretty printing options
    prettyConfig: PrettyConfig(
      blockEnabled: true, // Enable pretty printing
      colorEnabled: true, // Force enable/disable colored
      emojiEnabled: true, // Enable/disable emoji
      lineLength: 100, // Set the length of separator lines
    ),
    // Custom printer function to override default logging behavior
    printer: (String text) {
      // do whatever you want with the text
      // ...
      // Your custom logging implementation
      print('Custom log: $text'); // remember to print the text
    },
  ),
))

Option 2: Using CurlUtils directly in your own interceptor

If you prefer to use the utility methods in your own custom interceptor, you can use CurlUtils directly:

class YourInterceptor extends Interceptor {
  @override
  void onRequest(RequestOptions options, RequestInterceptorHandler handler) {
    // ... your request handling logic (like adding headers, modifying options, etc.)

    // for measure request time, it will add `X-Client-Time` header, then consume on response (error)
    CurlUtils.addXClientTime(options);

    CurlUtils.handleOnRequest(options);
    handler.next(options);
  }
  @override
  void onResponse(Response response, ResponseInterceptorHandler handler) {
    // ... your response handling logic
    CurlUtils.handleOnResponse(response);
    handler.next(response);
  }
  @override
  void onError(DioException err, ErrorInterceptorHandler handler) {
    // ... your error handling logic
    CurlUtils.handleOnError(err);
    handler.next(err);
  }
}

Option 3: Using utility functions directly

If you don't want to add a full interceptor, you can use the utility functions directly in your code:

// Generate a curl command from request options
final dio = Dio();
final response = await dio.get('https://example.com');

// Generate and log a curl command
CurlUtils.logCurl(response.requestOptions);

// Log response details
CurlUtils.handleOnResponse(response);

// Log error details
try {
  await dio.get('https://invalid-url.com');
} on DioException catch (e) {
  CurlUtils.handleOnError(e);
}

Option 4: Retrieve the curl

If you want to retrieve the curl command from a response, you can use the genCurl public function:

final curl = genCurl(requestOptions);

// now you can log, share, etc...

Dio Cache Storage

Public Flutter Widget: cURL Log Viewer

Show pre-built popup cURL log viewer widget with showCurlViewer(context):

ElevatedButton(
  onPressed: () => showCurlViewer(context),
  child: const Text('View cURL Logs'),
);

The log viewer supports:

• Search and filter by status code, date range, or text
• Export filtered logs to JSON
• Copy cURL command
• Clear all logs

Cache Storage Initialization

Before using caching or the log viewer, initialize storage in your main():

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await CachedCurlStorage.init();
  runApp(const MyApp());
}

License

This project is licensed under the MIT License - see the LICENSE file for details.

• Repository: GitHub
• Bug Reports: Please file issues on the GitHub repository
• Feature Requests: Feel free to suggest new features through GitHub issues

Contributions are welcome! Please feel free to submit a Pull Request.