Add proxy support

CHANGELOG.md

@@ -17,6 +17,27 @@
     appRunner: () => runApp(MyApp()),
   );
   ```
+- Add proxy support ([#2192](https://github.com/getsentry/sentry-dart/pull/2192))
+  - Configure a `SentryProxy` object and set it on `SentryFlutter.init`
+  ```dart
+  import 'package:flutter/widgets.dart';
+  import 'package:sentry_flutter/sentry_flutter.dart';
+
+  Future<void> main() async {
+    await SentryFlutter.init(
+      (options) {
+        options.dsn = 'https://[email protected]/add-your-dsn-here';
+        options.proxy = SentryProxy(
+          type: SenryProxyType.http,
+          host: 'localhost',
+          port: 8080,
+        );
+      },
+      // Init your App.
+      appRunner: () => runApp(MyApp()),
+    );
+  }
+  ```
 
 ### Improvements
 
@@ -72,7 +93,7 @@ SentryFlutter.init((options) =>
   - This allows viewing the correct dart formatted raw stacktrace in the Sentry UI
 - Support `ignoredExceptionsForType` ([#2150](https://github.com/getsentry/sentry-dart/pull/2150))
   - Filter out exception types by calling `SentryOptions.addExceptionFilterForType(Type exceptionType)`
-  
+
 ### Fixes
 
 - Disable sff & frame delay detection on web, linux and windows ([#2182](https://github.com/getsentry/sentry-dart/pull/2182))

dart/lib/sentry.dart

@@ -56,3 +56,5 @@ export 'src/sentry_span_operations.dart';
 export 'src/utils.dart';
 // spotlight debugging
 export 'src/spotlight.dart';
+// proxy
+export 'src/protocol/sentry_proxy.dart';

dart/lib/src/http_client/client_provider.dart

@@ -0,0 +1,16 @@
+import 'package:meta/meta.dart';
+import 'package:http/http.dart';
+
+import '../sentry_options.dart';
+
+@internal
+ClientProvider getClientProvider() {
+  return ClientProvider();
+}
+
+@internal
+class ClientProvider {
+  Client getClient(SentryOptions options) {
+    return Client();
+  }
+}

dart/lib/src/http_client/io_client_provider.dart

@@ -0,0 +1,67 @@
+import 'dart:io';
+
+import 'package:http/http.dart';
+import 'package:http/io_client.dart';
+import 'package:meta/meta.dart';
+
+import '../protocol.dart';
+import '../protocol/sentry_proxy.dart';
+import '../sentry_options.dart';
+import 'client_provider.dart';
+
+@internal
+ClientProvider getClientProvider() {
+  return IoClientProvider(
+    () {
+      return HttpClient();
+    },
+    (user, pass) {
+      return HttpClientBasicCredentials(user, pass);
+    },
+  );
+}
+
+@internal
+class IoClientProvider implements ClientProvider {
+  final HttpClient Function() _httpClient;
+  final HttpClientCredentials Function(String, String) _httpClientCredentials;
+
+  IoClientProvider(this._httpClient, this._httpClientCredentials);
+
+  @override
+  Client getClient(SentryOptions options) {
+    final proxy = options.proxy;
+    if (proxy == null) {
+      return Client();
+    }
+    final pac = proxy.toPacString();
+    if (proxy.type == SentryProxyType.socks) {
+      options.logger(
+        SentryLevel.warning,
+        "Setting proxy '$pac' is not supported.",
+      );
+      return Client();
+    }
+    options.logger(
+      SentryLevel.info,
+      "Setting proxy '$pac'",
+    );
+    final httpClient = _httpClient();
+    httpClient.findProxy = (url) => pac;
+
+    final host = proxy.host;
+    final port = proxy.port;
+    final user = proxy.user;
+    final pass = proxy.pass;
+
+    if (host != null && port != null && user != null && pass != null) {
+      httpClient.addProxyCredentials(
+        host,
+        port,
+        '',
+        _httpClientCredentials(user, pass),
+      );
+    }
+    return IOClient(httpClient);
+  }
+}

dart/lib/src/protocol/sentry_proxy.dart

@@ -0,0 +1,62 @@
+class SentryProxy {
+  final SentryProxyType type;
+  final String? host;
+  final int? port;
+  final String? user;
+  final String? pass;
+
+  SentryProxy({required this.type, this.host, this.port, this.user, this.pass});
+
+  String toPacString() {
+    String type = 'DIRECT';
+    switch (this.type) {
+      case SentryProxyType.direct:
+        return 'DIRECT';
+      case SentryProxyType.http:
+        type = 'PROXY';
+        break;
+      case SentryProxyType.socks:
+        type = 'SOCKS';
+        break;
+    }
+    if (host != null && port != null) {
+      return '$type $host:$port';
+    } else if (host != null) {
+      return '$type $host';
+    } else {
+      return 'DIRECT';
+    }
+  }
+
+  /// Produces a [Map] that can be serialized to JSON.
+  Map<String, dynamic> toJson() {
+    return {
+      if (host != null) 'host': host,
+      if (port != null) 'port': port,
+      'type': type.toString().split('.').last.toUpperCase(),
+      if (user != null) 'user': user,
+      if (pass != null) 'pass': pass,
+    };
+  }
+
+  SentryProxy copyWith({
+    String? host,
+    int? port,
+    SentryProxyType? type,
+    String? user,
+    String? pass,
+  }) =>
+      SentryProxy(
+        host: host ?? this.host,
+        port: port ?? this.port,
+        type: type ?? this.type,
+        user: user ?? this.user,
+        pass: pass ?? this.pass,
+      );
+}
+
+enum SentryProxyType {
+  direct,
+  http,
+  socks;
+}

dart/lib/src/sentry_options.dart

@@ -496,6 +496,19 @@ class SentryOptions {
   /// ```
   Spotlight spotlight = Spotlight(enabled: false);
 
+  /// Configure a proxy to use for SDK API calls.
+  ///
+  /// On io platforms without native SDKs (dart, linux, windows), this will use
+  /// an 'IOClient' with inner 'HTTPClient' for http communication.
+  /// A http proxy will be set in returned for 'HttpClient.findProxy' in the
+  /// form 'PROXY <your_host>:<your_port>'.
+  /// When setting 'user' and 'pass', the 'HttpClient.addProxyCredentials'
+  /// method will be called with empty 'realm'.
+  ///
+  /// On Android & iOS, the proxy settings are handled by the native SDK.
+  /// iOS only supports http proxies, while macOS also supports socks.
+  SentryProxy? proxy;
+
   SentryOptions({this.dsn, PlatformChecker? checker}) {
     if (checker != null) {
       platformChecker = checker;

dart/lib/src/transport/http_transport.dart

@@ -11,6 +11,8 @@ import '../sentry_options.dart';
 import '../sentry_envelope.dart';
 import 'transport.dart';
 import 'rate_limiter.dart';
+import '../http_client/client_provider.dart'
+    if (dart.library.io) '../http_client/io_client_provider.dart';
 
 /// A transport is in charge of sending the event to the Sentry server.
 class HttpTransport implements Transport {
@@ -22,9 +24,8 @@ class HttpTransport implements Transport {
 
   factory HttpTransport(SentryOptions options, RateLimiter rateLimiter) {
     if (options.httpClient is NoOpClient) {
-      options.httpClient = Client();
+      options.httpClient = getClientProvider().getClient(options);
     }
-
     return HttpTransport._(options, rateLimiter);
   }
 

dart/lib/src/transport/spotlight_http_transport.dart

@@ -4,6 +4,8 @@ import 'http_transport_request_handler.dart';
 
 import '../../sentry.dart';
 import '../noop_client.dart';
+import '../http_client/client_provider.dart'
+    if (dart.library.io) '../http_client/io_client_provider.dart';
 
 /// Spotlight HTTP transport decorator that sends Sentry envelopes to both Sentry and Spotlight.
 class SpotlightHttpTransport extends Transport {
@@ -13,7 +15,7 @@ class SpotlightHttpTransport extends Transport {
 
   factory SpotlightHttpTransport(SentryOptions options, Transport transport) {
     if (options.httpClient is NoOpClient) {
-      options.httpClient = Client();
+      options.httpClient = getClientProvider().getClient(options);
     }
     return SpotlightHttpTransport._(options, transport);
   }