Log forwarder

Author: alwx

packages/core/ios/RNSentryNativeLogsForwarder.h

@@ -0,0 +1,33 @@
+#import <Foundation/Foundation.h>
+#import <React/RCTEventEmitter.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+/**
+ * Singleton class that forwards native Sentry SDK logs to JavaScript via React Native events.
+ * This allows React Native developers to see native SDK logs in the Metro console.
+ */
+@interface RNSentryNativeLogsForwarder : NSObject
+
+/**
+ * Returns the shared instance of the logs forwarder.
+ */
++ (instancetype)shared;
+
+/**
+ * Configures the forwarder with the event emitter to use for sending events to JS.
+ * Call this when the React Native module starts observing events.
+ *
+ * @param emitter The RCTEventEmitter instance (typically the RNSentry module).
+ */
+- (void)configureWithEventEmitter:(RCTEventEmitter *)emitter;
+
+/**
+ * Clears the event emitter reference.
+ * Call this when the React Native module stops observing events.
+ */
+- (void)stopForwarding;
+
+@end
+
+NS_ASSUME_NONNULL_END

packages/core/ios/RNSentryNativeLogsForwarder.m

@@ -0,0 +1,128 @@
+#import "RNSentryNativeLogsForwarder.h"
+
+@import Sentry;
+
+static NSString *const RNSentryNativeLogEventName = @"SentryNativeLog";
+
+@interface RNSentryNativeLogsForwarder ()
+
+@property (nonatomic, weak) RCTEventEmitter *eventEmitter;
+
+@end
+
+@implementation RNSentryNativeLogsForwarder
+
++ (instancetype)shared
+{
+    static RNSentryNativeLogsForwarder *instance = nil;
+    static dispatch_once_t onceToken;
+    dispatch_once(&onceToken, ^{ instance = [[RNSentryNativeLogsForwarder alloc] init]; });
+    return instance;
+}
+
+- (void)configureWithEventEmitter:(RCTEventEmitter *)emitter
+{
+    self.eventEmitter = emitter;
+
+    __weak RNSentryNativeLogsForwarder *weakSelf = self;
+
+    // Set up the Sentry SDK log output to forward logs to JS
+    [SentrySDKLog setOutput:^(NSString *_Nonnull message) {
+        // Always print to console (default behavior)
+        NSLog(@"%@", message);
+
+        // Forward to JS if we have an emitter
+        RNSentryNativeLogsForwarder *strongSelf = weakSelf;
+        if (strongSelf) {
+            [strongSelf forwardLogMessage:message];
+        }
+    }];
+}
+
+- (void)stopForwarding
+{
+    self.eventEmitter = nil;
+
+    // Reset to default print behavior
+    [SentrySDKLog setOutput:^(NSString *_Nonnull message) { NSLog(@"%@", message); }];
+}
+
+- (void)forwardLogMessage:(NSString *)message
+{
+    RCTEventEmitter *emitter = self.eventEmitter;
+    if (emitter == nil) {
+        return;
+    }
+
+    // Parse the log message to extract level and component
+    // Format: "[Sentry] [level] [timestamp] [Component:line] message"
+    // or: "[Sentry] [level] [timestamp] message"
+    NSString *level = [self extractLevelFromMessage:message];
+    NSString *component = [self extractComponentFromMessage:message];
+    NSString *cleanMessage = [self extractCleanMessageFromMessage:message];
+
+    NSDictionary *body = @{
+        @"level" : level,
+        @"component" : component,
+        @"message" : cleanMessage,
+    };
+
+    [emitter sendEventWithName:RNSentryNativeLogEventName body:body];
+}
+
+- (NSString *)extractLevelFromMessage:(NSString *)message
+{
+    // Look for patterns like [debug], [info], [warning], [error], [fatal]
+    NSRegularExpression *regex =
+        [NSRegularExpression regularExpressionWithPattern:@"\\[(debug|info|warning|error|fatal)\\]"
+                                                  options:NSRegularExpressionCaseInsensitive
+                                                    error:nil];
+
+    NSTextCheckingResult *match = [regex firstMatchInString:message
+                                                    options:0
+                                                      range:NSMakeRange(0, message.length)];
+
+    if (match && match.numberOfRanges > 1) {
+        return [[message substringWithRange:[match rangeAtIndex:1]] lowercaseString];
+    }
+
+    return @"info";
+}
+
+- (NSString *)extractComponentFromMessage:(NSString *)message
+{
+    // Look for pattern like [ComponentName:123]
+    NSRegularExpression *regex =
+        [NSRegularExpression regularExpressionWithPattern:@"\\[([A-Za-z]+):\\d+\\]"
+                                                  options:0
+                                                    error:nil];
+
+    NSTextCheckingResult *match = [regex firstMatchInString:message
+                                                    options:0
+                                                      range:NSMakeRange(0, message.length)];
+
+    if (match && match.numberOfRanges > 1) {
+        return [message substringWithRange:[match rangeAtIndex:1]];
+    }
+
+    return @"Sentry";
+}
+
+- (NSString *)extractCleanMessageFromMessage:(NSString *)message
+{
+    // Remove the prefix parts: [Sentry] [level] [timestamp] [Component:line]
+    // and return just the actual message content
+    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:
+            @"^\\[Sentry\\]\\s*\\[[^\\]]+\\]\\s*\\[[^\\]]+\\]\\s*(?:\\[[^\\]]+\\]\\s*)?"
+                                                                           options:0
+                                                                             error:nil];
+
+    NSString *cleanMessage = [regex stringByReplacingMatchesInString:message
+                                                             options:0
+                                                               range:NSMakeRange(0, message.length)
+                                                        withTemplate:@""];
+
+    return [cleanMessage stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
+}
+
+@end