Log Rule

Automatically injects JavaScript code into pages to capture JavaScript exceptions and console.xxx logs, displaying them in real-time on the Whistle management interface.

Overview

• Exception Monitoring: Automatically captures JavaScript execution errors and unhandled Promise rejections in pages.
• Log Collection: Intercepts and collects all console outputs such as console.log(), console.warn(), and console.error().
• Visual Log Viewing: View, filter, and search logs by group in real-time within the Whistle management interface.
• Log Preprocessing: Supports filtering or formatting log content through custom scripts.

Rule Syntax

pattern log://id [filters...]

Parameter Description

Parameter	Required	Description	Details
pattern	Yes	Expression matching request URLs to specify pages to monitor	Pattern Matching Syntax
id	Yes	Log group identifier (plain string) to distinguish and filter logs from different sources in the Whistle interface	Logs within the same group are displayed together, supporting quick view switching by ID
filters	No	Filter conditions to further match specific characteristics of requests or responses	Filter Syntax Supports filtering by URL, method, request headers, response status codes, etc.

Usage

Basic Usage

Capture logs from all pages under a specified domain:

www.example.com log://myapp

Multi-Domain Group Monitoring

Set different log groups for different domains or paths for categorized viewing:

ke.qq.com log://ke
news.qq.com log://news
api.example.com log://api

Advanced Configuration: Log Preprocessing

Inject custom scripts via the jsPrepend rule to preprocess logs before they are sent to Whistle, such as sensitive information masking, format conversion, or conditional filtering.

Configuration Example

www.example.com log:// jsPrepend://{handleLog.js}

Preprocessing Script Example

// handleLog.js
// Custom processing function executed before logs are sent to Whistle
window.onBeforeWhistleLogSend = function(result, level) {
  // result: Array of raw messages to be output
  // level: Log level ('log', 'warn', 'error', 'info', 'debug')
  
  result.forEach(function(msg, i) {
    // Example 1: Hide sensitive keywords
    if (typeof msg === 'string' && msg.includes('password')) {
      result[i] = '[SENSITIVE DATA HIDDEN]';
    }
    
    // Example 2: Convert specific content to structured objects
    if (msg === 'abc') {
      result[i] = {
        name: 'avenwu',
        level: level,
        timestamp: new Date().toISOString()
      };
    }
    
    // Example 3: Filter out certain types of logs
    if (msg === 'ignore-this-message') {
      // Returning an empty array will prevent this log from being sent
      result.splice(i, 1);
    }
  });
};

Interface Operation Guide

Viewing Logs

1. Open the Whistle management interface (default: http://127.0.0.1:8899)
2. Switch to the Network / Tools / Console tab
3. Select the corresponding log group ID in the top-left corner
4. View page output logs and error information in real-time

Log Filtering

• Use the top filter bar to quickly filter by log level (Log/Warn/Error)
• Supports keyword search to quickly locate specific logs