RChecker

A high-performance asynchronous domain availability checker supporting pattern matching and wordlist modes with checkpoint/resume functionality.

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RChecker

A fast and efficient domain availability checking tool
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Project Overview

RChecker is a professional domain availability checking tool that uses asynchronous HTTP requests and the RDAP protocol to efficiently check the registration status of large numbers of domains. The tool supports multiple operation modes, including pattern matching generation, wordlist import, and checkpoint/resume functionality.

Key Features

• 🚀 High-Performance Async Checking: Concurrent domain queries using aiohttp
• 🎯 Multiple Generation Modes: Supports both pattern matching and wordlist domain generation
• 📊 Real-time Progress Display: Progress bar with detailed statistics
• 💾 Checkpoint/Resume: Resume from where you left off after interruption
• 🌐 Online Wordlists: Built-in download functionality for various online wordlist sources
• ⚡ Rate Limiting: Configurable request rate control
• 📝 Result Export: Automatically save available domains to file

Table of Contents

• Getting Started
  • Prerequisites
  • Installation
• Usage
  • Basic Usage
  • Advanced Options
  • Wordlist Mode
• File Structure
• Configuration Options
• Contributors
• Versioning
• License

Getting Started

Prerequisites

• Python 3.8 or higher
• Stable internet connection
• Sufficient disk space for storing results and progress files

Installation

Option 1: Install from PyPI (Recommended)

pip install rchecker

Option 2: Install from Source

1. Clone the repository

git clone https://github.com/Rain-kl/RChecker.git
cd RChecker

2. Install in development mode

pip install -e .

Or using uv (recommended):

uv sync

3. Run the tool

rchecker --help

Usage

Basic Usage

1. Pattern Matching Mode

Check domains starting with specific prefixes:

# Check all 3-character .com domains
rchecker "a*" --max 3 --tld com

# Check domains with specific prefix
rchecker "app*" --max 6 --min 4 --tld com

2. Exact Domain Check

# Check single domain
rchecker "example" --max 7 --min 7 --tld com

3. Wordlist Mode

# Use custom wordlist
rchecker --wordlist words.txt --max 10 --tld com

# Download and use online wordlist
rchecker download common-small
rchecker --wordlist google-10000-english-usa.txt --max 8 --tld com

Advanced Options

Performance Tuning

# Adjust concurrency and request rate
rchecker "test*" --max 5 --concurrency 20 --rate 100

# Set timeout and retry count
rchecker "app*" --max 6 --timeout 15 --retries 3

Checkpoint/Resume

# Enable checkpoint/resume functionality
rchecker "data*" --max 6 --resume --progress-file my_progress.json

# Randomize check order
rchecker "api*" --max 5 --shuffle

Custom Output

# Specify output file
rchecker "web*" --max 5 --output available_web_domains.txt

# Disable progress bar
rchecker "blog*" --max 6 --no-progress

Wordlist Mode

View Available Online Wordlists

rchecker download list

Download Wordlists

# Download common English words
rchecker download common-small

# Download to specific location
rchecker download names --output first_names.txt

# Force overwrite existing file
rchecker download adjectives --force

Built-in Wordlist Sources

Name	Description	Word Count
common	Common English words	370,000+
common-small	Most common English words	10,000
common-tiny	Most common English words (no profanity)	10,000
names	Common first names	5,000+
adjectives	English adjectives	1,300+

File Structure

RChecker/
├── rchecker/               # Main package directory
│   ├── __init__.py         # Package initialization
│   ├── main.py             # Core functionality
│   └── cli.py              # Command-line interface
├── pyproject.toml          # Project configuration
├── MANIFEST.in             # Package manifest
├── LICENSE.txt             # MIT License
├── README.md               # Project documentation (English)
├── README-CN.md            # Project documentation (Chinese)
├── README.en.md            # Project documentation (English)
├── README copy.md          # README template
├── uv.lock                 # Dependency lock file
├── __pycache__/           # Python cache directory
├── images/                # Image resources
│   └── logo.png           # Project logo
├── available_domains.txt   # Default output file (generated after run)
└── .dcheck_progress.json  # Progress file (generated with checkpoint)

Configuration Options

Command Line Arguments

Parameter	Type	Default	Description
pattern	String	-	Domain pattern (supports trailing wildcard *)
--tld	String	com	Top-level domain
--max	Integer	Required	Maximum domain length
--min	Integer	Equal to max	Minimum domain length
--rate	Float	50.0	Maximum requests per second (0 for unlimited)
--concurrency	Integer	15	Number of concurrent workers
--timeout	Float	10.0	HTTP request timeout (seconds)
--charset	String	a-z	Character set for wildcard expansion
--retries	Integer	2	Number of retries for failed requests
--output	String	available_domains.txt	Output file for results
--wordlist	String	-	Path to wordlist file
--resume	Boolean	False	Enable checkpoint/resume
--progress-file	String	.dcheck_progress.json	Progress file path
--shuffle	Boolean	False	Randomize check order
--no-progress	Boolean	False	Disable progress bar

Performance Recommendations

• Concurrency: 15-30 concurrent workers are suitable for most network environments
• Request Rate: Recommend 10-100 requests/second to avoid being rate-limited
• Timeout: Increase to 15-30 seconds for slower networks
• Retries: Increase to 3-5 for unstable networks

Technical Architecture

Core Components

1. Asynchronous Network Layer: High-concurrency HTTP requests based on aiohttp
2. RDAP Protocol: Uses standard RDAP interface to query domain registration information
3. Progress Management: Implements checkpoint/resume and real-time progress display
4. Rate Control: Prevents requests from being too fast and getting server-limited
5. Result Processing: Automatic classification and saving of check results

Workflow

graph TD
    A[Parse Command Arguments] --> B{Choose Mode}
    B -->|Pattern Match| C[Generate Domain List]
    B -->|Wordlist| D[Load Wordlist File]
    C --> E[Initialize Async Session]
    D --> E
    E --> F[Create Worker Pool]
    F --> G[Concurrent Domain Check]
    G --> H[RDAP Query]
    H --> I{Domain Status}
    I -->|404| J[Mark as Available]
    I -->|200| K[Mark as Registered]
    I -->|Error| L[Mark as Error]
    J --> M[Save to File]
    K --> N[Update Statistics]
    L --> N
    M --> O[Show Progress]
    N --> O
    O --> P{More Domains?}
    P -->|Yes| G
    P -->|No| Q[Complete and Cleanup]

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Contributors

Thanks to all developers who have contributed to this project!

How to Contribute

1. Fork the project
2. Create your feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

Versioning

This project uses SemVer for versioning. For available versions, see the Releases.

Changelog

• v0.1.0 - Initial release
  • Basic domain checking functionality
  • Pattern matching and wordlist support
  • Asynchronous concurrent processing
  • Checkpoint/resume functionality

License

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

FAQ

Q: Why do some domain checks fail?

A: Possible reasons include network timeouts, temporary RDAP server unavailability, or non-compliant domain formats. The tool will automatically retry failed requests.

Q: How to improve checking speed?

A: You can appropriately increase the --concurrency and --rate parameter values, but be careful not to set them too high to avoid being server-limited.

Q: Which top-level domains are supported?

A: Supports all top-level domains registered in the RDAP system, including .com, .net, .org, .cn, etc.

Q: What is the result file format?

A: The output file is in plain text format, one available domain per line, convenient for further processing.

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