SafeRateLimiter

A Python project that implements a Rate Limiter decorator to restrict function calls within a specified time window. This helps prevent excessive calls and protects system resources.

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Description

RateLimiterPy uses Python decorators to monitor and control how many times a function can be called within a given time frame. By storing timestamps of recent calls in a local list (closure), the decorator allows a function to run only if the number of calls in the defined period is below a specified limit. If the limit is exceeded, a ValueError is raised.

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Features

• Function Call Control: Limit the number of function executions per time period.
• High-Resolution Timing: Uses time.perf_counter() for precise measurement.
• Closure-Based Storage: Keeps call timestamps local to each decorated function.
• Simple and Extensible: Easy to apply to any function requiring rate limiting.

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Installation

1. Clone the repository:

   git clone https://github.com/YourUsername/RateLimiterPy.git
   cd RateLimiterPy

2. (Optional) Create a virtual environment and install dependencies:

   python -m venv env
   source env/bin/activate  # On Windows use: env\Scripts\activate
   pip install -r requirements.txt

   Note: This project uses only standard libraries (e.g., time, functools), so no additional packages are required.

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Usage

Apply the rate limiter decorator to your function by specifying the maximum number of allowed calls and the time window (in seconds).

Example:

import time
from Rate_Limiter import Rate_limiter

@Rate_limiter(3, 5)
def say_hello(name):
    return f"Hello to {name}"

if __name__ == "__main__":
    # This loop will raise a ValueError once the rate limit is exceeded
    for _ in range(10):
        try:
            print(say_hello("sara"))
        except ValueError as e:
            print(e)
    
    time.sleep(5)  # Wait for the rate limiter to reset
    print(say_hello("ali"))

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Testing

Tests are written using pytest to verify the behavior under various conditions including valid calls, invalid (exceeding) calls, and edge cases.

Run Tests:

1. Ensure you have pytest installed:

   pip install pytest

2. Run the tests:

   pytest

Example Test Cases:

• Valid Calls: Confirm that functions return correct values when calls are within limits.
• Invalid Calls: Verify that a ValueError is raised when the rate limit is exceeded.
• Edge Cases: Test boundary conditions with appropriate use of time.sleep() to reset the limiter.

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Contributing

Contributions are welcome! If you have suggestions or improvements:

• Fork the repository.
• Create a feature branch.
• Commit your changes and open a pull request.

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License

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

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Contact

For any questions or issues, please open an issue on GitHub or contact Parisa Alizadeh.

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