GuardRegex 1.0.0

GuardRegex

Overview

GuardRegex is a wrapper utility for .NET Regex.

It performs lightweight input validation and enforces a timeout setting when invoking .NET Regex.

• Regex metacharacter escaping support
• Null input validation
• Excessively long input validation
• Prevention of executions without an explicit timeout

GuardRegex relies on the error handling provided by .NET Regex and transparently propagates exceptions raised by .NET Regex.

Intended Audience

Developers who use .NET Regex on a regular basis.

Features

RegexEscaper

An extended escaper/unescaper for System.Text.RegularExpressions.Regex.Escape and Unescape.

Features:

• Conservatively escapes and unescapes a broad set of special symbols used in .NET Regex syntax
• Restores escaped strings through unescaping
• Unescape(Escape(x)) == x
• Escape(Unescape(x)) != x

Example:

string escaped = RegexEscaper.Escape("(sample)");
Console.WriteLine(escaped);

string restored = RegexEscaper.Unescape(escaped);
Console.WriteLine(restored);

GuardRegex

A protective wrapper around the invocation boundary of System.Text.RegularExpressions.Regex.

Features:

• Null validation
• Maximum input length validation
• Default timeout enforcement
• Regex API wrapping

Example:

var regex = new GuardRegex(@"\d+", timeout: TimeSpan.FromSeconds(2));
bool matched = regex.IsMatch("123");

Exceptions and Responsibility Boundaries

GuardRegex does not replace the regular expression engine.

The following behaviors are delegated to System.Text.RegularExpressions.Regex:

• Regular expression syntax errors
• Regular expression engine behavior
• Matching algorithms
• Exceptions raised due to timeout
• Behaviors dependent on the .NET Runtime Regex implementation

Design Principles

GuardRegex emphasizes the Single Responsibility Principle.

• RegexEscaper is responsible for string transformation.
• GuardRegex is responsible for protecting the Regex invocation boundary.

Features beyond these responsibilities are intentionally excluded.

License

• This project is distributed under the MIT License.

Disclaimer

• This software is provided as-is, and all responsibility for its use belongs to the user.
• The developer's employer, affiliation, or contractual status does not affect the terms of use or responsibilities associated with this software.

Contribution Policy

• This project is primarily intended for personal technical research and publication. At present, external contributions via Issues or Pull Requests are not accepted. Thank you for your understanding.
• Bug reports related to implemented functionality are welcome.

Author

• Rikou Natsuki (夏木 梨好)
• GitHub: RikouNatsuki
• For inquiries, please use Issues