Best practices for regular expressions versus Regex performance review

[EngRajabi]

Proposed changes

Regex improvements:

• set option compile
• set timeout
• set static object (Regex class is immutable)

Links

• Microsoft Docs: Best Practices for Regular Expressions in .NET | Microsoft Learn
• .NET Blog: Regular Expression Improvements in .NET 7

[Hossein-Edraki]

It's Ok

[EngRajabi]

@TomPallister

[WeihanLi]

What if timeout happens? Timeout maybe not good practice here.

[EngRajabi]

Setting timeout is one of the necessary tasks of using regex. When a timeout occurs, it is best to run the entire project involved and not respond to others.

[WeihanLi]

Is there some reason for considering 100ms as the regex timeout, and how could the client update the timeout config if the client wanna use a longer timeout?

[EngRajabi]

timeout is not customizable by the customer. Like many other settings. It was 100 ms when I adjusted it according to the tests I had. But we can decide here and change this time. We can set this time to 500 ms. If we do not receive an answer at this time, it is better not to involve the whole project in its implementation and let it respond to other requests.

[EngRajabi]

review done

[raman-m]

Dear Mohsen,

Why did you merge develop branch from your fork into the feature branch?
I meant these commits: ff1dbb6 5b336cd
It was unnecessary because I did the merge of ThreeMammals:develop in 329d2c3.
After that I trigger pipeline to make a valid green build for commit 03a70b3.

Now there is no build at all and pipeline cannot run new build.
The pipeline cannot recognize develop branch because you have juggled all commits in a wrong way.

Could you fix/update your fork develop branch please first?

After that we will try to fix pipeline triggering by rebasing current feature branch onto develop one.

[EngRajabi]

I did Branch Develop on Branch as Rebase. Does this solve this problem?

[raman-m]

Now I see develop and it has zero diff, but the branch is not default. ☝️
You have to go to repo settings and make develop branch as default!
I hope that should help to fix the problem of builds, because all builds are built for develop branch (auto) and master (manually).
Currently I don't see that pipeline was triggered for top commit.
Maybe an empty or tiny commit will be required to trigger the pipeline after making develop branch default.

[EngRajabi]

change something for build

[raman-m]

Feature branch has been rebased onto develop!
The build has been passed for top commit!

Going to start code review...

I guess, this PR is not related to an issue, right?

[raman-m]

Ready for Final Code Review❕

The following items need verification:

• Define the TimeSpan.FromMilliseconds(100) parameter as a global static property to allow advanced configuration of this constant in C#. → Docs: Use time-out values
• Convert all Regex definitions to GeneratedRegex, following best practices in .NET 7+. See the Ocelot.DependencyInjection.ConfigurationBuilderExtensions class for an example, particularly the SubConfigRegex() method →
  

  Ocelot/src/Ocelot/DependencyInjection/ConfigurationBuilderExtensions.cs

  Lines 18 to 24 in d310508

  	#if NET7_0_OR_GREATER
  	[GeneratedRegex(@"^ocelot\.(.*?)\.json$", RegexOptions.IgnoreCase | RegexOptions.Singleline, "en-US")]
  	private static partial Regex SubConfigRegex();
  	#else
  	private static readonly Regex SubConfigRegexVar = new(@"^ocelot\.(.*?)\.json$", RegexOptions.IgnoreCase | RegexOptions.Singleline, TimeSpan.FromMilliseconds(1000));
  	private static Regex SubConfigRegex() => SubConfigRegexVar;
  	#endif

  
  The preprocessor if-directive is necessary to accommodate support for net6.0, as well as for net7.0 and net8.0
• Ensure that all Regex expressions are converted throughout the entire solution.

[raman-m]

@EngRajabi Hello, Mohsen! Are you energized and ready to deliver this PR? 😄

[raman-m]

Ready for Delivery ✅

[ggnaegi]

@raman @RaynaldM Again, I would have prefered moving to .NET 7-9 before to reduce the complexity and ensure a better maintainability.