FilterPipelines

FilterPipelines は middleware pattern によってフィルター パイプラインを構築する為の、シンプルな .NET ヘルパーライブラリです。

Target Frameworks

• .NET Standard 2.0+
• .NET Standard 1.0+
• .NET Framework 4.5+

Usage

MiddlewareFunc delegate

Func<Uri, Task<PredicateFunc<FileInfo>>> pipeline = FilterPipeline.Build(new MiddlewareFunc<Uri, Task<PredicateFunc<FileInfo>>>[]{
    next => async context => {
        if (!context.Scheme.Equals("https", StringComparison.OrdinalIgnoreCase)) { return _ => false; }
        return await next(context);
    },
    next => async context => {
        var nextPredicate = await next(context);
        var uriPath = context.AbsolutePath.TrimStart('/');
        return file => Path.GetFileNameWithoutExtension(file.Name).Equals(uriPath, StringComparison.OrdinalIgnoreCase) && nextPredicate(file);
    },
});

var predicate = await pipeline(new Uri("https://example.com/foo"));
Assert.AreEqual(true, predicate(new FileInfo("foo.html")));
Assert.AreEqual(false, predicate(new FileInfo("bar.html")));

Assert.AreEqual(false, (await pipeline(new Uri("http://example.com/foo")))(new FileInfo("foo.html")));

IMiddleware interface

public async Task Main() {
    var middlewares = new PredicateMiddleware<Uri, FileInfo>[]{
        new HttpsPredicate(),
        new StaticFilePredicate(),
    };
    Func<Uri, Task<PredicateFunc<FileInfo>>> pipeline = FilterPipeline.Build(middlewares.Select(x => x.ToDelegate()));

    var predicate = await pipeline(new Uri("https://example.com/foo"));
    Assert.AreEqual(true, predicate(new FileInfo("foo.html")));
    Assert.AreEqual(false, predicate(new FileInfo("bar.html")));

    Assert.AreEqual(false, (await pipeline(new Uri("http://example.com/foo")))(new FileInfo("foo.html")));
}

public class HttpsPredicate : PredicateMiddleware<Uri, FileInfo> {

    protected override async Task<PredicateFunc<FileInfo>> CreateAsync(Uri context, Func<Uri, Task<PredicateFunc<FileInfo>>> next) {
        if (!context.Scheme.Equals("https", StringComparison.OrdinalIgnoreCase)) { return _ => false; }
        return await next(context);
    }
}

public class StaticFilePredicate : PredicateMiddleware<Uri, FileInfo> {

    protected override PredicateFunc<FileInfo> Create(Uri context, ref bool cancelled) {
        var uriPath = context.AbsolutePath.TrimStart('/');
        return file => Path.GetFileNameWithoutExtension(file.Name).Equals(uriPath, StringComparison.OrdinalIgnoreCase);
    }
}

Licence

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