UriHelper.BuildRelative: opportunity for performance improvement

[paulomorgado]

Summary

UriHelper.BuildRelative creates an intermediary string for the combined path that is used only for concatenating with the other components to create the final URL.

public static string BuildRelative(
    PathString pathBase = new PathString(),
    PathString path = new PathString(),
    QueryString query = new QueryString(),
    FragmentString fragment = new FragmentString())
{
    string combinePath = (pathBase.HasValue || path.HasValue) ? (pathBase + path).ToString() : "/";
    return combinePath + query.ToString() + fragment.ToString();
}

Motivation and goals

This method is frequently use in hot paths like redirect and rewrite rules.

Detailed design

Single_Concat

Given that the final URL is composed of only 3 or 4 parts, the use of string.Concat is both time and memory efficient.

String_Create

string.Create could be used. But it's just as memory efficient as string.Concat and less time efficient is most cases.

Benchmarks

BenchmarkDotNet=v0.12.1, OS=Windows 10.0.21277
Intel Core i7-8650U CPU 1.90GHz (Kaby Lake R), 1 CPU, 8 logical and 4 physical cores
.NET Core SDK=5.0.200-preview.20614.14
  [Host]     : .NET Core 5.0.1 (CoreCLR 5.0.120.57516, CoreFX 5.0.120.57516), X64 RyuJIT
  DefaultJob : .NET Core 5.0.1 (CoreCLR 5.0.120.57516, CoreFX 5.0.120.57516), X64 RyuJIT

Method	pathBase	path	query	fragment	Mean	Error	StdDev	Median	Ratio	RatioSD	Gen 0	Gen 1	Gen 2	Allocated
UriHelper_BuildRelative					10.334 ns	0.3064 ns	0.4948 ns	10.278 ns	1.00	0.00	-	-	-	-
Single_Concat					7.557 ns	0.1385 ns	0.1295 ns	7.534 ns	0.71	0.04	-	-	-	-
String_Create					8.398 ns	0.2614 ns	0.4646 ns	8.210 ns	0.82	0.07	-	-	-	-
UriHelper_BuildRelative				#fragment	29.557 ns	0.5777 ns	0.8098 ns	29.433 ns	1.00	0.00	0.0114	-	-	48 B
Single_Concat				#fragment	25.987 ns	0.5162 ns	0.4576 ns	25.986 ns	0.87	0.04	0.0114	-	-	48 B
String_Create				#fragment	37.347 ns	0.7226 ns	0.9395 ns	37.080 ns	1.26	0.04	0.0114	-	-	48 B
UriHelper_BuildRelative			?param1=value1&param2=value2&param3=value3		99.900 ns	1.4810 ns	1.2367 ns	99.743 ns	1.00	0.00	0.0267	-	-	112 B
Single_Concat			?param1=value1&param2=value2&param3=value3		100.739 ns	2.1000 ns	3.4504 ns	99.189 ns	1.01	0.04	0.0267	-	-	112 B
String_Create			?param1=value1&param2=value2&param3=value3		108.600 ns	1.1783 ns	1.0445 ns	108.788 ns	1.09	0.02	0.0267	-	-	112 B
UriHelper_BuildRelative			?param1=value1&param2=value2&param3=value3	#fragment	103.621 ns	1.6522 ns	1.9668 ns	103.039 ns	1.00	0.00	0.0305	-	-	128 B
Single_Concat			?param1=value1&param2=value2&param3=value3	#fragment	103.340 ns	2.1289 ns	2.7682 ns	102.687 ns	1.00	0.03	0.0305	-	-	128 B
String_Create			?param1=value1&param2=value2&param3=value3	#fragment	114.593 ns	2.3370 ns	2.2953 ns	114.116 ns	1.10	0.03	0.0305	-	-	128 B
UriHelper_BuildRelative		/path/one/two/three			145.257 ns	2.9859 ns	2.9325 ns	144.811 ns	1.00	0.00	-	-	-	-
Single_Concat		/path/one/two/three			139.083 ns	2.5119 ns	2.2268 ns	139.028 ns	0.96	0.02	-	-	-	-
String_Create		/path/one/two/three			139.504 ns	2.0265 ns	1.8956 ns	139.482 ns	0.96	0.03	-	-	-	-
UriHelper_BuildRelative		/path/one/two/three		#fragment	185.283 ns	3.7939 ns	4.5163 ns	184.090 ns	1.00	0.00	0.0191	-	-	80 B
Single_Concat		/path/one/two/three		#fragment	172.680 ns	2.7930 ns	2.8682 ns	171.917 ns	0.93	0.03	0.0191	-	-	80 B
String_Create		/path/one/two/three		#fragment	181.909 ns	1.8544 ns	1.6439 ns	181.797 ns	0.98	0.03	0.0191	-	-	80 B
UriHelper_BuildRelative		/path/one/two/three	?param1=value1&param2=value2&param3=value3		246.532 ns	4.9295 ns	5.2746 ns	245.078 ns	1.00	0.00	0.0343	-	-	144 B
Single_Concat		/path/one/two/three	?param1=value1&param2=value2&param3=value3		236.133 ns	2.2584 ns	1.8859 ns	236.346 ns	0.96	0.02	0.0343	-	-	144 B
String_Create		/path/one/two/three	?param1=value1&param2=value2&param3=value3		256.853 ns	3.0590 ns	2.5544 ns	256.886 ns	1.04	0.02	0.0343	-	-	144 B
UriHelper_BuildRelative		/path/one/two/three	?param1=value1&param2=value2&param3=value3	#fragment	250.724 ns	4.9369 ns	4.8486 ns	250.070 ns	1.00	0.00	0.0401	-	-	168 B
Single_Concat		/path/one/two/three	?param1=value1&param2=value2&param3=value3	#fragment	246.514 ns	4.1097 ns	5.4863 ns	244.180 ns	0.99	0.03	0.0401	-	-	168 B
String_Create		/path/one/two/three	?param1=value1&param2=value2&param3=value3	#fragment	262.577 ns	4.2791 ns	4.0026 ns	261.847 ns	1.05	0.03	0.0401	-	-	168 B
UriHelper_BuildRelative	/base-path				78.592 ns	1.3297 ns	1.4780 ns	78.622 ns	1.00	0.00	-	-	-	-
Single_Concat	/base-path				76.572 ns	1.6192 ns	2.4236 ns	75.729 ns	0.98	0.04	-	-	-	-
String_Create	/base-path				78.741 ns	1.2896 ns	1.1432 ns	78.702 ns	1.00	0.03	-	-	-	-
UriHelper_BuildRelative	/base-path			#fragment	109.622 ns	1.8629 ns	1.7426 ns	109.826 ns	1.00	0.00	0.0153	-	-	64 B
Single_Concat	/base-path			#fragment	95.689 ns	1.2692 ns	1.1872 ns	95.927 ns	0.87	0.02	0.0153	-	-	64 B
String_Create	/base-path			#fragment	104.016 ns	0.7687 ns	0.6814 ns	104.075 ns	0.95	0.02	0.0153	-	-	64 B
UriHelper_BuildRelative	/base-path		?param1=value1&param2=value2&param3=value3		181.487 ns	3.3279 ns	4.7728 ns	180.207 ns	1.00	0.00	0.0305	-	-	128 B
Single_Concat	/base-path		?param1=value1&param2=value2&param3=value3		169.635 ns	3.2086 ns	3.8196 ns	168.079 ns	0.93	0.04	0.0305	-	-	128 B
String_Create	/base-path		?param1=value1&param2=value2&param3=value3		180.100 ns	2.3870 ns	1.9932 ns	179.820 ns	0.98	0.04	0.0305	-	-	128 B
UriHelper_BuildRelative	/base-path		?param1=value1&param2=value2&param3=value3	#fragment	185.033 ns	3.4618 ns	4.2513 ns	184.494 ns	1.00	0.00	0.0343	-	-	144 B
Single_Concat	/base-path		?param1=value1&param2=value2&param3=value3	#fragment	178.615 ns	3.6554 ns	8.4720 ns	174.128 ns	0.99	0.06	0.0343	-	-	144 B
String_Create	/base-path		?param1=value1&param2=value2&param3=value3	#fragment	185.893 ns	3.5433 ns	2.7663 ns	185.250 ns	1.00	0.03	0.0343	-	-	144 B
UriHelper_BuildRelative	/base-path	/path/one/two/three			240.085 ns	3.2488 ns	2.8800 ns	239.380 ns	1.00	0.00	0.0191	-	-	80 B
Single_Concat	/base-path	/path/one/two/three			224.022 ns	2.7651 ns	2.4512 ns	223.712 ns	0.93	0.01	0.0191	-	-	80 B
String_Create	/base-path	/path/one/two/three			246.030 ns	4.8594 ns	4.9903 ns	244.354 ns	1.03	0.03	0.0191	-	-	80 B
UriHelper_BuildRelative	/base-path	/path/one/two/three		#fragment	250.323 ns	3.2801 ns	2.9077 ns	249.957 ns	1.00	0.00	0.0439	-	-	184 B
Single_Concat	/base-path	/path/one/two/three		#fragment	242.748 ns	2.3555 ns	2.0881 ns	242.596 ns	0.97	0.01	0.0248	-	-	104 B
String_Create	/base-path	/path/one/two/three		#fragment	257.290 ns	3.4151 ns	2.8517 ns	257.640 ns	1.03	0.02	0.0248	-	-	104 B
UriHelper_BuildRelative	/base-path	/path/one/two/three	?param1=value1&param2=value2&param3=value3		330.477 ns	3.8466 ns	3.0032 ns	330.757 ns	1.00	0.00	0.0591	-	-	248 B
Single_Concat	/base-path	/path/one/two/three	?param1=value1&param2=value2&param3=value3		317.222 ns	5.0941 ns	6.6238 ns	315.922 ns	0.96	0.02	0.0401	-	-	168 B
String_Create	/base-path	/path/one/two/three	?param1=value1&param2=value2&param3=value3		316.704 ns	5.4259 ns	5.3290 ns	315.759 ns	0.96	0.02	0.0401	-	-	168 B
UriHelper_BuildRelative	/base-path	/path/one/two/three	?param1=value1&param2=value2&param3=value3	#fragment	340.993 ns	3.4605 ns	3.0676 ns	341.252 ns	1.00	0.00	0.0629	-	-	264 B
Single_Concat	/base-path	/path/one/two/three	?param1=value1&param2=value2&param3=value3	#fragment	318.045 ns	5.1664 ns	4.5799 ns	317.869 ns	0.93	0.02	0.0439	-	-	184 B
String_Create	/base-path	/path/one/two/three	?param1=value1&param2=value2&param3=value3	#fragment	337.393 ns	6.1599 ns	8.6353 ns	335.176 ns	0.99	0.03	0.0439	-	-	184 B

Code

[MemoryDiagnoser]
public class BuildRelativeBenchmark
{
    public IEnumerable<object[]> Data() => TestData.PathBasePathQueryFragment();

    [Benchmark(Baseline = true)]
    [ArgumentsSource(nameof(Data))]
    public string UriHelper_BuildRelative(PathString pathBase, PathString path, QueryString query, FragmentString fragment)
        => UriHelper.BuildRelative(pathBase, path, query, fragment);

    [Benchmark]
    [ArgumentsSource(nameof(Data))]
    public string Single_Concat(PathString pathBase, PathString path, QueryString query, FragmentString fragment)
    {
        if (pathBase.HasValue || path.HasValue)
        {
            return pathBase.ToUriComponent() + path.ToUriComponent() + query.ToUriComponent() + fragment.ToUriComponent();
        }
        else
        {
            return "/" + query.ToUriComponent() + fragment.ToUriComponent();
        }
    }

    private static readonly SpanAction<char, (string pathBase, string path, string query, string fragment)> InitializeStringAction = new(InitializeString);

    [Benchmark]
    [ArgumentsSource(nameof(Data))]
    public string String_Create(PathString pathBaseString, PathString pathString, QueryString queryString, FragmentString fragmentString)
    {
        var pathBase = pathBaseString.ToUriComponent();
        var path = pathString.ToUriComponent();
        var query = queryString.ToUriComponent();
        var fragment = fragmentString.ToUriComponent();

        var length = pathBase.Length + path.Length + query.Length + fragment.Length;

        if (string.IsNullOrEmpty(pathBase) && string.IsNullOrEmpty(path))
        {
            if (length == 0)
            {
                return "/";
            }

            path = "/";
            length++;
        }
        else
        {
            if (!string.IsNullOrEmpty(pathBase) && pathBase.Length == length)
            {
                return pathBase;
            }

            if (path.Length == length)
            {
                return path;
            }
        }

        return string.Create(length, (pathBase, path, query, fragment), InitializeStringSpanAction);
    }

    private static void InitializeString(Span<char> buffer, (string pathBase, string path, string query, string fragment) uriParts)
    {
        var index = 0;

        index = Copy(buffer, index, uriParts.pathBase);
        index = Copy(buffer, index, uriParts.path);
        index = Copy(buffer, index, uriParts.query);
        _ = Copy(buffer, index, uriParts.fragment);

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        static int Copy(Span<char> buffer, int index, string text)
        {
            if (!string.IsNullOrEmpty(text))
            {
                var span = text.AsSpan();
                span.CopyTo(buffer.Slice(index, span.Length));
                return index + span.Length;
            }

            return index;
        }
    }
}

public static class TestData
{
    private static readonly string[] basePaths = new[] { "", "/base-path", };
    private static readonly string[] paths = new[] { "", "/path/one/two/three", };
    private static readonly string[] queries = new[] { "", "?param1=value1&param2=value2&param3=value3", };
    private static readonly string[] fragments = new[] { "", "#fragment", };

    public static IEnumerable<object[]> PathBasePathQueryFragment()
    {
        foreach (var basePath in basePaths)
        {
            foreach (var path in paths)
            {
                foreach (var query in queries)
                {
                    foreach (var fragment in fragments)
                    {
                        yield return new object[] { new PathString(basePath), new PathString(path), new QueryString(query), new FragmentString(fragment), };
                    }
                }
            }
        }
    }
}

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