Path.Combine很方便,但是.NET框架中是否有类似的URL函数?

我正在寻找这样的语法:

Url.Combine("http://MyUrl.com/", "/Images/Image.jpg")

这将返回:

"http://MyUrl.com/Images/Image.jpg"


当前回答

所以我有另一种方法,类似于使用UriBuilder的每个人。

我不想拆分我的BaseUrl(它可以包含路径的一部分,例如。http://mybaseurl.com/dev/)正如javajavajavajava所做的那样。

下面的代码片段显示了代码+测试。

注意:此解决方案降低了主机并附加了一个端口。如果不需要这样做,可以通过例如利用UriBuilder的Uri属性来编写字符串表示。

  public class Tests
  {
         public static string CombineUrl (string baseUrl, string path)
         {
           var uriBuilder = new UriBuilder (baseUrl);
           uriBuilder.Path = Path.Combine (uriBuilder.Path, path);
           return uriBuilder.ToString();
         }

         [TestCase("http://MyUrl.com/", "/Images/Image.jpg", "http://myurl.com:80/Images/Image.jpg")]
         [TestCase("http://MyUrl.com/basePath", "/Images/Image.jpg", "http://myurl.com:80/Images/Image.jpg")]
         [TestCase("http://MyUrl.com/basePath", "Images/Image.jpg", "http://myurl.com:80/basePath/Images/Image.jpg")]
         [TestCase("http://MyUrl.com/basePath/", "Images/Image.jpg", "http://myurl.com:80/basePath/Images/Image.jpg")]
         public void Test1 (string baseUrl, string path, string expected)
         {
           var result = CombineUrl (baseUrl, path);

           Assert.That (result, Is.EqualTo (expected));
         }
  }

在Windows 10上使用.NET Core 2.1进行测试。

为什么这样做?

尽管Path.Combine将返回反斜杠(至少在Windows上),但UriBuilder在路径设置器中处理这种情况。

摘自https://github.com/dotnet/corefx/blob/master/src/System.Private.Uri/src/System/UriBuilder.cs(注意调用字符串。替换)

[AllowNull]
public string Path
{
      get
      {
          return _path;
      }
      set
      {
          if ((value == null) || (value.Length == 0))
          {
              value = "/";
          }
          _path = Uri.InternalEscapeString(value.Replace('\\', '/'));
          _changed = true;
      }
 }

这是最好的方法吗?

当然,这个解决方案非常自我描述(至少在我看来)。但是,您依赖的是.NETAPI中的未记录(至少我在快速谷歌搜索中没有发现任何内容)“功能”。这可能会随着将来的版本而改变,因此请将方法与测试结合起来。

中有测试https://github.com/dotnet/corefx/blob/master/src/System.Private.Uri/tests/FunctionalTests/UriBuilderTests.cs(Path_Get_Set),用于检查\是否正确转换。

附带说明:如果Uri将用于System.Uri构造函数,则也可以直接使用UriBuilder.Uri属性。

其他回答

根据您提供的示例URL,我将假设您希望组合与站点相关的URL。

基于这一假设,我将提出这个解决方案,作为对您的问题的最恰当的回答:“Path.Combine很方便,在URL框架中有类似的功能吗?”

由于URL框架中有一个类似的函数,我建议正确的方法是:“VirtualPathUtility.Compine”方法。下面是MSDN参考链接:VirtualPathUtility.Combine方法

有一个警告:我认为这只适用于与您的网站相关的url(即,您不能使用它来生成指向另一个网站的链接。例如,var url=VirtualPathUtility.Combine(“www.google.com”,“accounts/widgets”);)。

我有一个无需分配的字符串创建版本,我一直在成功地使用它。

注:

对于第一个字符串:它使用TrimEnd(分隔符)修剪分隔符,因此仅从字符串的末尾开始。对于余数:它使用Trim(分隔符)修剪分隔符-因此路径的起点和终点都是它不附加尾部斜杠/分隔符。虽然可以做一个简单的修改来增加这个能力。

希望你觉得这很有用!

/// <summary>
/// This implements an allocation-free string creation to construct the path.
/// This uses 3.5x LESS memory and is 2x faster than some alternate methods (StringBuilder, interpolation, string.Concat, etc.).
/// </summary>
/// <param name="str"></param>
/// <param name="paths"></param>
/// <returns></returns>
public static string ConcatPath(this string str, params string[] paths)
{
    const char separator = '/';
    if (str == null) throw new ArgumentNullException(nameof(str));

    var list = new List<ReadOnlyMemory<char>>();
    var first = str.AsMemory().TrimEnd(separator);

    // get length for intial string after it's trimmed
    var length = first.Length;
    list.Add(first);

    foreach (var path in paths)
    {
        var newPath = path.AsMemory().Trim(separator);
        length += newPath.Length + 1;
        list.Add(newPath);
    }

    var newString = string.Create(length, list, (chars, state) =>
    {
        // NOTE: We don't access the 'list' variable in this delegate since 
        // it would cause a closure and allocation. Instead we access the state parameter.

        // track our position within the string data we are populating
        var position = 0;

        // copy the first string data to index 0 of the Span<char>
        state[0].Span.CopyTo(chars);

        // update the position to the new length
        position += state[0].Span.Length;

        // start at index 1 when slicing
        for (var i = 1; i < state.Count; i++)
        {
            // add a separator in the current position and increment position by 1
            chars[position++] = separator;

            // copy each path string to a slice at current position
            state[i].Span.CopyTo(chars.Slice(position));

            // update the position to the new length
            position += state[i].Length;
        }
    });
    return newString;
}

基准DotNet输出:

|                Method |     Mean |    Error |   StdDev |   Median | Ratio | RatioSD |  Gen 0 | Allocated |
|---------------------- |---------:|---------:|---------:|---------:|------:|--------:|-------:|----------:|
| ConcatPathWithBuilder | 404.1 ns | 27.35 ns | 78.48 ns | 380.3 ns |  1.00 |    0.00 | 0.3347 |   1,400 B |
|            ConcatPath | 187.2 ns |  5.93 ns | 16.44 ns | 183.2 ns |  0.48 |    0.10 | 0.0956 |     400 B |

Uri有一个构造函数可以为您执行此操作:new Uri(Uri baseUri,string relativeUri)

下面是一个示例:

Uri baseUri = new Uri("http://www.contoso.com");
Uri myUri = new Uri(baseUri, "catalog/shownew.htm");

编辑注意:小心,这种方法并不能像预期的那样工作。在某些情况下,它可以剪切baseUri的一部分。查看评论和其他答案。

最近,Combine方法被添加到Energy.Core包中,所以您可能希望使用它来连接URL部分。

    string url;
    url = Energy.Base.Url.Combine("https://www.youtube.com", "watch?v=NHCgbs3TcYg");
    Console.WriteLine(url);
    url = Energy.Base.Url.Combine("https://www.youtube.com", "watch?v=NHCgbs3TcYg", "t=150");
    Console.WriteLine(url);

此外,它将识别参数部分,因此它将按照您的预期工作(用斜线连接路径,用&符号连接参数)。

https://www.youtube.com/watch?v=NHCgbs3TcYghttps://www.youtube.com/watch?v=NHCgbs3TcYg&t=150

Energy.Base.Url类文档

NuGet图库上的软件包

代码示例

我创建了这个功能,可以让您的生活更轻松:

    /// <summary>
    /// The ultimate Path combiner of all time
    /// </summary>
    /// <param name="IsURL">
    /// true - if the paths are Internet URLs, false - if the paths are local URLs, this is very important as this will be used to decide which separator will be used.
    /// </param>
    /// <param name="IsRelative">Just adds the separator at the beginning</param>
    /// <param name="IsFixInternal">Fix the paths from within (by removing duplicate separators and correcting the separators)</param>
    /// <param name="parts">The paths to combine</param>
    /// <returns>the combined path</returns>
    public static string PathCombine(bool IsURL , bool IsRelative , bool IsFixInternal , params string[] parts)
    {
        if (parts == null || parts.Length == 0) return string.Empty;
        char separator = IsURL ? '/' : '\\';

        if (parts.Length == 1 && IsFixInternal)
        {
            string validsingle;
            if (IsURL)
            {
                validsingle = parts[0].Replace('\\' , '/');
            }
            else
            {
                validsingle = parts[0].Replace('/' , '\\');
            }
            validsingle = validsingle.Trim(separator);
            return (IsRelative ? separator.ToString() : string.Empty) + validsingle;
        }

        string final = parts
            .Aggregate
            (
            (string first , string second) =>
            {
                string validfirst;
                string validsecond;
                if (IsURL)
                {
                    validfirst = first.Replace('\\' , '/');
                    validsecond = second.Replace('\\' , '/');
                }
                else
                {
                    validfirst = first.Replace('/' , '\\');
                    validsecond = second.Replace('/' , '\\');
                }
                var prefix = string.Empty;
                if (IsFixInternal)
                {
                    if (IsURL)
                    {
                        if (validfirst.Contains("://"))
                        {
                            var tofix = validfirst.Substring(validfirst.IndexOf("://") + 3);
                            prefix = validfirst.Replace(tofix , string.Empty).TrimStart(separator);

                            var tofixlist = tofix.Split(new[] { separator } , StringSplitOptions.RemoveEmptyEntries);

                            validfirst = separator + string.Join(separator.ToString() , tofixlist);
                        }
                        else
                        {
                            var firstlist = validfirst.Split(new[] { separator } , StringSplitOptions.RemoveEmptyEntries);
                            validfirst = string.Join(separator.ToString() , firstlist);
                        }

                        var secondlist = validsecond.Split(new[] { separator } , StringSplitOptions.RemoveEmptyEntries);
                        validsecond = string.Join(separator.ToString() , secondlist);
                    }
                    else
                    {
                        var firstlist = validfirst.Split(new[] { separator } , StringSplitOptions.RemoveEmptyEntries);
                        var secondlist = validsecond.Split(new[] { separator } , StringSplitOptions.RemoveEmptyEntries);

                        validfirst = string.Join(separator.ToString() , firstlist);
                        validsecond = string.Join(separator.ToString() , secondlist);
                    }
                }
                return prefix + validfirst.Trim(separator) + separator + validsecond.Trim(separator);
            }
            );
        return (IsRelative ? separator.ToString() : string.Empty) + final;
    }

它适用于URL和普通路径。

用法:

    // Fixes internal paths
    Console.WriteLine(PathCombine(true , true , true , @"\/\/folder 1\/\/\/\\/\folder2\///folder3\\/" , @"/\somefile.ext\/\//\"));
    // Result: /folder 1/folder2/folder3/somefile.ext

    // Doesn't fix internal paths
    Console.WriteLine(PathCombine(true , true , false , @"\/\/folder 1\/\/\/\\/\folder2\///folder3\\/" , @"/\somefile.ext\/\//\"));
    //result : /folder 1//////////folder2////folder3/somefile.ext

    // Don't worry about URL prefixes when fixing internal paths
    Console.WriteLine(PathCombine(true , false , true , @"/\/\/https:/\/\/\lul.com\/\/\/\\/\folder2\///folder3\\/" , @"/\somefile.ext\/\//\"));
    // Result: https://lul.com/folder2/folder3/somefile.ext

    Console.WriteLine(PathCombine(false , true , true , @"../../../\\..\...\./../somepath" , @"anotherpath"));
    // Result: \..\..\..\..\...\.\..\somepath\anotherpath