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"
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
如果您不想拥有像Flurl这样的依赖项,可以使用它的源代码:
/// <summary>
/// Basically a Path.Combine for URLs. Ensures exactly one '/' separates each segment,
/// and exactly on '&' separates each query parameter.
/// URL-encodes illegal characters but not reserved characters.
/// </summary>
/// <param name="parts">URL parts to combine.</param>
public static string Combine(params string[] parts) {
if (parts == null)
throw new ArgumentNullException(nameof(parts));
string result = "";
bool inQuery = false, inFragment = false;
string CombineEnsureSingleSeparator(string a, string b, char separator) {
if (string.IsNullOrEmpty(a)) return b;
if (string.IsNullOrEmpty(b)) return a;
return a.TrimEnd(separator) + separator + b.TrimStart(separator);
}
foreach (var part in parts) {
if (string.IsNullOrEmpty(part))
continue;
if (result.EndsWith("?") || part.StartsWith("?"))
result = CombineEnsureSingleSeparator(result, part, '?');
else if (result.EndsWith("#") || part.StartsWith("#"))
result = CombineEnsureSingleSeparator(result, part, '#');
else if (inFragment)
result += part;
else if (inQuery)
result = CombineEnsureSingleSeparator(result, part, '&');
else
result = CombineEnsureSingleSeparator(result, part, '/');
if (part.Contains("#")) {
inQuery = false;
inFragment = true;
}
else if (!inFragment && part.Contains("?")) {
inQuery = true;
}
}
return EncodeIllegalCharacters(result);
}
/// <summary>
/// URL-encodes characters in a string that are neither reserved nor unreserved. Avoids encoding reserved characters such as '/' and '?'. Avoids encoding '%' if it begins a %-hex-hex sequence (i.e. avoids double-encoding).
/// </summary>
/// <param name="s">The string to encode.</param>
/// <param name="encodeSpaceAsPlus">If true, spaces will be encoded as + signs. Otherwise, they'll be encoded as %20.</param>
/// <returns>The encoded URL.</returns>
public static string EncodeIllegalCharacters(string s, bool encodeSpaceAsPlus = false) {
if (string.IsNullOrEmpty(s))
return s;
if (encodeSpaceAsPlus)
s = s.Replace(" ", "+");
// Uri.EscapeUriString mostly does what we want - encodes illegal characters only - but it has a quirk
// in that % isn't illegal if it's the start of a %-encoded sequence https://stackoverflow.com/a/47636037/62600
// no % characters, so avoid the regex overhead
if (!s.Contains("%"))
return Uri.EscapeUriString(s);
// pick out all %-hex-hex matches and avoid double-encoding
return Regex.Replace(s, "(.*?)((%[0-9A-Fa-f]{2})|$)", c => {
var a = c.Groups[1].Value; // group 1 is a sequence with no %-encoding - encode illegal characters
var b = c.Groups[2].Value; // group 2 is a valid 3-character %-encoded sequence - leave it alone!
return Uri.EscapeUriString(a) + b;
});
}
其他回答
组合URL的多个部分可能有点棘手。可以使用双参数构造函数Uri(baseUri、relativeUri),也可以使用Uri.TryCreate()实用程序函数。
在任何一种情况下,您都可能会返回错误的结果,因为这些方法会不断截断第一个参数baseUri的相对部分,例如http://google.com/some/thing到http://google.com.
为了能够将多个部分合并为最终URL,可以复制以下两个函数:
public static string Combine(params string[] parts)
{
if (parts == null || parts.Length == 0) return string.Empty;
var urlBuilder = new StringBuilder();
foreach (var part in parts)
{
var tempUrl = tryCreateRelativeOrAbsolute(part);
urlBuilder.Append(tempUrl);
}
return VirtualPathUtility.RemoveTrailingSlash(urlBuilder.ToString());
}
private static string tryCreateRelativeOrAbsolute(string s)
{
System.Uri uri;
System.Uri.TryCreate(s, UriKind.RelativeOrAbsolute, out uri);
string tempUrl = VirtualPathUtility.AppendTrailingSlash(uri.ToString());
return tempUrl;
}
完整的代码和单元测试可以在https://uricombine.codeplex.com/SourceControl/latest#UriCombine/Uri.cs
我有单元测试来涵盖三种最常见的情况:
这两种方法都有效:
Uri final = new Uri(Regex.Replace(baseUrl + "/" + relativePath, "(?<!http:)/{2,}", "/"));
Or
Uri final =new Uri(string.Format("{0}/{1}", baseUrl.ToString().TrimEnd('/'), relativePath.ToString().TrimStart('/')));
即,如果
baseUrl = "http://tesrurl.test.com/Int18"
and
relativePath = "To_Folder"
output = http://tesrurl.test.com/Int18/To_Folder
以下代码将出现一些错误:
// If you use the below code, some issues will be there in the final URI
Uri final = new Uri(baseUrl, relativePath);
Use:
private Uri UriCombine(string path1, string path2, string path3 = "", string path4 = "")
{
string path = System.IO.Path.Combine(path1, path2.TrimStart('\\', '/'), path3.TrimStart('\\', '/'), path4.TrimStart('\\', '/'));
string url = path.Replace('\\','/');
return new Uri(url);
}
它的好处是行为与Path.Combine完全相同。
我还没有使用以下代码,但在我的互联网旅行中发现了它,以解决URL组合问题-希望它是一个简洁(并且成功!)的答案:
VirtualPathUtility.Combine
我的通用解决方案:
public static string Combine(params string[] uriParts)
{
string uri = string.Empty;
if (uriParts != null && uriParts.Any())
{
char[] trims = new char[] { '\\', '/' };
uri = (uriParts[0] ?? string.Empty).TrimEnd(trims);
for (int i = 1; i < uriParts.Length; i++)
{
uri = string.Format("{0}/{1}", uri.TrimEnd(trims), (uriParts[i] ?? string.Empty).TrimStart(trims));
}
}
return uri;
}