为此,我们需要:
- 规范化文本
- 删除所有变音符号
- 替换国际字符
- 能够缩短文本以匹配 SEO 阈值
我想要一个函数来生成整个字符串,并有一个可能的最大长度的输入,这就是结果。
public static class StringHelper
{
/// <summary>
/// Creates a URL And SEO friendly slug
/// </summary>
/// <param name="text">Text to slugify</param>
/// <param name="maxLength">Max length of slug</param>
/// <returns>URL and SEO friendly string</returns>
public static string UrlFriendly(string text, int maxLength = 0)
{
// Return empty value if text is null
if (text == null) return "";
var normalizedString = text
// Make lowercase
.ToLowerInvariant()
// Normalize the text
.Normalize(NormalizationForm.FormD);
var stringBuilder = new StringBuilder();
var stringLength = normalizedString.Length;
var prevdash = false;
var trueLength = 0;
char c;
for (int i = 0; i < stringLength; i++)
{
c = normalizedString[i];
switch (CharUnicodeInfo.GetUnicodeCategory(c))
{
// Check if the character is a letter or a digit if the character is a
// international character remap it to an ascii valid character
case UnicodeCategory.LowercaseLetter:
case UnicodeCategory.UppercaseLetter:
case UnicodeCategory.DecimalDigitNumber:
if (c < 128)
stringBuilder.Append(c);
else
stringBuilder.Append(ConstHelper.RemapInternationalCharToAscii(c));
prevdash = false;
trueLength = stringBuilder.Length;
break;
// Check if the character is to be replaced by a hyphen but only if the last character wasn't
case UnicodeCategory.SpaceSeparator:
case UnicodeCategory.ConnectorPunctuation:
case UnicodeCategory.DashPunctuation:
case UnicodeCategory.OtherPunctuation:
case UnicodeCategory.MathSymbol:
if (!prevdash)
{
stringBuilder.Append('-');
prevdash = true;
trueLength = stringBuilder.Length;
}
break;
}
// If we are at max length, stop parsing
if (maxLength > 0 && trueLength >= maxLength)
break;
}
// Trim excess hyphens
var result = stringBuilder.ToString().Trim('-');
// Remove any excess character to meet maxlength criteria
return maxLength <= 0 || result.Length <= maxLength ? result : result.Substring(0, maxLength);
}
}
该助手用于将一些国际字符重新映射为可读字符。
public static class ConstHelper
{
/// <summary>
/// Remaps international characters to ascii compatible ones
/// based of: https://meta.stackexchange.com/questions/7435/non-us-ascii-characters-dropped-from-full-profile-url/7696#7696
/// </summary>
/// <param name="c">Charcter to remap</param>
/// <returns>Remapped character</returns>
public static string RemapInternationalCharToAscii(char c)
{
string s = c.ToString().ToLowerInvariant();
if ("àåáâäãåą".Contains(s))
{
return "a";
}
else if ("èéêëę".Contains(s))
{
return "e";
}
else if ("ìíîïı".Contains(s))
{
return "i";
}
else if ("òóôõöøőð".Contains(s))
{
return "o";
}
else if ("ùúûüŭů".Contains(s))
{
return "u";
}
else if ("çćčĉ".Contains(s))
{
return "c";
}
else if ("żźž".Contains(s))
{
return "z";
}
else if ("śşšŝ".Contains(s))
{
return "s";
}
else if ("ñń".Contains(s))
{
return "n";
}
else if ("ýÿ".Contains(s))
{
return "y";
}
else if ("ğĝ".Contains(s))
{
return "g";
}
else if (c == 'ř')
{
return "r";
}
else if (c == 'ł')
{
return "l";
}
else if (c == 'đ')
{
return "d";
}
else if (c == 'ß')
{
return "ss";
}
else if (c == 'þ')
{
return "th";
}
else if (c == 'ĥ')
{
return "h";
}
else if (c == 'ĵ')
{
return "j";
}
else
{
return "";
}
}
}
该功能会像这样工作
const string text = "ICH MUß EINIGE CRÈME BRÛLÉE HABEN";
Console.WriteLine(StringHelper.URLFriendly(text));
// Output:
// ich-muss-einige-creme-brulee-haben
这个问题已经在这里回答了很多次,但没有一个优化过。您可以在 github 上找到完整的源代码以及一些示例。您可以从Johan Boström 的博客中阅读更多内容。更多信息与 .NET 4.5+ 和 .NET Core 兼容。