XML规范中定义了一系列有效的XML字符:
#x9 | #xA | #xD | [#x20-#xD7FF] | [#xE000-#xFFFD] | [#x10000-#x10FFFF]
我的问题是是否可以使用Unicode通用类别而不实际硬编码代码点来制作此(或其反向)的PCRE正则表达式。 反向可能是像[\p{Cc}\p{Cs}\p{Cn}]这样的东西,但是它没有正确覆盖换行符和制表符,并且错过了一些其他无效字符。我知道这并不完全回答你的问题,但有一些相关信息可能会对你有帮助:
用于匹配有效XML字符的正则表达式:
[\u0009\u000a\u000d\u0020-\uD7FF\uE000-\uFFFD]
因此,为了从XML中删除无效字符,您可以执行以下操作:
// filters control characters but allows only properly-formed surrogate sequences
private static Regex _invalidXMLChars = new Regex(
@"(?<![\uD800-\uDBFF])[\uDC00-\uDFFF]|[\uD800-\uDBFF](?![\uDC00-\uDFFF])|[\x00-\x08\x0B\x0C\x0E-\x1F\x7F-\x9F\uFEFF\uFFFE\uFFFF]",
RegexOptions.Compiled);
/// <summary>
/// removes any unusual unicode characters that can't be encoded into XML
/// </summary>
public static string RemoveInvalidXMLChars(string text)
{
if (string.IsNullOrEmpty(text)) return "";
return _invalidXMLChars.Replace(text, "");
}
我请我们公司的正则表达式/XML专家他曾发表过获得4400多个赞的帖子检查了这个问题,他认为没有问题。
private String filterContent(String content) {
return content.replaceAll("[^\\u0009\\u000a\\u000d\\u0020-\\uD7FF\\uE000-\\uFFFD]", "");
}
\\u000a\\u000d
是有效的字符。 - schoetbi<element></element>
),那么上述解决方案对我无效。下面的代码会出现错误:string xmlFormat = "<element>{0}</element>";
string invalid = " ";
string xml = string.Format(xmlFormat, invalid);
xml = Regex.Replace(xml, @"[\x01-\x08\x0B\x0C\x0E\x0F\u0000-\u0008\u000B\u000C\u000E-\u001F]", "");
XDocument.Parse(xml);
[Fact]
public void validate_that_RemoveInvalidData_only_remove_all_invalid_data()
{
string xmlFormat = "<element>{0}</element>";
string[] allAscii = (Enumerable.Range('\x1', 300).Select(x => ((char)x).ToString()).ToArray());
string[] allAsciiInHexCode = (Enumerable.Range('\x1', 300).Select(x => "&#x" + (x).ToString("X") + ";").ToArray());
string[] allAsciiInHexCodeLoweCase = (Enumerable.Range('\x1', 300).Select(x => "&#x" + (x).ToString("x") + ";").ToArray());
bool hasParserError = false;
IXmlSanitizer sanitizer = new XmlSanitizer();
foreach (var test in allAscii.Concat(allAsciiInHexCode).Concat(allAsciiInHexCodeLoweCase))
{
bool shouldBeRemoved = false;
string xml = string.Format(xmlFormat, test);
try
{
XDocument.Parse(xml);
shouldBeRemoved = false;
}
catch (Exception e)
{
if (test != "<" && test != "&") //these char are taken care of automatically by my convertor so don't need to test. You might need to add these.
{
shouldBeRemoved = true;
}
}
int xmlCurrentLength = xml.Length;
int xmlLengthAfterSanitize = Regex.Replace(xml, @"&#x([0-8BCEF]|1[0-9A-F]);|[\u0000-\u0008\u000B\u000C\u000E-\u001F]", "").Length;
if ((shouldBeRemoved && xmlCurrentLength == xmlLengthAfterSanitize) //it wasn't properly Removed
||(!shouldBeRemoved && xmlCurrentLength != xmlLengthAfterSanitize)) //it was removed but shouldn't have been
{
hasParserError = true;
Console.WriteLine(test + xml);
}
}
Assert.Equal(false, hasParserError);
}
使用 XmlConvert.IsXmlChar 方法 是在 .NET Framework 4.0 可用的另一种在 C# 中删除不正确的 XML 字符的方法。
public static string RemoveInvalidXmlChars(string content)
{
return new string(content.Where(ch => System.Xml.XmlConvert.IsXmlChar(ch)).ToArray());
}
public static bool CheckValidXmlChars(string content)
{
return content.All(ch => System.Xml.XmlConvert.IsXmlChar(ch));
}
.Net Fiddle - https://dotnetfiddle.net/v1TNus
例如,垂直制表符(\v)在XML中无效,它是有效的UTF-8,但不是有效的XML 1.0,甚至许多库(包括libxml2)都会忽略它并静默输出无效的XML。
在PHP中,正则表达式看起来像下面这样:
protected function isStringValid($string)
{
$regex = '/[^\x{9}\x{a}\x{d}\x{20}-\x{D7FF}\x{E000}-\x{FFFD}\x{10000}-\x{10FFFF}]+/u';
return (preg_match($regex, $string, $matches) === 0);
}
这将处理XML规范中的所有3个范围:
#x9 | #xA | #xD | [#x20-#xD7FF] | [#xE000-#xFFFD] | [#x10000-#x10FFFF]