验证字符串是否是有效的电子邮件地址的最优雅的代码是什么?
当前回答
对@齿轮回答做了一点修改
public static bool IsValidEmail(this string email)
{
// skip the exception & return early if possible
if (email.IndexOf("@") <= 0) return false;
try
{
var address = new MailAddress(email);
return address.Address == email;
}
catch
{
return false;
}
}
其他回答
我发现这个正则表达式在检查@标记以外的东西和接受奇怪的边缘情况之间是一个很好的权衡:
^[^@\s]+@[^@\s]+(\.[^@\s]+)+$
它至少会让你在@标记周围放一些东西，并且至少放一个正常的域。
我最终使用了这个正则表达式，因为它成功地验证了逗号、注释、Unicode字符和IP(v4)域地址。
有效地址为:
“@example。org (评论)test@example。org тест@example。org ტესტი@example。org test@[192.168 . 1章1段]
public const string REGEX_EMAIL = @"^(((\([\w!#$%&'*+\/=?^_`{|}~-]*\))?[^<>()[\]\\.,;:\s@\""]+(\.[^<>()[\]\\.,;:\s@\""]+)*)|(\"".+\""))(\([\w!#$%&'*+\/=?^_`{|}~-]*\))?@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$";
在c#的regex中有文化问题，而不是js。所以我们需要在US模式下使用regex进行邮件检查。如果你不使用ECMAScript模式，你的语言特殊字符是在A-Z与正则表达式中隐含的。
Regex.IsMatch(email, @"^([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9_\-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$", RegexOptions.ECMAScript)
正如在许多回答中提到的，电子邮件地址的领域是复杂的。在这种情况下，我强烈反对使用正则表达式。那些匹配(大多数)用例的异常复杂，难以读取，因此也难以维护。此外，它们仍然难以支持所有病例，而且速度缓慢。
微软的EmailAddress类在这方面有所帮助，但我认为也不是完美的。在几年前的一个开源项目中，我尝试使用定制的EmailParser。
在[EmailAddress]https://github.com/Qowaiv/Qowaiv/blob/master/src/Qowaiv/EmailAddress.cs中使用。
通过使用这种方法，不仅可以验证电子邮件地址，还可以清除显示名称的多种格式，去掉mailto:-前缀，并根据ip地址规范化域字面量，并将所有内容小写(注意，本地部分是大小写敏感的)。
你的解决方案应该支持的场景(上面提到的就是):
[TestCase(null)]
[TestCase("")]
[TestCase("..@test.com")]
[TestCase(".a@test.com")]
[TestCase("ab@sd@dd")]
[TestCase(".@s.dd")]
[TestCase("ab@988.120.150.10")]
[TestCase("ab@120.256.256.120")]
[TestCase("ab@120.25.1111.120")]
[TestCase("ab@[188.120.150.10")]
[TestCase("ab@188.120.150.10]")]
[TestCase("ab@[188.120.150.10].com")]
[TestCase("a@b.-de.cc")]
[TestCase("a@bde-.cc")]
[TestCase("a@bde.c-c")]
[TestCase("a@bde.cc.")]
[TestCase("ab@b+de.cc")]
[TestCase("a..b@bde.cc")]
[TestCase("_@bde.cc,")]
[TestCase("plainaddress")]
[TestCase("plain.address")]
[TestCase("@%^%#$@#$@#.com")]
[TestCase("@domain.com")]
[TestCase("Joe Smith <email@domain.com>")]
[TestCase("email.domain.com")]
[TestCase("email@domain@domain.com")]
[TestCase(".email@domain.com")]
[TestCase("email.@domain.com")]
[TestCase("email..email@domain.com")]
[TestCase("email@-domain.com")]
[TestCase("email@domain-.com")]
[TestCase("email@domain.com-")]
[TestCase("email@.domain.com")]
[TestCase("email@domain.com.")]
[TestCase("email@domain..com")]
[TestCase("email@111.222.333")]
[TestCase("email@111.222.333.256")]
[TestCase("email@[123.123.123.123")]
[TestCase("email@[123.123.123].123")]
[TestCase("email@123.123.123.123]")]
[TestCase("email@123.123.[123.123]")]
[TestCase("email@{leftbracket.com")]
[TestCase("email@rightbracket}.com")]
[TestCase("email@p|pe.com")]
[TestCase("isis@100%.nl")]
[TestCase("email@dollar$.com")]
[TestCase("email@r&d.com")]
[TestCase("email@#hash.com")]
[TestCase("email@wave~tilde.com")]
[TestCase("email@exclamation!mark.com")]
[TestCase("email@question?mark.com")]
[TestCase("email@obelix*asterisk.com")]
[TestCase("email@grave`accent.com")]
[TestCase("email@colon:colon.com")]
[TestCase("email@caret^xor.com")]
[TestCase("email@=qowaiv.com")]
[TestCase("email@plus+.com")]
[TestCase("email@domain.com>")]
[TestCase("email( (nested) )@plus.com")]
[TestCase("email)mirror(@plus.com")]
[TestCase("email@plus.com (not closed comment")]
[TestCase("email(with @ in comment)plus.com")]
[TestCase(@"""Joe Smith email@domain.com")]
[TestCase(@"""Joe Smith' email@domain.com")]
[TestCase(@"""Joe Smith""email@domain.com")]
[TestCase("email@mailto:domain.com")]
[TestCase("mailto:mailto:email@domain.com")]
[TestCase("Display Name <email@plus.com> (after name with display)")]
[TestCase("ReDoSaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa@aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa.aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa")]
public void IsInvalid(string email)
{
Assert.IsFalse(EmailAddress.IsValid(email), email);
}
[TestCase("w@com")]
[TestCase("w.b.f@test.com")]
[TestCase("w.b.f@test.museum")]
[TestCase("a.a@test.com")]
[TestCase("ab@288.120.150.10.com")]
[TestCase("ab@188.120.150.10")]
[TestCase("ab@1.0.0.10")]
[TestCase("ab@120.25.254.120")]
[TestCase("ab@01.120.150.1")]
[TestCase("ab@88.120.150.021")]
[TestCase("ab@88.120.150.01")]
[TestCase("ab@[120.254.254.120]")]
[TestCase("local@2001:0db8:85a3:0000:0000:8a2e:0370:7334")]
[TestCase("local@[2001:0db8:85a3:0000:0000:8a2e:0370:7334]")]
[TestCase("2@bde.cc")]
[TestCase("-@bde.cc")]
[TestCase("a2@bde.cc")]
[TestCase("a-b@bde.cc")]
[TestCase("ab@b-de.cc")]
[TestCase("a+b@bde.cc")]
[TestCase("f.f.f@bde.cc")]
[TestCase("ab_c@bde.cc")]
[TestCase("_-_@bde.cc")]
[TestCase("k.haak@12move.nl")]
[TestCase("K.HAAK@12MOVE.NL")]
[TestCase("email@domain.com")]
[TestCase("email@domain")]
[TestCase("あいうえお@domain.com")]
[TestCase("local@あいうえお.com")]
[TestCase("firstname.lastname@domain.com")]
[TestCase("email@subdomain.domain.com")]
[TestCase("firstname+lastname@domain.com")]
[TestCase("email@123.123.123.123")]
[TestCase("email@[123.123.123.123]")]
[TestCase("1234567890@domain.com")]
[TestCase("a@domain.com")]
[TestCase("a.b.c.d@domain.com")]
[TestCase("aap.123.noot.mies@domain.com")]
[TestCase("1@domain.com")]
[TestCase("email@domain-one.com")]
[TestCase("_______@domain.com")]
[TestCase("email@domain.topleveldomain")]
[TestCase("email@domain.co.jp")]
[TestCase("firstname-lastname@domain.com")]
[TestCase("firstname-lastname@d.com")]
[TestCase("FIRSTNAME-LASTNAME@d--n.com")]
[TestCase("first-name-last-name@d-a-n.com")]
[TestCase("{local{name{{with{@leftbracket.com")]
[TestCase("}local}name}}with{@rightbracket.com")]
[TestCase("|local||name|with|@pipe.com")]
[TestCase("%local%%name%with%@percentage.com")]
[TestCase("$local$$name$with$@dollar.com")]
[TestCase("&local&&name&with&$@amp.com")]
[TestCase("#local##name#with#@hash.com")]
[TestCase("~local~~name~with~@tilde.com")]
[TestCase("!local!!name!with!@exclamation.com")]
[TestCase("?local??name?with?@question.com")]
[TestCase("*local**name*with*@asterisk.com")]
[TestCase("`local``name`with`@grave-accent.com")]
[TestCase("^local^^name^with^@xor.com")]
[TestCase("=local==name=with=@equality.com")]
[TestCase("+local++name+with+@equality.com")]
[TestCase("Joe Smith <email@domain.com>")]
[TestCase("email@domain.com (joe Smith)")]
[TestCase(@"""Joe Smith"" email@domain.com")]
[TestCase(@"""Joe\\tSmith"" email@domain.com")]
[TestCase(@"""Joe\""Smith"" email@domain.com")]
[TestCase(@"Test |<gaaf <email@domain.com>")]
[TestCase("MailTo:casesensitve@domain.com")]
[TestCase("mailto:email@domain.com")]
[TestCase("Joe Smith <mailto:email@domain.com>")]
[TestCase("Joe Smith <mailto:email(with comment)@domain.com>")]
[TestCase(@"""With extra < within quotes"" Display Name<email@domain.com>")]
[TestCase("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa@aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa.aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa")]
public void IsValid(string email)
{
Assert.IsTrue(EmailAddress.IsValid(email), email);
}
另一个正则表达式匹配答案:
/// <summary>
/// Validates the email input
/// </summary>
internal static bool ValidateEmail(string _emailAddress)
{
string _regexPattern = @"^(([\w-]+\.)+[\w-]+|([a-zA-Z]{1}|[\w-]{2,}))@"
+ @"((([0-1]?[0-9]{1,2}|25[0-5]|2[0-4][0-9])\.([0-1]?[0-9]{1,2}|25[0-5]|2[0-4][0-9])\."
+ @"([0-1]?[0-9]{1,2}|25[0-5]|2[0-4][0-9])\.([0-1]?[0-9]{1,2}|25[0-5]|2[0-4][0-9])){1}|"
+ @"([a-zA-Z]+[\w-]+\.)+[a-zA-Z]{2,4})$";
return (string.IsNullOrEmpty(_emailAddress) == false && System.Text.RegularExpressions.Regex.IsMatch(_emailAddress, _regexPattern))
? true
: false;
}
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