[英]Extract (multiple) emails from user-input text into the MailAddress format (.NET)
The MailAddress class doesn't provide a way to parse a string with multiple emails. MailAddress类不提供解析具有多个电子邮件的字符串的方法。 The MailAddressCollection class does , but it only accepts CSV and does not allow commas inside of quotes .
MailAddressCollection类可以 ,但它只接受CSV并且不允许在引号内使用逗号 。 I am looking for a text processor to create a collection of emails from user input without these restrictions.
我正在寻找一个文本处理器来创建一组来自用户输入的电子邮件,没有这些限制。
The processor should take comma- or semicolon-separated values in any of these formats: 处理器应采用以下任何格式的逗号或分号分隔值:
"First Middle Last" <fml@example.com>
First Middle Last <fml@example.com>
fml@example.com
"Last, First" <fml@example.com>
The MailAddressCollection.Add() routine supports a comma delimited address list. MailAddressCollection.Add()例程支持逗号分隔的地址列表。
Dim mc As New Net.Mail.MailAddressCollection()
mc.Add("Bob <bob@bobmail.com>, mary@marymail.com, ""John Doe"" <john.doe@myemail.com>")
For Each m As Net.Mail.MailAddress In mc
Debug.Print("{0} ({1})", m.DisplayName, m.Address)
Next
Output: 输出:
Bob (bob@bobmail.com)
(mary@marymail.com)
John Doe (john.doe@myemail.com)
The open source library DotNetOpenMail (old) has an EmailAddress class that can parse almost all legal forms of email addresses, and an EmailAddressCollection . 开源库DotNetOpenMail (旧)有一个EmailAddress类,可以解析几乎所有合法形式的电子邮件地址,以及EmailAddressCollection 。 You could start there.
你可以从那里开始。
After asking a related question , I became aware of a better method: 在询问相关问题后 ,我意识到了一种更好的方法:
/// <summary>
/// Extracts email addresses in the following formats:
/// "Tom W. Smith" <tsmith@contoso.com>
/// "Smith, Tom" <tsmith@contoso.com>
/// Tom W. Smith <tsmith@contoso.com>
/// tsmith@contoso.com
/// Multiple emails can be separated by a comma or semicolon.
/// Watch out for <see cref="FormatException"/>s when enumerating.
/// </summary>
/// <param name="value">Collection of emails in the accepted formats.</param>
/// <returns>
/// A collection of <see cref="System.Net.Mail.MailAddress"/>es.
/// </returns>
/// <exception cref="ArgumentException">Thrown if the value is null, empty, or just whitespace.</exception>
public static IEnumerable<MailAddress> ExtractEmailAddresses(this string value)
{
if (string.IsNullOrWhiteSpace(value)) throw new ArgumentException("The arg cannot be null, empty, or just whitespace.", "value");
// Remove commas inside of quotes
value = value.Replace(';', ',');
var emails = value.SplitWhilePreservingQuotedValues(',');
var mailAddresses = emails.Select(email => new MailAddress(email));
return mailAddresses;
}
/// <summary>
/// Splits the string while preserving quoted values (i.e. instances of the delimiter character inside of quotes will not be split apart).
/// Trims leading and trailing whitespace from the individual string values.
/// Does not include empty values.
/// </summary>
/// <param name="value">The string to be split.</param>
/// <param name="delimiter">The delimiter to use to split the string, e.g. ',' for CSV.</param>
/// <returns>A collection of individual strings parsed from the original value.</returns>
public static IEnumerable<string> SplitWhilePreservingQuotedValues(this string value, char delimiter)
{
Regex csvPreservingQuotedStrings = new Regex(string.Format("(\"[^\"]*\"|[^{0}])+", delimiter));
var values =
csvPreservingQuotedStrings.Matches(value)
.Cast<Match>()
.Select(m => m.Value.Trim())
.Where(v => !string.IsNullOrWhiteSpace(v));
return values;
}
This method passes the following tests: 此方法通过以下测试:
[TestMethod]
public void ExtractEmails_SingleEmail_Matches()
{
string value = "a@a.a";
var expected = new List<MailAddress>
{
new MailAddress("a@a.a"),
};
var actual = value.ExtractEmailAddresses();
CollectionAssert.AreEqual(expected, actual.ToList());
}
[TestMethod()]
public void ExtractEmails_JustEmailCSV_Matches()
{
string value = "a@a.a; a@a.a";
var expected = new List<MailAddress>
{
new MailAddress("a@a.a"),
new MailAddress("a@a.a"),
};
var actual = value.ExtractEmailAddresses();
CollectionAssert.AreEqual(expected, actual.ToList());
}
[TestMethod]
public void ExtractEmails_MultipleWordNameThenEmailSemicolonSV_Matches()
{
string value = "a a a <a@a.a>; a a a <a@a.a>";
var expected = new List<MailAddress>
{
new MailAddress("a a a <a@a.a>"),
new MailAddress("a a a <a@a.a>"),
};
var actual = value.ExtractEmailAddresses();
CollectionAssert.AreEqual(expected, actual.ToList());
}
[TestMethod]
public void ExtractEmails_JustEmailsSemicolonSV_Matches()
{
string value = "a@a.a; a@a.a";
var expected = new List<MailAddress>
{
new MailAddress("a@a.a"),
new MailAddress("a@a.a"),
};
var actual = value.ExtractEmailAddresses();
CollectionAssert.AreEqual(expected, actual.ToList());
}
[TestMethod]
public void ExtractEmails_NameInQuotesWithCommaThenEmailsCSV_Matches()
{
string value = "\"a, a\" <a@a.a>; \"a, a\" <a@a.a>";
var expected = new List<MailAddress>
{
new MailAddress("\"a, a\" <a@a.a>"),
new MailAddress("\"a, a\" <a@a.a>"),
};
var actual = value.ExtractEmailAddresses();
CollectionAssert.AreEqual(expected, actual.ToList());
}
[TestMethod]
[ExpectedException(typeof(ArgumentException))]
public void ExtractEmails_EmptyString_Throws()
{
string value = string.Empty;
var actual = value.ExtractEmailAddresses();
}
[TestMethod]
[ExpectedException(typeof(FormatException))]
public void ExtractEmails_NonEmailValue_ThrowsOnEnumeration()
{
string value = "a";
var actual = value.ExtractEmailAddresses();
actual.ToList();
}
Actually, MailAddressCollection DOES support comma-delimited addresses, even with the commas inside the quotes. 实际上,MailAddressCollection DOES支持逗号分隔的地址,即使引号内有逗号也是如此。 The real problem I recently discovered , is that the CSV list must already be encoded into the ASCII character set, ie.
我最近发现的真正问题是,CSV列表必须已经编码为ASCII字符集,即。 Q-encoded or B-encoded for Unicode addresses.
针对Unicode地址进行Q编码或B编码。
There is no function in the base class libraries to perform this encoding, although I provide B-encoding in Sasa . 虽然我在Sasa中提供B编码,但基类库中没有执行此编码的功能。 I also just added an e-mail parsing function which addresses the question in this thread.
我还刚刚添加了一个电子邮件解析函数来解决这个问题。
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