[net7.0] Fix e-mail URI escaping recipients (#15244)

* Fix e-mail URI escaping recipients Escaping the recipient e-mail addresses, leads to the character @ being escaped and creates an invalid URL * Create proper RFC 2368 mailto url * Add unit tests * Optimize check if any items are present in collection --------- Co-authored-by: Tomasz Cielecki <tci@trackman.com>
dotnet · May 30, 2023 · a2bf5b8 · a2bf5b8
1 parent 7c1f069
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diff --git a/src/Essentials/src/Email/Email.shared.cs b/src/Essentials/src/Email/Email.shared.cs
@@ -60,31 +60,29 @@ public Task ComposeAsync(EmailMessage? message)
 			return PlatformComposeAsync(message);
 		}
 
-		static string GetMailToUri(EmailMessage message)
-		{
-			if (message != null && message.BodyFormat != EmailBodyFormat.PlainText)
-				throw new FeatureNotSupportedException("Only EmailBodyFormat.PlainText is supported if no email account is set up.");
+		internal static string GetMailToUri(EmailMessage message) =>
+			"mailto:?" + string.Join("&", Parameters(message));
 
-			var parts = new List<string>();
-			if (!string.IsNullOrEmpty(message?.Body))
-				parts.Add("body=" + Uri.EscapeDataString(message!.Body));
-			if (!string.IsNullOrEmpty(message?.Subject))
-				parts.Add("subject=" + Uri.EscapeDataString(message!.Subject));
-			if (message?.Cc?.Count > 0)
-				parts.Add("cc=" + Uri.EscapeDataString(string.Join(",", message.Cc)));
-			if (message?.Bcc?.Count > 0)
-				parts.Add("bcc=" + Uri.EscapeDataString(string.Join(",", message.Bcc)));
+		static IEnumerable<string> Parameters(EmailMessage message)
+		{
+			if (message.To?.Count > 0)
+				yield return "to=" + Recipients(message.To);
 
-			var uri = "mailto:";
+			if (message.Cc?.Count > 0)
+				yield return "cc=" + Recipients(message.Cc);
 
-			if (message?.To?.Count > 0)
-				uri += Uri.EscapeDataString(string.Join(",", message.To));
+			if (message.Bcc?.Count > 0)
+				yield return "bcc=" + Recipients(message.Bcc);
 
-			if (parts.Count > 0)
-				uri += "?" + string.Join("&", parts);
+			if (!string.IsNullOrWhiteSpace(message.Subject))
+				yield return "subject=" + Uri.EscapeDataString(message.Subject);
 
-			return uri;
+			if (!string.IsNullOrWhiteSpace(message.Body))
+				yield return "body=" + Uri.EscapeDataString(message.Body);
 		}
+
+		static string Recipients(IEnumerable<string> addresses) =>
+			string.Join(",", addresses.Select(Uri.EscapeDataString));
 	}
 
 	/// <summary>

diff --git a/src/Essentials/test/UnitTests/Email_Tests.cs b/src/Essentials/test/UnitTests/Email_Tests.cs
@@ -1,8 +1,195 @@
+using System;
+using System.Collections.Generic;
+using Microsoft.Maui.ApplicationModel.Communication;
 using Xunit;
 
 namespace Tests
 {
+	public class EmailDataGenerator : IEnumerable<object[]>
+	{
+		private readonly List<object[]> _data = new()
+		{
+			// empty
+			new object[]
+			{
+				new EmailMessage(),
+				"mailto:?"
+			},
+
+			// body only
+			new object[]
+			{
+				new EmailMessage { Body = "Hello" },
+				"mailto:?body=Hello"
+			},
+
+			// subject only
+			new object[]
+			{
+				new EmailMessage { Subject = "Hello" },
+				"mailto:?subject=Hello"
+			},
+
+			// subject and body
+			new object[]
+			{
+				new EmailMessage { Subject = "Hello", Body = "Yo" },
+				"mailto:?subject=Hello&body=Yo"
+			},
+
+			// to only
+			new object[]
+			{
+				new EmailMessage { To = new List<string> { "john@doe.net" } },
+				"mailto:?to=john%40doe.net"
+			},
+
+			// cc only
+			new object[]
+			{
+				new EmailMessage { Cc = new List<string> { "john@doe.net" } },
+				"mailto:?cc=john%40doe.net"
+			},
+
+			// bcc only
+			new object[]
+			{
+				new EmailMessage { Bcc = new List<string> { "john@doe.net" } },
+				"mailto:?bcc=john%40doe.net"
+			},
+
+			// To 1 recipient
+			new object[]
+			{
+				new EmailMessage
+				{
+					To = new List<string> { "sauron@mordor.gov.middleearth" },
+					Subject = "Claim your free rings of power",
+					Body = "Click this link to get your rings..."
+				},
+				"mailto:?to=sauron%40mordor.gov.middleearth&subject=Claim%20your%20free%20rings%20of%20power&body=Click%20this%20link%20to%20get%20your%20rings..."
+			},
+
+			// To 2 recipients
+			new object[]
+			{
+				new EmailMessage
+				{
+					To = new List<string> { "bilbo@hobbiton.shire", "frodo@hobbiton.shire" },
+					Subject = "Greetings",
+					Body = "Greetings Hobbits!"
+				},
+				"mailto:?to=bilbo%40hobbiton.shire,frodo%40hobbiton.shire&subject=Greetings&body=Greetings%20Hobbits%21"
+			},
+
+			// Cc 1 recipient
+			new object[]
+			{
+				new EmailMessage
+				{
+					Cc = new List<string> { "surfer@maui.net" },
+					Subject = "Big waves",
+					Body = "Dude, there were huge waves yesterday"
+				},
+				"mailto:?cc=surfer%40maui.net&subject=Big%20waves&body=Dude%2C%20there%20were%20huge%20waves%20yesterday"
+			},
+
+			// Cc 2 recipients
+			new object[]
+			{
+				new EmailMessage
+				{
+					Cc = new List<string> { "surfer@maui.net", "dude@surf.net" },
+					Subject = "Duuuude",
+					Body = "Sweet"
+				},
+				"mailto:?cc=surfer%40maui.net,dude%40surf.net&subject=Duuuude&body=Sweet"
+			},
+
+			// Bcc 1 recipient
+			new object[]
+			{
+				new EmailMessage
+				{
+					Bcc = new List<string> { "knights@who.say.ni" },
+					Subject = "Shrubberies here!",
+					Body = "Ekke Ekke Ekke Ekke Ptang Zoo Boing!"
+				},
+				"mailto:?bcc=knights%40who.say.ni&subject=Shrubberies%20here%21&body=Ekke%20Ekke%20Ekke%20Ekke%20Ptang%20Zoo%20Boing%21"
+			},
+
+			// Bcc 2 recipients
+			new object[]
+			{
+				new EmailMessage
+				{
+					Bcc = new List<string> { "knights@who.say.ni", "arthur@who.says.nu"
+					},
+					Subject = "Shrubberies here!",
+					Body = "Ekke Ekke Ekke Ekke Ptang Zoo Boing!"
+				},
+				"mailto:?bcc=knights%40who.say.ni,arthur%40who.says.nu&subject=Shrubberies%20here%21&body=Ekke%20Ekke%20Ekke%20Ekke%20Ptang%20Zoo%20Boing%21"
+			},
+
+			// Mixed recipients
+			new object[]
+			{
+				new EmailMessage
+				{
+					To = new List<string> { "bilbo@hobbiton.shire", "frodo@hobbiton.shire" },
+					Cc = new List<string> { "knights@who.say.ni", "arthur@who.says.nu" },
+					Subject = "Greetings", Body = "Greetings Hobbits!"
+				},
+				"mailto:?to=bilbo%40hobbiton.shire,frodo%40hobbiton.shire&cc=knights%40who.say.ni,arthur%40who.says.nu&subject=Greetings&body=Greetings%20Hobbits%21"
+			},
+		};
+
+		public IEnumerator<object[]> GetEnumerator() => _data.GetEnumerator();
+
+		System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator() => GetEnumerator();
+	}
+
 	public class Email_Tests
 	{
+		[Theory]
+		[ClassData(typeof(EmailDataGenerator))]
+		public void GetMailToUri_Returns_RFC2368_Valid_Url(EmailMessage message, string expectedUrl)
+		{
+			var result = EmailImplementation.GetMailToUri(message);
+
+			Assert.Equal(expectedUrl, result);
+		}
+
+		[Fact]
+		public void GetMailToUri_Ignores_Attachments()
+		{
+			var message = new EmailMessage
+			{
+				To = new List<string> { "mom@maui.net" },
+				Attachments = new List<EmailAttachment>
+				{
+					new EmailAttachment("/my/lovely/path/selfie.jpeg")
+				}
+			};
+
+			var result = EmailImplementation.GetMailToUri(message);
+
+			Assert.DoesNotContain("selfie", result, StringComparison.InvariantCultureIgnoreCase);
+		}
+
+		[Fact]
+		public void GetMailToUri_Ingores_BodyFormat()
+		{
+			var message = new EmailMessage
+			{
+				To = new List<string> { "mom@maui.net" },
+				BodyFormat = EmailBodyFormat.Html,
+				Body = "Hi Mom!"
+			};
+
+			var result = EmailImplementation.GetMailToUri(message);
+
+			Assert.Contains("Hi%20Mom%21", result, StringComparison.InvariantCulture);
+		}
 	}
 }