Allow mailto scheme in inline links

Author: reakaleek

src/Elastic.Markdown/Myst/InlineParsers/DiagnosticLinkInlineParser.cs

@@ -138,7 +138,10 @@ private bool ValidateBasicUrl(InlineProcessor processor, string? url, int line,
 
 	private bool ValidateExternalUri(InlineProcessor processor, Uri? uri, ParserContext context, int line, int column, int length)
 	{
-		if (uri == null || !uri.Scheme.StartsWith("http"))
+		if (uri == null)
+			return false;
+
+		if (!uri.Scheme.StartsWith("http") && !uri.Scheme.StartsWith("mailto"))
 			return false;
 
 		var baseDomain = uri.Host == "localhost" ? "localhost" : string.Join('.', uri.Host.Split('.')[^2..]);

tests/authoring/Framework/ErrorCollectorAssertions.fs

@@ -29,6 +29,11 @@ module DiagnosticsCollectorAssertions =
                                    |> List.ofArray
         let message = errorDiagnostics.FirstOrDefault().Message
         test <@ message.Contains(expected) @>
+        
+    let hasNoWarnings (actual: Lazy<GeneratorResults>) =
+        let actual = actual.Value
+        let warnings = actual.Context.Collector.Warnings
+        test <@ warnings = 0 @>
 
     [<DebuggerStepThrough>]
     let hasWarning (expected: string) (actual: Lazy<GeneratorResults>) =

tests/authoring/Framework/Setup.fs

@@ -120,4 +120,3 @@ type Setup =
             task { return! Setup.Generator [Index m] }
             |> Async.AwaitTask |> Async.RunSynchronously
         )
-

tests/authoring/Inline/InlineLinks.fs

@@ -0,0 +1,48 @@
+// Licensed to Elasticsearch B.V under one or more agreements.
+// Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
+// See the LICENSE file in the project root for more information
+
+module ``inline elements``.``links``
+
+open Xunit
+open authoring
+
+type ``inline link with mailto`` () =
+
+    static let markdown = Setup.Markdown """
+[email me](mailto:[email protected])
+"""
+
+    [<Fact>]
+    let ``validate HTML`` () =
+        markdown |> convertsToHtml """
+            <p>
+	            <a href="mailto:[email protected]">email me</a>
+            </p>
+        """
+        
+    [<Fact>]
+    let ``has no errors`` () = markdown |> hasNoErrors
+
+    [<Fact>]
+    let ``has no warning`` () = markdown |> hasNoWarnings
+
+type ``inline link with mailto not allowed external host`` () =
+
+    static let markdown = Setup.Markdown """
+[email me](mailto:[email protected])
+"""
+
+    [<Fact>]
+    let ``validate HTML`` () =
+        markdown |> convertsToHtml """
+            <p>
+	            <a href="mailto:[email protected]">email me</a>
+            </p>
+        """
+        
+    [<Fact>]
+    let ``has no errors`` () = markdown |> hasNoErrors
+
+    [<Fact>]
+    let ``has warning`` () = markdown |> hasWarning "External URI 'mailto:[email protected]' is not allowed."

tests/authoring/authoring.fsproj

@@ -47,6 +47,7 @@
   </ItemGroup>
 
   <ItemGroup>
+    <Compile Include="Inline\InlineLinks.fs" />
     <Compile Include="Container\DefinitionLists.fs"/>
     <Compile Include="Generator\LinkReferenceFile.fs"/>
   </ItemGroup>