EscapeHtml PoC

src/libraries/Microsoft.PowerFx.Core/Localization/Strings.cs

@@ -518,6 +518,9 @@ internal static class TexlStrings
         public static StringGetter AboutEncodeUrl = (b) => StringResources.Get("AboutEncodeUrl", b);
         public static StringGetter EncodeUrlArg1 = (b) => StringResources.Get("EncodeUrlArg1", b);
 
+        public static StringGetter AboutEscapeHtml = (b) => StringResources.Get("AboutEscapeHtml", b);
+        public static StringGetter EscapeHtmlArg1 = (b) => StringResources.Get("EscapeHtmlArg1", b);
+
         public static StringGetter AboutPlainText = (b) => StringResources.Get("AboutPlainText", b);
         public static StringGetter PlainTextArg1 = (b) => StringResources.Get("PlainTextArg1", b);
 

src/libraries/Microsoft.PowerFx.Core/Texl/BuiltinFunctionsCore.cs

@@ -97,6 +97,7 @@ internal class BuiltinFunctionsCore
         public static readonly TexlFunction EncodeUrl = _library.Add(new EncodeUrlFunction());
         public static readonly TexlFunction EndsWith = _library.Add(new EndsWithFunction());
         public static readonly TexlFunction Error = _library.Add(new ErrorFunction());
+        public static readonly TexlFunction EscapeHtml = _library.Add(new EscapeHtmlFunction());
         public static readonly TexlFunction Exp = _library.Add(new ExpFunction());
         public static readonly TexlFunction ExpT = _library.Add(new ExpTableFunction());
         public static readonly TexlFunction Filter = _library.Add(new FilterFunction());

src/libraries/Microsoft.PowerFx.Core/Texl/Builtins/EscapeHtml.cs

@@ -0,0 +1,23 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+using System.Collections.Generic;
+using Microsoft.PowerFx.Core.Localization;
+using Microsoft.PowerFx.Core.Texl.Builtins;
+using Microsoft.PowerFx.Core.Types;
+
+namespace Microsoft.PowerFx.Core.Texl
+{
+    internal sealed class EscapeHtmlFunction : StringOneArgFunction
+    {
+    public EscapeHtmlFunction()
+            : base("EscapeHtml", TexlStrings.AboutEscapeHtml, FunctionCategories.Text)
+        { 
+        }
+
+    public override IEnumerable<TexlStrings.StringGetter[]> GetSignatures()
+        {
+            yield return new[] { TexlStrings.EscapeHtmlArg1 };
+        }
+    }
+}

src/libraries/Microsoft.PowerFx.Interpreter/Functions/Library.cs

@@ -674,6 +674,17 @@ static Library()
                     returnBehavior: ReturnBehavior.ReturnFalseIfAnyArgIsBlank,
                     targetFunction: Error)
             },
+            {
+                BuiltinFunctionsCore.EscapeHtml,
+                StandardErrorHandling<StringValue>(
+                    BuiltinFunctionsCore.EncodeUrl.Name,
+                    expandArguments: NoArgExpansion,
+                    replaceBlankValues: NoOpAlreadyHandledByIR,
+                    checkRuntimeTypes: ExactValueType<StringValue>,
+                    checkRuntimeValues: DeferRuntimeValueChecking,
+                    returnBehavior: ReturnBehavior.AlwaysEvaluateAndReturnResult,
+                    targetFunction: EscapeHtml)
+            },
             {
                 BuiltinFunctionsCore.Exp,
                 StandardErrorHandling<NumberValue>(

src/libraries/Microsoft.PowerFx.Interpreter/Functions/LibraryText.cs

@@ -11,6 +11,7 @@
 using System.Text.RegularExpressions;
 using System.Threading;
 using System.Threading.Tasks;
+using System.Web;
 using Microsoft.PowerFx.Core.IR;
 using Microsoft.PowerFx.Core.Localization;
 using Microsoft.PowerFx.Core.Utils;
@@ -801,6 +802,12 @@ public static FormulaValue EncodeUrl(IRContext irContext, StringValue[] args)
             return new StringValue(irContext, Uri.EscapeDataString(args[0].Value));
         }
 
+        public static FormulaValue EscapeHtml(IRContext irContext, StringValue[] args)
+        {
+            var encoded = HttpUtility.HtmlEncode(args[0].Value);
+            return new StringValue(irContext, encoded);
+        }
+
         public static FormulaValue Proper(EvalVisitor runner, EvalVisitorContext context, IRContext irContext, StringValue[] args)
         {
             return new StringValue(irContext, runner.CultureInfo.TextInfo.ToTitleCase(runner.CultureInfo.TextInfo.ToLower(args[0].Value)));

src/strings/PowerFxResources.en-US.resx

@@ -4092,6 +4092,17 @@
   <data name="AboutEncodeUrl_url" xml:space="preserve">
     <value>A url to be encoded.</value>
   </data>
+  <data name="AboutEscapeHtml" xml:space="preserve">
+    <value>Converts a text to an HTML-encoded text.</value>
+    <comment>Description of 'EncodeUrl' function.</comment>
+  </data>
+  <data name="EscapeHtmlArg1" xml:space="preserve">
+    <value>value</value>
+    <comment>Function_parameter - First parameter for the EscapeHtml function - the value (string) to escape.</comment>
+  </data>
+  <data name="AboutEscapeHtml_value" xml:space="preserve">
+    <value>A text to be escaped.</value>
+  </data>
   <data name="ErrUnimplementedFunction" xml:space="preserve">
     <value>'{0}' is a recognized but not supported function.</value>
     <comment>Error Message.</comment>

src/tests/Microsoft.PowerFx.Core.Tests/ExpressionTestCases/EscapeHtml.txt

@@ -0,0 +1,42 @@
+// Escaping
+>> EscapeHtml("<p>A paragraph</p>")
+"&lt;p&gt;A paragraph&lt;/p&gt;"
+
+// Multiple encodings
+>> EscapeHtml("<h1>Mac & cheese</h1>")
+"&lt;h1&gt;Mac &amp; cheese&lt;/h1&gt;"
+
+// Quotes
+>> EscapeHtml("A value with ""double"" and 'single' quotes")
+"A value with &quot;double&quot; and &#39;single&#39; quotes"
+
+// \u00A0 to \u00af - escaped
+>> EscapeHtml(Concat(Sequence(16, 160), UniChar(Value)))
+"&#160;&#161;&#162;&#163;&#164;&#165;&#166;&#167;&#168;&#169;&#170;&#171;&#172;&#173;&#174;&#175;"
+
+// \u0090 to \u009f - not escaped
+>> With({str:Concat(Sequence(16, 144), UniChar(Value))}, str = EscapeHtml(str))
+true
+
+// \u00A0 to \u00ff - escaped
+>> With({str:EscapeHtml(Concat(Sequence(96, 160), UniChar(Value))), expectedEscaped:Concat(Sequence(96, 160), $"&#{Value};")}, str = expectedEscaped)
+true
+
+// \u0100... not escaped
+>> EscapeHtml("<b>ĀāĂă</b>")
+"&lt;b&gt;ĀāĂă&lt;/b&gt;"
+
+// Blanks
+>> EscapeHtml(Blank())
+""
+
+// Errors
+>> EscapeHtml(Char(-1))
+Error({Kind:ErrorKind.InvalidArgument})
+
+// Escaping surrogate pairs
+>> EscapeHtml("<ul><li>not a pair: ❤</li><li>a surrogate pair: 💩</li></ul>")
+"&lt;ul&gt;&lt;li&gt;not a pair: ❤&lt;/li&gt;&lt;li&gt;a surrogate pair: &#128169;&lt;/li&gt;&lt;/ul&gt;"
+
+>> EscapeHtml("Osage alphabet (start): 𐒰𐒱𐒲𐒳𐒴𐒵𐒶")
+"Osage alphabet (start): &#66736;&#66737;&#66738;&#66739;&#66740;&#66741;&#66742;"

src/tests/Microsoft.PowerFx.Interpreter.Tests/Docs/InterpreterBase.json

@@ -50,6 +50,7 @@
     "EndsWith",
     "EOMonth",
     "Error",
+    "EscapeHtml",
     "Exp",
     "Filter",
     "Find",