Added support for ignoring integrity attribute on fallback for the Link TagHelper

- Do not include integrity attribute when asp-fallback-intergrity-check is false
 - Added Unit Tests, manual tests

Addresses #7845

src/Microsoft.AspNetCore.Mvc.TagHelpers/LinkTagHelper.cs

@@ -25,6 +25,7 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
     [HtmlTargetElement("link", Attributes = HrefIncludeAttributeName, TagStructure = TagStructure.WithoutEndTag)]
     [HtmlTargetElement("link", Attributes = HrefExcludeAttributeName, TagStructure = TagStructure.WithoutEndTag)]
     [HtmlTargetElement("link", Attributes = FallbackHrefAttributeName, TagStructure = TagStructure.WithoutEndTag)]
+    [HtmlTargetElement("link", Attributes = FallbackHrefIntegrityCheckAttributeName, TagStructure = TagStructure.WithoutEndTag)]
     [HtmlTargetElement("link", Attributes = FallbackHrefIncludeAttributeName, TagStructure = TagStructure.WithoutEndTag)]
     [HtmlTargetElement("link", Attributes = FallbackHrefExcludeAttributeName, TagStructure = TagStructure.WithoutEndTag)]
     [HtmlTargetElement("link", Attributes = FallbackTestClassAttributeName, TagStructure = TagStructure.WithoutEndTag)]
@@ -40,6 +41,7 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
         private const string HrefIncludeAttributeName = "asp-href-include";
         private const string HrefExcludeAttributeName = "asp-href-exclude";
         private const string FallbackHrefAttributeName = "asp-fallback-href";
+        private const string FallbackHrefIntegrityCheckAttributeName = "asp-fallback-href-integrity-check";
         private const string FallbackHrefIncludeAttributeName = "asp-fallback-href-include";
         private const string FallbackHrefExcludeAttributeName = "asp-fallback-href-exclude";
         private const string FallbackTestClassAttributeName = "asp-fallback-test-class";
@@ -147,6 +149,14 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
         [HtmlAttributeName(FallbackHrefAttributeName)]
         public string FallbackHref { get; set; }
 
+        /// <summary>
+        /// Boolean value that determines if Integrity Hash will be compared with <see cref="FallbackHref"/> value.
+        /// Value defaults to true if not provided. 
+        /// Must be used in conjunction with <see cref="FallbackHref"/>.
+        /// </summary>
+        [HtmlAttributeName(FallbackHrefIntegrityCheckAttributeName)]
+        public bool? FallbackHrefIntegrityCheck { get; set; }
+
         /// <summary>
         /// Value indicating if file version should be appended to the href urls.
         /// </summary>
@@ -367,6 +377,12 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
                     continue;
                 }
 
+                // do not write integrity attribute when FallbackHrefIntegrityCheck is false
+                if (attribute.Name.Equals("integrity", StringComparison.OrdinalIgnoreCase) && FallbackHrefIntegrityCheck == false)
+                {
+                    continue;
+                }
+
                 attribute.WriteTo(StringWriter, HtmlEncoder);
                 StringWriter.Write(' ');
             }

src/Microsoft.AspNetCore.Mvc.TagHelpers/ScriptTagHelper.cs

@@ -27,6 +27,7 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
     [HtmlTargetElement("script", Attributes = FallbackSrcIncludeAttributeName)]
     [HtmlTargetElement("script", Attributes = FallbackSrcExcludeAttributeName)]
     [HtmlTargetElement("script", Attributes = FallbackTestExpressionAttributeName)]
+    [HtmlTargetElement("script", Attributes = FallbackIntegrityCheckAttributeName)]
     [HtmlTargetElement("script", Attributes = AppendVersionAttributeName)]
     public class ScriptTagHelper : UrlResolutionTagHelper
     {
@@ -34,6 +35,7 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
         private const string SrcExcludeAttributeName = "asp-src-exclude";
         private const string FallbackSrcAttributeName = "asp-fallback-src";
         private const string FallbackSrcIncludeAttributeName = "asp-fallback-src-include";
+        private const string FallbackIntegrityCheckAttributeName = "asp-fallback-integrity-check";
         private const string FallbackSrcExcludeAttributeName = "asp-fallback-src-exclude";
         private const string FallbackTestExpressionAttributeName = "asp-fallback-test";
         private const string SrcAttributeName = "src";
@@ -129,6 +131,14 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
         [HtmlAttributeName(FallbackSrcAttributeName)]
         public string FallbackSrc { get; set; }
 
+        /// <summary>
+        /// Boolean value that determines if Integrity Hash will be compared with <see cref="FallbackSrc"/> value.
+        /// Value defaults to true if not provided. 
+        /// Must be used in conjunction with <see cref="FallbackSrc"/>.
+        /// </summary>
+        [HtmlAttributeName(FallbackIntegrityCheckAttributeName)]
+        public bool? FallbackIntegrityCheck { get; set; }
+
         /// <summary>
         /// Value indicating if file version should be appended to src urls.
         /// </summary>
@@ -312,6 +322,9 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
                         var attribute = attributes[i];
                         if (!attribute.Name.Equals(SrcAttributeName, StringComparison.OrdinalIgnoreCase))
                         {
+                            // do not write integrity attribute when fallbackintegrityCheck is false
+                            if (attribute.Name.Equals("integrity", StringComparison.OrdinalIgnoreCase) && FallbackIntegrityCheck == false) continue;
+
                             StringWriter.Write(' ');
                             attribute.WriteTo(StringWriter, HtmlEncoder);
                         }

test/Microsoft.AspNetCore.Mvc.FunctionalTests/compiler/resources/HtmlGenerationWebSite.HtmlGeneration_Home.Script.Encoded.html

@@ -19,11 +19,27 @@
         // Fallback to globbed src
     </script>
 <script>(false||document.write("JavaScriptEncode[[<script src="HtmlEncode[[/styles/site.js]]" title='"the" title'></script>]]"));</script>
+    
+    <script src="HtmlEncode[[/styles/siteIntegrity.js?a=integrity]]" crossorigin="anonymous" integrity="sha256-tMQLOHBNPE829MHQPO8metegsGobA/henDPOvtZOWhQ=">
+       // Script loading primary source, applied integrity hash to primary source.
+    </script>
+<script>(true||document.write("JavaScriptEncode[[<script src="HtmlEncode[[/styles/sub/site2.js?a=integrity]]" crossorigin="anonymous" integrity="sha256-tMQLOHBNPE829MHQPO8metegsGobA/henDPOvtZOWhQ="></script>]]"));</script>
+
+    <script src="HtmlEncode[[/styles/siteIntegrity.js?a=integrity]]" crossorigin="anonymous" integrity="sha256-tMQLOHBNPE829MHQPO8metegsGobA/henDPOvtZOWhQ=">
+
+       // Script uses fallback source, applies integrity hash to fallback.
+    </script>
+<script>(false||document.write("JavaScriptEncode[[<script src="HtmlEncode[[/styles/sub/siteIntegrity2.js?a=integrity]]" crossorigin="anonymous" integrity="sha256-tMQLOHBNPE829MHQPO8metegsGobA/henDPOvtZOWhQ="></script>]]"));</script>
+
+    <script src="HtmlEncode[[/styles/siteIntegrity.js?a=integrity]]" crossorigin="anonymous" integrity="sha256-tMQLOHBNPE829MHQPO8metegsGobA/henDPOvtZOWhQ=">
+       // Script uses fallback source, ignores integrity hash on fallback.
+    </script>
+<script>(false||document.write("JavaScriptEncode[[<script src="HtmlEncode[[/styles/sub/siteIntegrity3.js?a=integrity]]" crossorigin="anonymous"></script>]]"));</script>
 
     <script src="HtmlEncode[[/blank.js]]">
         // Fallback to globbed src with exclude
     </script>
-<script>(false||document.write("JavaScriptEncode[[<script src="HtmlEncode[[/styles/site.js]]"></script><script src="HtmlEncode[[/styles/sub/site2.js]]"></script>]]"));</script>
+<script>(false||document.write("JavaScriptEncode[[<script src="HtmlEncode[[/styles/site.js]]"></script><script src="HtmlEncode[[/styles/siteIntegrity.js]]"></script><script src="HtmlEncode[[/styles/sub/site2.js]]"></script><script src="HtmlEncode[[/styles/sub/siteIntegrity2.js]]"></script><script src="HtmlEncode[[/styles/sub/siteIntegrity3.js]]"></script>]]"));</script>
 
     <script src="HtmlEncode[[/blank.js]]">
         // Fallback to globbed and static src
@@ -65,7 +81,7 @@
     <script src="HtmlEncode[[/styles/site.js]]"></script>
 
     <!-- Globbed script tag with existing file and exclude -->
-    <script src="HtmlEncode[[/styles/site.js]]"></script><script src="HtmlEncode[[/styles/sub/site2.js]]"></script>
+    <script src="HtmlEncode[[/styles/site.js]]"></script><script src="HtmlEncode[[/styles/siteIntegrity.js]]"></script><script src="HtmlEncode[[/styles/sub/site2.js]]"></script><script src="HtmlEncode[[/styles/sub/siteIntegrity2.js]]"></script><script src="HtmlEncode[[/styles/sub/siteIntegrity3.js]]"></script>
 
     <script>
         // Globbed script tag missing include
@@ -76,7 +92,7 @@
     </script>
 
     <!-- Globbed script tag with comma separated include pattern -->
-    <script src="HtmlEncode[[/styles/site.js]]"></script><script src="HtmlEncode[[/styles/sub/site2.js]]"></script><script src="HtmlEncode[[/styles/sub/site3.js]]"></script>
+    <script src="HtmlEncode[[/styles/site.js]]"></script><script src="HtmlEncode[[/styles/siteIntegrity.js]]"></script><script src="HtmlEncode[[/styles/sub/site2.js]]"></script><script src="HtmlEncode[[/styles/sub/site3.js]]"></script><script src="HtmlEncode[[/styles/sub/siteIntegrity2.js]]"></script><script src="HtmlEncode[[/styles/sub/siteIntegrity3.js]]"></script>
 
     <!-- Globbed script tag with missing file -->
     
@@ -110,9 +126,9 @@
     </script>
 
     <!-- Globbed script tag with existing files and version -->
-    <script src="HtmlEncode[[/styles/site.js?v=jx1PJjLX32-xgQQx2BxnckU9QH9DVKkm4-M5bSK869I]]"></script><script src="HtmlEncode[[/styles/sub/site2.js?v=pwJaxaQxnb-rPAdF2JlAp4xiPNq1XuJFd6TyOOfNF-0]]"></script><script src="HtmlEncode[[/styles/sub/site3.js?v=lmeAMiqm76lnGyqHhu6PIBHAC0Vt46mgVB_KaG_gGdA]]"></script>
+    <script src="HtmlEncode[[/styles/site.js?v=jx1PJjLX32-xgQQx2BxnckU9QH9DVKkm4-M5bSK869I]]"></script><script src="HtmlEncode[[/styles/siteIntegrity.js?v=tMQLOHBNPE829MHQPO8metegsGobA_henDPOvtZOWhQ]]"></script><script src="HtmlEncode[[/styles/sub/site2.js?v=pwJaxaQxnb-rPAdF2JlAp4xiPNq1XuJFd6TyOOfNF-0]]"></script><script src="HtmlEncode[[/styles/sub/site3.js?v=lmeAMiqm76lnGyqHhu6PIBHAC0Vt46mgVB_KaG_gGdA]]"></script><script src="HtmlEncode[[/styles/sub/siteIntegrity2.js?v=tMQLOHBNPE829MHQPO8metegsGobA_henDPOvtZOWhQ]]"></script><script src="HtmlEncode[[/styles/sub/siteIntegrity3.js?v=6I1ncApSzTYytACF7244bg3a_sEnKrGH8nVudoaN984]]"></script>
 
     <!-- Globbed script tag with existing file, exclude and version -->
-    <script src="HtmlEncode[[/styles/site.js?v=jx1PJjLX32-xgQQx2BxnckU9QH9DVKkm4-M5bSK869I]]"></script><script src="HtmlEncode[[/styles/sub/site2.js?v=pwJaxaQxnb-rPAdF2JlAp4xiPNq1XuJFd6TyOOfNF-0]]"></script>
+    <script src="HtmlEncode[[/styles/site.js?v=jx1PJjLX32-xgQQx2BxnckU9QH9DVKkm4-M5bSK869I]]"></script><script src="HtmlEncode[[/styles/siteIntegrity.js?v=tMQLOHBNPE829MHQPO8metegsGobA_henDPOvtZOWhQ]]"></script><script src="HtmlEncode[[/styles/sub/site2.js?v=pwJaxaQxnb-rPAdF2JlAp4xiPNq1XuJFd6TyOOfNF-0]]"></script><script src="HtmlEncode[[/styles/sub/siteIntegrity2.js?v=tMQLOHBNPE829MHQPO8metegsGobA_henDPOvtZOWhQ]]"></script><script src="HtmlEncode[[/styles/sub/siteIntegrity3.js?v=6I1ncApSzTYytACF7244bg3a_sEnKrGH8nVudoaN984]]"></script>
 </body>
 </html>

test/Microsoft.AspNetCore.Mvc.FunctionalTests/compiler/resources/HtmlGenerationWebSite.HtmlGeneration_Home.Script.html

@@ -19,11 +19,27 @@
         // Fallback to globbed src
     </script>
 <script>(false||document.write("\u003Cscript src=\u0022\/styles\/site.js\u0022 title=\u0027\u0022the\u0022 title\u0027\u003E\u003C\/script\u003E"));</script>
+    
+    <script src="/styles/siteIntegrity.js?a=integrity" crossorigin="anonymous" integrity="sha256-tMQLOHBNPE829MHQPO8metegsGobA/henDPOvtZOWhQ=">
+       // Script loading primary source, applied integrity hash to primary source.
+    </script>
+<script>(true||document.write("\u003Cscript src=\u0022\/styles\/sub\/site2.js?a=integrity\u0022 crossorigin=\u0022anonymous\u0022 integrity=\u0022sha256-tMQLOHBNPE829MHQPO8metegsGobA\/henDPOvtZOWhQ=\u0022\u003E\u003C\/script\u003E"));</script>
+
+    <script src="/styles/siteIntegrity.js?a=integrity" crossorigin="anonymous" integrity="sha256-tMQLOHBNPE829MHQPO8metegsGobA/henDPOvtZOWhQ=">
+
+       // Script uses fallback source, applies integrity hash to fallback.
+    </script>
+<script>(false||document.write("\u003Cscript src=\u0022\/styles\/sub\/siteIntegrity2.js?a=integrity\u0022 crossorigin=\u0022anonymous\u0022 integrity=\u0022sha256-tMQLOHBNPE829MHQPO8metegsGobA\/henDPOvtZOWhQ=\u0022\u003E\u003C\/script\u003E"));</script>
+
+    <script src="/styles/siteIntegrity.js?a=integrity" crossorigin="anonymous" integrity="sha256-tMQLOHBNPE829MHQPO8metegsGobA/henDPOvtZOWhQ=">
+       // Script uses fallback source, ignores integrity hash on fallback.
+    </script>
+<script>(false||document.write("\u003Cscript src=\u0022\/styles\/sub\/siteIntegrity3.js?a=integrity\u0022 crossorigin=\u0022anonymous\u0022\u003E\u003C\/script\u003E"));</script>
 
     <script src="/blank.js">
         // Fallback to globbed src with exclude
     </script>
-<script>(false||document.write("\u003Cscript src=\u0022\/styles\/site.js\u0022\u003E\u003C\/script\u003E\u003Cscript src=\u0022\/styles\/sub\/site2.js\u0022\u003E\u003C\/script\u003E"));</script>
+<script>(false||document.write("\u003Cscript src=\u0022\/styles\/site.js\u0022\u003E\u003C\/script\u003E\u003Cscript src=\u0022\/styles\/siteIntegrity.js\u0022\u003E\u003C\/script\u003E\u003Cscript src=\u0022\/styles\/sub\/site2.js\u0022\u003E\u003C\/script\u003E\u003Cscript src=\u0022\/styles\/sub\/siteIntegrity2.js\u0022\u003E\u003C\/script\u003E\u003Cscript src=\u0022\/styles\/sub\/siteIntegrity3.js\u0022\u003E\u003C\/script\u003E"));</script>
 
     <script src="/blank.js">
         // Fallback to globbed and static src
@@ -65,7 +81,7 @@
     <script src="/styles/site.js"></script>
 
     <!-- Globbed script tag with existing file and exclude -->
-    <script src="/styles/site.js"></script><script src="/styles/sub/site2.js"></script>
+    <script src="/styles/site.js"></script><script src="/styles/siteIntegrity.js"></script><script src="/styles/sub/site2.js"></script><script src="/styles/sub/siteIntegrity2.js"></script><script src="/styles/sub/siteIntegrity3.js"></script>
 
     <script>
         // Globbed script tag missing include
@@ -76,7 +92,7 @@
     </script>
 
     <!-- Globbed script tag with comma separated include pattern -->
-    <script src="/styles/site.js"></script><script src="/styles/sub/site2.js"></script><script src="/styles/sub/site3.js"></script>
+    <script src="/styles/site.js"></script><script src="/styles/siteIntegrity.js"></script><script src="/styles/sub/site2.js"></script><script src="/styles/sub/site3.js"></script><script src="/styles/sub/siteIntegrity2.js"></script><script src="/styles/sub/siteIntegrity3.js"></script>
 
     <!-- Globbed script tag with missing file -->
     
@@ -110,9 +126,9 @@
     </script>
 
     <!-- Globbed script tag with existing files and version -->
-    <script src="/styles/site.js?v=jx1PJjLX32-xgQQx2BxnckU9QH9DVKkm4-M5bSK869I"></script><script src="/styles/sub/site2.js?v=pwJaxaQxnb-rPAdF2JlAp4xiPNq1XuJFd6TyOOfNF-0"></script><script src="/styles/sub/site3.js?v=lmeAMiqm76lnGyqHhu6PIBHAC0Vt46mgVB_KaG_gGdA"></script>
+    <script src="/styles/site.js?v=jx1PJjLX32-xgQQx2BxnckU9QH9DVKkm4-M5bSK869I"></script><script src="/styles/siteIntegrity.js?v=tMQLOHBNPE829MHQPO8metegsGobA_henDPOvtZOWhQ"></script><script src="/styles/sub/site2.js?v=pwJaxaQxnb-rPAdF2JlAp4xiPNq1XuJFd6TyOOfNF-0"></script><script src="/styles/sub/site3.js?v=lmeAMiqm76lnGyqHhu6PIBHAC0Vt46mgVB_KaG_gGdA"></script><script src="/styles/sub/siteIntegrity2.js?v=tMQLOHBNPE829MHQPO8metegsGobA_henDPOvtZOWhQ"></script><script src="/styles/sub/siteIntegrity3.js?v=6I1ncApSzTYytACF7244bg3a_sEnKrGH8nVudoaN984"></script>
 
     <!-- Globbed script tag with existing file, exclude and version -->
-    <script src="/styles/site.js?v=jx1PJjLX32-xgQQx2BxnckU9QH9DVKkm4-M5bSK869I"></script><script src="/styles/sub/site2.js?v=pwJaxaQxnb-rPAdF2JlAp4xiPNq1XuJFd6TyOOfNF-0"></script>
+    <script src="/styles/site.js?v=jx1PJjLX32-xgQQx2BxnckU9QH9DVKkm4-M5bSK869I"></script><script src="/styles/siteIntegrity.js?v=tMQLOHBNPE829MHQPO8metegsGobA_henDPOvtZOWhQ"></script><script src="/styles/sub/site2.js?v=pwJaxaQxnb-rPAdF2JlAp4xiPNq1XuJFd6TyOOfNF-0"></script><script src="/styles/sub/siteIntegrity2.js?v=tMQLOHBNPE829MHQPO8metegsGobA_henDPOvtZOWhQ"></script><script src="/styles/sub/siteIntegrity3.js?v=6I1ncApSzTYytACF7244bg3a_sEnKrGH8nVudoaN984"></script>
 </body>
 </html>

test/Microsoft.AspNetCore.Mvc.FunctionalTests/compiler/resources/RazorPagesWebSite.SimpleForms.html

@@ -3,5 +3,4 @@
 <form method="post"><input name="__RequestVerificationToken" type="hidden" value="{0}" /></form>
 <form action="" method="post"><input name="__RequestVerificationToken" type="hidden" value="{0}" /></form>
 <form action="/Foo/Bar/Baz.html" method="get"></form>
-<form action="/Foo/Bar/Baz.html" method="post"></form>
+<form action="/Foo/Bar/Baz.html" method="post"></form>
-<form action="/RedirectToPage" method="post"><input name="__RequestVerificationToken" type="hidden" value="{0}" /></form>

test/Microsoft.AspNetCore.Mvc.TagHelpers.Test/LinkTagHelperTest.cs

@@ -263,7 +263,49 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
                             tagHelper.FallbackTestValue = "hidden";
                             tagHelper.AppendVersion = true;
                         }
-                    }
+                    },
+                    // asp-fallback-href-integrity-check Attribute true
+                    {
+                        new TagHelperAttributeList
+                        {
+                            new TagHelperAttribute("asp-fallback-href", "test.css"),
+                            new TagHelperAttribute("asp-fallback-test-class", "hidden"),
+                            new TagHelperAttribute("asp-fallback-test-property", "visibility"),
+                            new TagHelperAttribute("asp-fallback-test-value", "hidden"),
+                            new TagHelperAttribute("asp-append-version", "true"),
+                            new TagHelperAttribute("asp-fallback-href-integrity-check", "true")
+                        },
+                        tagHelper =>
+                        {
+                            tagHelper.FallbackHref = "test.css";
+                            tagHelper.FallbackTestClass = "hidden";
+                            tagHelper.FallbackTestProperty = "visibility";
+                            tagHelper.FallbackTestValue = "hidden";
+                            tagHelper.AppendVersion = true;
+                            tagHelper.FallbackHrefIntegrityCheck = true;
+                        }
+                    },
+                    // asp-fallback-href-integrity-check Attribute false
+                    {
+                        new TagHelperAttributeList
+                        {
+                            new TagHelperAttribute("asp-fallback-href", "test.css"),
+                            new TagHelperAttribute("asp-fallback-test-class", "hidden"),
+                            new TagHelperAttribute("asp-fallback-test-property", "visibility"),
+                            new TagHelperAttribute("asp-fallback-test-value", "hidden"),
+                            new TagHelperAttribute("asp-append-version", "true"),
+                            new TagHelperAttribute("asp-fallback-href-integrity-check", "false")
+                        },
+                        tagHelper =>
+                        {
+                            tagHelper.FallbackHref = "test.css";
+                            tagHelper.FallbackTestClass = "hidden";
+                            tagHelper.FallbackTestProperty = "visibility";
+                            tagHelper.FallbackTestValue = "hidden";
+                            tagHelper.AppendVersion = true;
+                            tagHelper.FallbackHrefIntegrityCheck = false;
+                        }
+                    },
                 };
             }
         }

test/Microsoft.AspNetCore.Mvc.TagHelpers.Test/ScriptTagHelperTest.cs

@@ -156,6 +156,20 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
                             tagHelper.FallbackTestExpression = "isavailable()";
                         }
                     },
+                    {
+                        new TagHelperAttributeList
+                        {
+                            new TagHelperAttribute("asp-fallback-src", "test.js"),
+                            new TagHelperAttribute("asp-fallback-test", "isavailable()"),
+                            new TagHelperAttribute("asp-fallback-integrity-check", "false")
+                        },
+                        tagHelper =>
+                        {
+                            tagHelper.FallbackSrc = "test.js";
+                            tagHelper.FallbackTestExpression = "isavailable()";
+                            tagHelper.FallbackIntegrityCheck = false;
+                        }
+                    },
                     {
                         new TagHelperAttributeList
                         {
@@ -182,6 +196,22 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
                             tagHelper.FallbackTestExpression = "isavailable()";
                         }
                     },
+                    {
+                        new TagHelperAttributeList
+                        {
+                            new TagHelperAttribute("asp-fallback-src", "test.js"),
+                            new TagHelperAttribute("asp-fallback-src-include", "*.js"),
+                            new TagHelperAttribute("asp-fallback-test", "isavailable()"),
+                            new TagHelperAttribute("asp-fallback-integrity-check", "false")
+                        },
+                        tagHelper =>
+                        {
+                            tagHelper.FallbackSrc = "test.js";
+                            tagHelper.FallbackSrcInclude = "*.css";
+                            tagHelper.FallbackTestExpression = "isavailable()";
+                            tagHelper.FallbackIntegrityCheck = false;
+                        }
+                    },
                     {
                         new TagHelperAttributeList
                         {

test/WebSites/HtmlGenerationWebSite/Views/HtmlGeneration_Home/Link.cshtml

@@ -46,6 +46,35 @@
           asp-fallback-test-property="visibility"
           asp-fallback-test-value="hidden" />
 
+    <!-- Fallback to static href with no asp-fallback-href-integrity-check attribute, default behavior is to keep integrity hash -->
+    <link href="~/styles/site.min.css?a=b&c=d" rel="stylesheet" data-extra="test" title='"the" title'
+          integrity="XY7YsMemPf8AGU4SIX9ED9eOjK1LOQWu2dmCNmh+pQc="
+          crossorigin="anonymous"
+          asp-fallback-href="~/styles/site.css?a=b&c=d"
+          asp-fallback-test-class="hidden"
+          asp-fallback-test-property="visibility"
+          asp-fallback-test-value="hidden" />
+
+    <!-- Fallback to static href with asp-fallback-href-integrity-check set to true, default behavior is to keep integrity hash -->
+    <link href="~/styles/site.min.css?a=b&c=d" rel="stylesheet" data-extra="test" title='"the" title'
+          integrity="XY7YsMemPf8AGU4SIX9ED9eOjK1LOQWu2dmCNmh+pQc="
+          crossorigin="anonymous"
+          asp-fallback-href="~/styles/site.css?a=b&c=d"
+          asp-fallback-test-class="hidden"
+          asp-fallback-test-property="visibility"
+          asp-fallback-test-value="hidden"
+          asp-fallback-href-integrity-check="true" />
+
+    <!-- Fallback to static href with asp-fallback-href-integrity-check set to false, removes integrity attribute on fallback so that different CSS can be loaded  -->
+    <link href="~/styles/site.min.css?a=b&c=d" rel="stylesheet" data-extra="test" title='"the" title'
+          integrity="XY7YsMemPf8AGU4SIX9ED9eOjK1LOQWu2dmCNmh+pQc="
+          crossorigin="anonymous"
+          asp-fallback-href="~/styles/siteIntegrity.css?a=b&c=d"
+          asp-fallback-test-class="hidden"
+          asp-fallback-test-property="visibility"
+          asp-fallback-test-value="hidden"
+          asp-fallback-href-integrity-check="false" />
+
     <!-- Fallback to static href with dynamic attributes -->
     <link href="~/styles/site.min.css?a=b&c=d" rel="@("stylesheet")" data-extra="@("test")" title='@(@"""the"" title")'
           asp-fallback-href="~/styles/site.css?a=b&c=d"

test/WebSites/HtmlGenerationWebSite/Views/HtmlGeneration_Home/Script.cshtml

@@ -1,4 +1,4 @@
-@*
+@*
     Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
     Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 *@
@@ -22,6 +22,33 @@
     <script src="~/blank.js" asp-fallback-src-include="**/site.js" asp-fallback-test="false" title='"the" title'>
         // Fallback to globbed src
     </script>
+    
+    <script src="~/styles/siteIntegrity.js?a=integrity"
+            asp-fallback-src="~/styles/sub/site2.js?a=integrity"
+            asp-fallback-test="true"
+            crossorigin="anonymous"
+            integrity="sha256-tMQLOHBNPE829MHQPO8metegsGobA/henDPOvtZOWhQ=">
+       // Script loading primary source, applied integrity hash to primary source.
+    </script>
+
+    <script src="~/styles/siteIntegrity.js?a=integrity"
+            asp-fallback-src="~/styles/sub/siteIntegrity2.js?a=integrity"
+            asp-fallback-test="false"
+            asp-fallback-integrity-check="true"
+            crossorigin="anonymous"
+            integrity="sha256-tMQLOHBNPE829MHQPO8metegsGobA/henDPOvtZOWhQ=">
+
+       // Script uses fallback source, applies integrity hash to fallback.
+    </script>
+
+    <script src="~/styles/siteIntegrity.js?a=integrity"
+            asp-fallback-src="~/styles/sub/siteIntegrity3.js?a=integrity"
+            asp-fallback-test="false"
+            asp-fallback-integrity-check="false"
+            crossorigin="anonymous"
+            integrity="sha256-tMQLOHBNPE829MHQPO8metegsGobA/henDPOvtZOWhQ=">
+       // Script uses fallback source, ignores integrity hash on fallback.
+    </script>
 
     <script src="~/blank.js"
             asp-fallback-src-include="**/*.js"

test/WebSites/HtmlGenerationWebSite/wwwroot/styles/siteIntegrity.css

@@ -0,0 +1,6 @@
+body::after {
+    display: block;
+    color: #0fa912;
+    margin-top: 2.4em;
+    content: "Stylesheet 'siteIntegrity.css' loaded successfully!";
+}

test/WebSites/HtmlGenerationWebSite/wwwroot/styles/siteIntegrity.js

@@ -0,0 +1,6 @@
+(function () {
+    var p = document.createElement("P");
+    p.appendChild(document.createTextNode("Integrity Script loaded successfully!"));
+    p.style.color = "#0fa912";
+    document.body.appendChild(p);
+})();

test/WebSites/HtmlGenerationWebSite/wwwroot/styles/sub/siteIntegrity2.js

@@ -0,0 +1,6 @@
+(function () {
+    var p = document.createElement("P");
+    p.appendChild(document.createTextNode("Integrity Script loaded successfully!"));
+    p.style.color = "#0fa912";
+    document.body.appendChild(p);
+})();

test/WebSites/HtmlGenerationWebSite/wwwroot/styles/sub/siteIntegrity3.js

@@ -0,0 +1,6 @@
+(function () {
+    var p = document.createElement("P");
+    p.appendChild(document.createTextNode("Integrity Script with different hash loaded successfully!"));
+    p.style.color = "#0fa912";
+    document.body.appendChild(p);
+})();