From e8d472b65bf25f831a1054a1bf8552725a22fff3 Mon Sep 17 00:00:00 2001
From: Ilya <darpa@yandex.ru>
Date: Wed, 8 Jan 2020 01:25:30 +0500
Subject: [PATCH] Ignore headers with null values in web cmdlets (#11424)

---
 .../WebCmdlet/Common/WebRequestPSCmdlet.Common.cs | 11 +++++++++--
 .../WebCmdlets.Tests.ps1                          | 15 +++++++++++++++
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/src/Microsoft.PowerShell.Commands.Utility/commands/utility/WebCmdlet/Common/WebRequestPSCmdlet.Common.cs b/src/Microsoft.PowerShell.Commands.Utility/commands/utility/WebCmdlet/Common/WebRequestPSCmdlet.Common.cs
index 4c5d3e8227..133ca142f4 100644
--- a/src/Microsoft.PowerShell.Commands.Utility/commands/utility/WebCmdlet/Common/WebRequestPSCmdlet.Common.cs
+++ b/src/Microsoft.PowerShell.Commands.Utility/commands/utility/WebCmdlet/Common/WebRequestPSCmdlet.Common.cs
@@ -663,8 +663,15 @@ namespace Microsoft.PowerShell.Commands
             {
                 foreach (string key in Headers.Keys)
                 {
-                    // add the header value (or overwrite it if already present)
-                    WebSession.Headers[key] = Headers[key].ToString();
+                    var value = Headers[key];
+
+                    // null is not valid value for header.
+                    // We silently ignore header if value is null.
+                    if (!(value is null))
+                    {
+                        // add the header value (or overwrite it if already present)
+                        WebSession.Headers[key] = value.ToString();
+                    }
                 }
             }
 
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Utility/WebCmdlets.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Utility/WebCmdlets.Tests.ps1
index 2e234ea594..8949d56db5 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Utility/WebCmdlets.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Utility/WebCmdlets.Tests.ps1
@@ -3496,4 +3496,19 @@ Describe "Web cmdlets tests using the cmdlet's aliases" -Tags "CI", "RequireAdmi
         $result = Invoke-RestMethod $uri
         $result.Hello | Should -Be "world"
     }
+
+    It "Web cmdlets ignore headers with null value" {
+        $query = @{
+            body        = "hello"
+            contenttype = 'text/plain'
+        }
+        $uri = Get-WebListenerUrl -Test 'Response' -Query $query
+
+        # Core throws if a header has null value.
+        # We ignore such headers so no exception is expected.
+        { Invoke-WebRequest -Uri $uri -Headers @{ "Location" = $null } } | Should -Not -Throw
+        { Invoke-WebRequest -Uri $uri -ContentType $null } | Should -Not -Throw
+        { Invoke-RestMethod -Uri $uri -Headers @{ "Location" = $null } } | Should -Not -Throw
+        { Invoke-RestMethod -Uri $uri -ContentType $null } | Should -Not -Throw
+    }
 }