Cherry pick 3657 to 1.6

.github/actions/spelling/expect.txt

@@ -429,6 +429,7 @@ SMTO
 sortof
 sourceforge
 SOURCESDIRECTORY
+sourceversion
 spamming
 SPAPI
 Srinivasan

src/AppInstallerCommonCore/Downloader.cpp

@@ -1,6 +1,5 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
-
 #include "pch.h"
 #include "Public/AppInstallerErrors.h"
 #include "Public/AppInstallerRuntime.h"
@@ -17,6 +16,9 @@
 using namespace AppInstaller::Runtime;
 using namespace AppInstaller::Settings;
 using namespace AppInstaller::Filesystem;
+using namespace winrt::Windows::Web::Http;
+using namespace winrt::Windows::Web::Http::Headers;
+using namespace winrt::Windows::Web::Http::Filters;
 
 namespace AppInstaller::Utility
 {
@@ -141,6 +143,37 @@ namespace AppInstaller::Utility
         return result;
     }
 
+    std::map<std::string, std::string> GetHeaders(std::string_view url)
+    {
+        AICLI_LOG(Core, Verbose, << "Retrieving headers from url: " << url);
+
+        HttpBaseProtocolFilter filter;
+        filter.CacheControl().ReadBehavior(HttpCacheReadBehavior::MostRecent);
+
+        HttpClient client(filter);
+        client.DefaultRequestHeaders().Connection().Clear();
+        client.DefaultRequestHeaders().Append(L"Connection", L"close");
+        client.DefaultRequestHeaders().UserAgent().ParseAdd(Utility::ConvertToUTF16(Runtime::GetDefaultUserAgent().get()));
+
+        winrt::Windows::Foundation::Uri uri{ Utility::ConvertToUTF16(url) };
+        HttpRequestMessage request(HttpMethod::Head(), uri);
+
+        HttpResponseMessage response = client.SendRequestAsync(request, HttpCompletionOption::ResponseHeadersRead).get();
+
+        THROW_HR_IF(
+            MAKE_HRESULT(SEVERITY_ERROR, FACILITY_HTTP, response.StatusCode()),
+            response.StatusCode() != HttpStatusCode::Ok);
+
+        std::map<std::string, std::string> result;
+
+        for (const auto& header : response.Headers())
+        {
+            result.emplace(Utility::ConvertToUTF8(header.Key()), Utility::ConvertToUTF8(header.Value()));
+        }
+
+        return result;
+    }
+
     std::optional<std::vector<BYTE>> DownloadToStream(
         const std::string& url,
         std::ostream& dest,

src/AppInstallerCommonCore/Public/AppInstallerDownloader.h

@@ -7,6 +7,7 @@
 #include <wrl/client.h>
 
 #include <filesystem>
+#include <map>
 #include <optional>
 #include <ostream>
 #include <string>
@@ -59,6 +60,9 @@ namespace AppInstaller::Utility
         bool computeHash = false,
         std::optional<DownloadInfo> info = {});
 
+    // Gets the headers for the given URL.
+    std::map<std::string, std::string> GetHeaders(std::string_view url);
+
     // Determines if the given url is a remote location.
     bool IsUrlRemote(std::string_view url);